Yet Another Cycling Forum
General Category => The Knowledge => Topic started by: quixoticgeek on 19 January, 2020, 08:21:52 pm
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I have been sceptical about hydraulic brakes for a while, primarily from the point of view of how they can be repaired at the side of the road, one pair on SRMR01 scratched due to hydraulic brake failure, which has put me off. But having recently used hydraulic brakes on the work bikes, I am finding the stopping power really rather appealing. Coupled with James commenting that he's had 80000km without any faults using hydraulic brakes, is making me wonder if I should reevaluate my prejudice.
How serviceable are hydraulic brakes? How much fluid do they need? Could I bodge a fix at the side of the road if I had a spare hose and enough oil? Are all shimano hydraulic brakes compatible? I.e. can I use a MTB brake with a road brake lever? Has anyone had their hydraulic disk brakes fail?
My use case is audaxing and ultraracing, if that has any impact on the answers.
Thanks
J
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In my experience they’re very reliable and close to maintenance free, but I’ve only had them a couple of years.
Shimano road and MTB callipers are interchangeable, but note there are two different fittings at the hose end (banjo and straight) and the newer road levers need a different nut at the lever end.
The amount of fluid in the system is tiny - single digits ml I’d guess.
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If I were you I’d look for some old stock RS785 Di2 levers, which I’ve seen ludicrously cheap and are often bundled with post mount callipers.
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I've found them pretty damn reliable (shimano). I'd favour Shimano over other brands purely to avoid using DOT fluid.
Whether they are mendable on the road depends on the issue, but personally I've had no problems with mine in 4 years. Personally, I'd prefer not to open the system in any way on the road just to avoid contamination....but I've never needed to.
In fact, I've bled them now and again and replaced the oil just because I can and not because they have felt like they needed it.
Like all components they have a lifespan and will eventually deteriorate, and it is worth getting very acquainted with them before embarking on a long trip.
Most likely issues? Stripping the pad retaining bolt if you have tightened it too much previously or not used anti-seizure on the threads. Misalignment of the caliper leading to weird pad wear. Sticky pistons if used in dusty conditions.
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What about the Hope RX4 calipers?
There is a version for post mount, and compatible with Shimano levers.
Maybe more reliable and serviceable? Hope can probably supply any spare parts if necessary.
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How serviceable are hydraulic brakes?
Very. Shimano make a DIY bleed kit that doesn't need a PhD.
How much fluid do they need?
I regularly bleed mineral oil systems in the workshop and rarely need more than 25ml to flush or refill
Could I bodge a fix at the side of the road if I had a spare hose and enough oil?
Yes. It's about as likely as you severing a cable in a crash. It's much more probable that your discs wll get contaminated with oil/diesel on a long wet ride and brake performance will suffer. You would be better off carrying alcohol wipes.
Are all shimano hydraulic brakes compatible? I.e. can I use a MTB brake with a road brake lever?
Up to a point. Yet again several 'standards' exist. Mainly 'post mount' and 'flat mount'. The best response to the question is 'Why bother?' IOW just buy the correct brake for your bike setup
Has anyone had their hydraulic disk brakes fail?
It's usually down to a lack of maintenance. Unless it's dickheadedness.
'Why don't they work?'
'There's oil all over the discs. How did that happen?'
'They were squealing...'
All that said if you are currently using cable discs with STi levers then consider buying a pair of TRP Hy-Rd calipers. Available in post or flat mount, they work best with compressionless outer and the best cables you can afford. Each caliper has a reservoir and master cylinder piggy-backed on to it, which doesn't affect your choice of lever.
They use the most common Shimano pattern pads (B-01S) and, if you have an off sufficient to render them U/S, you're going home in an ambulance.
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17 years of hydraulics on mtn bike. Never had them fail or ripped hoses out.
End of last year I built a new recumbent with Shimano XT hydraulics.
I cut the hoses and added the necessary fittings. A 7/8mm spanner for bleed screws and tightening the compression nut at the lever end, Allen key for banjo or other connector at calliper end. Two syringes (ones from a pharmacy will do) and short lengths of clear tubing for adding the mineral oil. I used about 25ml of oil when setting up each brake even on the longer rear hose. So 50mL of mineral oil would do the job for both.
You could pre cut spare hoses and add fittings if that’s your concern but I think it’s pretty unlikely unless someone sabotages your bike. It’s be like carrying a welding rig in case your frame breaks.
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Here’s a page with views of the hose and fittings. It’s pretty simple.
https://jagwire.com/products/hydraulic-hose/mountain-pro-quick-fit-adaptor-kits
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Hmmm, some fairly comprehensive answers.
Hydros are good, I've got a set of 785's going back to 2015 that have been on five different bikes and are still going strong.
When it comes to audaxing and ultra racing though? Dunno, still rather go with mechanical. As an unknown if a failure were to occur you are looking at a brake cable, pliers/cable cutters and a 5mm allen key (which you should already have on you) so the cable is only the extra bit of kit, and is fairly easy to do by the road side even when it is dark and pissing it down.
A hydro failure though, at it's worst to fit a new hose and bleed it is niche given the tools that you would need:-
On the assumption that the hose is pre cut and fitted with the connectors.
Two olives
The container which mounts to the bleed port.
Small bottle of mineral oil
bleed hose and sandwich bag or some syringes for the bleeding
bleed block that fits into the caliper
pliers/7mm spanner for the bleed nut
pliers/flat head to remove the split pin/screw to remove the pads
8mm spanner for the connector on a shimano system
And maybe some new pads given that if the hose were to fail and the oil go over the pads they would be useless.
Maybe some tissue to wipe down after you were finished as any sort of contamination as above would render the pads useless.
Too much agg imo.
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I have very recently converted my jolly green giant from using TRP spyres to Shimano 105 hydraulic (or more accurately my LBS did it while I was away off in Scotland). I used to have the same concerns as you concerning reliability. But I found that mechanical discs do have their own foibles, especially on long hilly and wet rides where pads can be worn and cables stretched to the point where braking is compromised. On rides like my attempt of the Mallorca Moonpig I had to adjust the calipers with an Allen key halfway through. With hydros the pistons self adjust so you have consistent braking throughout the ride. Further, spyres can have mechanical bits go breaking. The barrel adjuster on my front one unfortunately broke very fast.
I have since done about 1000 km with the new hydros which is about 5 * 125 km rides, 2 100 km rides and one 200 audax. I haven't yet done any fettling especially bleeds which I understand should be done approximately once yearly for road bikes.
I don't think I'd want them for a round the world tour - that's for a 26" set of v braked wheels - but for any kind of long distance race, first world tour or audax I think they're a safe bet so long as servicing is kept up to date.
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The best hydraulic brake set up I have is a pair of 12+ year old Hope Minis that came fitted to a recent secondhand hard tail purchase. The bike didn't show any signs that it had been particularly well maintained over the years, but bloody hell the brakes work brilliantly despite the lack of maintenance. Conversely the relatively new TPR spyres on my road bike are just okay in terms of performance but I can't see them lasting a decade or more and they certainly don't fill me with confidence on fast descents. Dare I suggest that road disc brakes are a bit like road tubeless tyres in that they can work, but they lose the significant advantages over the "use case" they were originally designed for. Personally, I'd favour full cable discs for a road bike, even if a bit of adjustment is needed on long rides.
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Just looking at my bike history:
Focus Ultegra Hydraulics 16,913.4km
Issues: I broke the pistons by being a dick (not cleaning them and then trying to force the pads apart, it was at this point i discovered that the ceramic pistons on Shimano road brakes are considerably more fragile than the ones on MTB units)
Genesis 105 Hydraulics 5,239.7 km
I learnt the lesson on the Focus
GT Zaskar 4,168.8 km including the Puffer, Relentless and various other modes of abuse in the Scottish wilderness
This has had 2 sets of brakes
The first was the good old BR-M535 levers and calipers, I once managed to run out of fluid in them, not sure how but I only discovered before heading out to do the classic Mount Keen and Fungle road loop, I dumped some 3 in one into them and they worked, flushed them out and replaced ASAP after that.
Replaced them with the new blingy servo wave XT levers and calipers because I wanted to, I did manage to over presurize the system when bleeding (i.e. being a dick again) the seals don't blow so I re-read the instructions and tried again.
Rocky 4,345.1 km
This has Avid Elixer 3s on it; other than using DOT fluid which is scary stuff I've had no real problems with them.
Common problems I've had over all of them...
The ones that use a bolt for pad retention, pretty much every single one I've ended up replacing with split pins due to cack handedness on attempting to remove (either by hex head or flat head)
You can probably see that in every single issue listed the common element of failure is me.
Particularly on the MTB despite various stacks including sliding down a mountain* side tangled in the bike after toppling off a staircase, and dragging them through trees and bushes either voluntarily or accidentally, I've not yet managed to haul the pipe out of the fixing on either lever or calliper.
I've also used BB7 Road cable brakes, they're tolerable.
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Avoid DOT 5.1 systems and anything without provision for fluid expansion.
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I have not yet had a problem stopping with BB7 roads on the recumbent, even on a loaded tour. I can't think where it would have been to my advantage to have been able to lock up more quickly.
The advantage of the Bb7s to me is road side fettlability, just a quick tweak on the adjusters at a control, spare cable and pads in rack pack.
In the case of hydraulics though, I'm not sure I'd bother with carrying repair kit, other than perhaps spare pads. I'd simply accept that I ride cautiously with one brake until I can deal with it properly.
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It's not just about power. There are a load of other advantages ....better modulation, no sticky cables/cable contamination, no degrading of function, no cables to replace (as well as the obvious disadvantage of more involved maintenance needing cleanliness and simple but specialist equipment).
Over 17 years I've had 3 sets of cable-disc brakes and the honest answer is none of them were even close to the functionality of the one set of Shimano hydros I've been using for 4 years, and all of them were more frustrating to keep working properly. (Avid/Sram BB, Juintech R1, Spyre)
I dont think I'd ever choose mechanical discs again. The disadvantages outweigh any advantage over rim brakes.
But, again, I dont think I'd want to have to attend to hydro issues at the roadside. It's a simple process but can involve fiddly bit and pieces.
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I'm going to be talking to Airnimal this week, and another thought comes to mind here, that of travelling with hydraulics. Does travelling by plane with the bike in the hold cause any issues?
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My mob did a trip to Mallorca and a few of us had hydros. No problems with the brakes though they did make sure to stuff some train tickets or brake blocks into the calipers to prevent them being squeezed shut. Hydro fluid is very robust it takes extreme temperatures for it to start doing anything odd.
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I was thinking more about the reduced cabin pressure,
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Could I bodge a fix at the side of the road if I had a spare hose and enough oil?
On the off-chance it's useful to someone at some point, it looks like baby oil might be a viable bodge if needed: https://www.youtube.com/watch?v=63VIuPiX3CA
The brake bleeds I've done have all benefited from a workstand to get either the rear hose line favourably angled up towards the lever, or the bars low enough that I could see into the plastic pot on the levers to watch for bubbles. Also copious amounts of isopropyl alcohol and blue roll. If it did become necessary to do a roadside fix, I'm curious to learn to what extent these are nice-to-haves or necessities.
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I’d consider replacing a hose or a knackered calliper a bike shop job. If you go with the RS785 levers they use standard MTB callipers and hose connectors, which I’m sure you can find in most places TCR goes.
On the other hand, I’d think the chances of that sort of catastrophic failure not likely enough to be worth worrying about.
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A fellow crashed during the last day of PBP Audax 2016, twisting a brake lever and pulling the hydraulic line out. A crash could fairly easily take out a road hydraulic brake when a cable lever could just be pushed back into place. You pays your money and...
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A fellow crashed during the last day of PBP Audax 2016, twisting a brake lever and pulling the hydraulic line out. A crash could fairly easily take out a road hydraulic brake when a cable lever could just be pushed back into place. You pays your money and...
I crashed on my touring bike, the full impact was taken by the sticky out cant brake arm and snapped the boss off. Yes, you pays your money...
Whats the chances of buggering up both brakes? In an emergency I'd rather continue with just a front only rather than a rear. I don't know if it's universal but on mine it'd be a simple roadside job to swap them round.
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I'm going to be talking to Airnimal this week, and another thought comes to mind here, that of travelling with hydraulics. Does travelling by plane with the bike in the hold cause any issues?
My Joey is staying mechanical, the folding does odd things to the cables, they're more likely to get tangled and strained than on a conventional bike. Depends how you plan on transporting it of course, mine gets bagged and handled by others. I did consider a hydraulic on the front and removing it to transport, but it's more hassle than I'm happy with.
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I have hydraulics on my commuting bike and they've been bullet proof.
I'm about to replace on of the hoses as I can see that the out casing is worn from rubbing against another cable - this has probably taken about 5 years to wear to that point.
I'm on my second set of discs, the old ones eventually wore to the point that they were too thin for the pads to effectively self-adjust at the end of their travel.
I'd say at the most cautious, the hybrid cable-activated hydraulics might be worth trying.
These have been getting really good reviews and are much more compact than the TRP Hy-Roads: https://cyclingtips.com/2017/03/yokozuna-motoko-disc-brake-review-no-new-levers-required/
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I have ridden with people using cable-hydros. The main point of them as far as I can tell is that it makes it possible to convert without an inordinately expensive purchase of new shifters etc, especially with something like Giant's proprietary unit https://www.giant-bicycles.com/global/showcase/conduct
They don't half make an odd noise on the rotors when it's been wet. If I'm honest I just presume they need a bit more looking after than straight hydraulics as there are more 'junctions' in the system. They seem to work OK though.
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Avoid DOT 5.1 systems and anything without provision for fluid expansion.
Interestingly, the only hydro brakes I has problems with were some Giant (IIRC) proprietary ones, with a large (relatively) reservoir at the lever. In hot weather that heated up and caused fluid expansion that locked the brakes on.
Shimano have a tiny sealed reservoir in the lever, and work well.
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I was thinking more about the reduced cabin pressure,
Passenger aircraft holds are normally pressurised. There's really no reason these days to deflate tyres...
I'll throw a curve ball in... hydraulic rim brakes. I have Magura's (https://www.magura.com/en/components/bike/rim-brakes/productdetailpage/?p=2597) on my vsf Farrhadmanufaktur touring bike and my Kalkhoff electric bike. Great stopping power - even with a lard arse like me on board.
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Big fan of HDB. So nice to use on the sort of races we do.
35,000 km on my endurance bike and no problems.
Ive had the brakes serviced once by a mate. (Im not capable and would be in trouble if a drama happened mid ride)
The one thing that concerns me is when travelling with a fairly small soft bike bag. I have to twist the fires which does put strain on and pinch the brake line.
Other than that they have been bomb proof.
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I have not yet had a problem stopping with BB7 roads on the recumbent, even on a loaded tour. I can't think where it would have been to my advantage to have been able to lock up more quickly.
The advantage of the Bb7s to me is road side fettlability, just a quick tweak on the adjusters at a control, spare cable and pads in rack pack.
In the case of hydraulics though, I'm not sure I'd bother with carrying repair kit, other than perhaps spare pads. I'd simply accept that I ride cautiously with one brake until I can deal with it properly.
The one major downside of BB7s that I will claim is their use of the Avid Juicy pads and retention spring.
That and being tricky to set up just right are about all I can fault them on in terms of being decent brakes.
Hot Flautus' list however does give a good idea of where Hydraulics really are better.
The M535s needed bled regularly,
I've only bled the newer shimano ones when building or replacing the calipers I broke the pistons on.
They're probably due a full oil change now I think of it.
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I was thinking more about the reduced cabin pressure,
Passenger aircraft holds are normally pressurised. There's really no reason these days to deflate tyres...
There never was a reason to deflate tyres, they'd be fine in hard vacuum (it's only another 14.5PSI). Hydraulics might be more fussy...
I'll throw a curve ball in... hydraulic rim brakes. I have Magura's (https://www.magura.com/en/components/bike/rim-brakes/productdetailpage/?p=2597) on my vsf Farrhadmanufaktur touring bike and my Kalkhoff electric bike. Great stopping power - even with a lard arse like me on board.
For something that combines the disadvantages of both, these are unexpectedly lovely. You get the power and modulation (and sometimes self-adjustment, depends on the model) of hydraulic discs, low maintenance and much simpler pad adjustment than V-brakes (more like a disc brake). But you also get the water-clearance lag and rim wear you expect from rim brakes. I don't think you can get road levers for them, though.
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Not so common any more but Magura HS 66 are nice levers.
https://www.cxmagazine.com/tbt-magura-hydraulic-cantilever-brake-drop-bar-lever-hs66-hs77-rim
SRAM did a rim brake option.
https://www.velonews.com/2013/06/news/tour-tech-mark-cavendishs-sram-hydror-hydraulic-rim-brakes_292513
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I was thinking more about the reduced cabin pressure,
Passenger aircraft holds are normally pressurised. There's really no reason these days to deflate tyres...
There never was a reason to deflate tyres, they'd be fine in hard vacuum (it's only another 14.5PSI). Hydraulics might be more fussy...
I'll throw a curve ball in... hydraulic rim brakes. I have Magura's (https://www.magura.com/en/components/bike/rim-brakes/productdetailpage/?p=2597) on my vsf Farrhadmanufaktur touring bike and my Kalkhoff electric bike. Great stopping power - even with a lard arse like me on board.
For something that combines the disadvantages of both, these are unexpectedly lovely. You get the power and modulation (and sometimes self-adjustment, depends on the model) of hydraulic discs, low maintenance and much simpler pad adjustment than V-brakes (more like a disc brake). But you also get the water-clearance lag and rim wear you expect from rim brakes. I don't think you can get road levers for them, though.
Yes aircraft holds are pressurised, but only to about 8-10000ft. There is a manufacturers warning on my insulin pump that it might behave oddly at those pressures, so monitor blodd glucose more regularly. I'm joining ...
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A fellow crashed during the last day of PBP Audax 2016, twisting a brake lever and pulling the hydraulic line out. A crash could fairly easily take out a road hydraulic brake when a cable lever could just be pushed back into place. You pays your money and...
I heard of a similar incident on one of the TINATs. In that case, the rider was able to carry on, though injured, riding carefully with only a rear brake.
But it's just something I was told about, albeit by someone who was riding with the person, I didn't see it myself. And we probably don't hear if crashing happens with cables leads to a smashed lever, for instance, unless we know the rider. And all of these are going to be rare cases.
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I've crashed during races and general rides, pushed the brake lever back straight and continued riding more than once.
I see hydraulic brakes as akin to electronic shifting - great if it works and it probably will continue to work but if it stops working, it is probably a pain in the arse/ expensive to fix.
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I had a hydraulic brake failure, rear Shimano caliper had a leak, most likely from the transfer port seal (the caliper is made in two halves and there is a port between them with a small rubber seal). This was a warranty replacement, it was likely something like the seal having been pinched during assembly in the factory, or perhaps a casting issue. It was slowly losing fluid and replacing it with air, and this showed up when I inverted the bike to work on something, and the air got into the hose, and suddenly no rear brake.
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We've got the on the Circe tandem. I have had to bleed the rear brake a few times. It's a bit annoying.
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What I do find is that I have to drop the wheel out and pump the pistons out to lessen the travel every few weeks.
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Avoid DOT 5.1 systems and anything without provision for fluid expansion.
Most Hope brakes use DOT 5.1, they work great. Its not really a problem.
Just don't leave the bottle with the lid open, or spill it over your bike, or drink it... 🤢
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Whereas Shimano hydraulic fluid makes an interesting martini?
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Well, it's not hygroscopic and isnt a paint stripper. It also doubles as a lube for mavic hubs.
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I've got some Juin Tech F1s waiting to go on my new bike. I don't know if i like them yet, but they seemed like a reasonable compromise on features.
Why not hydraulics? (I think I've said it before, but) partly the roadside fixability. Mostly that i haven't found integrated shifters that i like. When I've felt lack of stopping on a road bike it was mostly at the tyre / road interface rather than the brakes.
Sent from my SM-G930F using Tapatalk
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It's not really about stopping power.
I had some Juins. I no longer have Juins.
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The useful travel on drop bar levers is so short that self-adjustment is essential* with disc brakes to avoid them bottoming out on the bar, unless you plan to fettle them every 12 minutes. I don’t think the hybrid brakes come close to the feel of proper hydraulics though, if that’s the goal.
(* in my personal experience. I’m sure I’m an idiot who Isn’t Doing It Right)
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When I first got hydros the travel really bugged me. I bked and bled thinking that was the issue. Then I realised I just needed to periodically pump out the pistons by operating the brakes with no wheel every few hundred miles.
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there are pros and cons with every system, for me there is no clear winning technology. failures are very rare, it's pure chance whether something happens to you or it may never happen.
let's take my example on tinat 600. i crashed at around 160k, nothing major, only handlebars twisted to the side, right shifter/lever turned inwards 45 degrees and bent derailleur hanger. it took me a few minutes to sort it out and carry on. back then i was wondering if i'd been able to carry on had my bike had hydraulic brakes and electronic gears. maybe, maybe not.
another example. on hydraepic challenge my bike fell into muddy water and the left shifter filled up with mud. shifting became stiff and jammy. in this case electronic shifting would not have been affected at all (imo), so swings and roundabouts. touch wood i haven't had a ride ending mechanical on any of my long rides so far.
i like and use hydraulic brakes on one of the bikes, they work fine and don't require attention. as for "adventure" cycling, i'm not yet convinced they are the most suitable option (for me).
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Avoid DOT 5.1 systems and anything without provision for fluid expansion.
Interestingly, the only hydro brakes I has problems with were some Giant (IIRC) proprietary ones, with a large (relatively) reservoir at the lever. In hot weather that heated up and caused fluid expansion that locked the brakes on.
Shimano have a tiny sealed reservoir in the lever, and work well.
Giant MPH brakes (and some other models) were 'closed system'. If they are not bled properly they behave exactly as you describe. If they are 100% gas free and full of clean fluid, they rarely give the kind of trouble you describe.
Any hydro brake can of course misbehave if it is not bled or has the wrong amount of fluid in it (surprisingly common).
Shimano calipers fail to leaks either at the caliper half seal or in the piston seals. The cause is usually corrosion. I have a box full of failed calipers.
cheers
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Just back from a ride this morning. Sheeting rain, slick oily roads. Sand and grit.
I was on the endurance bike that has hydro brakes and wide tires so continued on.
On the regular road bike I would have gingerly headed straight home.
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Shimano calipers fail to leaks either at the caliper half seal or in the piston seals. The cause is usually corrosion. I have a box full of failed calipers.
cheers
Given you are not a mechanic and don’t work in a bike shop. How did you acquire a box full of failed calipers?
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Just back from a ride this morning. Sheeting rain, slick oily roads. Sand and grit.
I was on the endurance bike that has hydro brakes and wide tires so continued on.
On the regular road bike I would have gingerly headed straight home.
I test rode a bike with 28mm road tyres and BB7s today, not raining heavily, light drizzle and shitty cambridge roads with construction and farming mud all over. I carried on.
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Shimano calipers fail to leaks either at the caliper half seal or in the piston seals. The cause is usually corrosion. I have a box full of failed calipers.
cheers
Given you are not a mechanic and don’t work in a bike shop. How did you acquire a box full of failed calipers?
I offered an LBS to see why these brakes were failing so often. With my own brakes I would probably take the trouble to maintain them better and to perhaps repair them. However at shop labour rates it just isn't worth it, and even a tiny chance of a repair not being successful is enough to kybosh it entirely; a new caliper is a pretty reliable solution, for a year or so at least. After that if the caliper hasn't been treated with silicone grease and has been used on our lovely salt encrusted roads, chance of failure seem pretty high.
cheers
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i like and use hydraulic brakes on one of the bikes, they work fine and don't require attention. as for "adventure" cycling, i'm not yet convinced they are the most suitable option (for me).
Coincidentally, I am the opposite. I have one bike with hydraulic brakes, and that is my adventure bike. My experience with cable discs on hilly off-road rides was that it would become very tiring on the hands towards the end of a day, and the prospect of multi-day races was not one that I wanted to contemplate with the Spyres. I have found the hydraulic brakes work much better for such terrain, and aren't tiring.
On the road, the Spyres have been fine. Stopping power is more than sufficient for even the most hilly or rides, and I have not suffered the same fatigue as I would get off-road. If I were to choose a new setup for a road-oriented bike, it would be a close call. I would just be careful to service the hydraulic brakes before any particularly big event, or series of events.
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Yep hydraulics are pretty reliable and I've yet to have any fail in 17 years of use. Sure there's edge cases out there but there's edge cases like your frame failing. Some on here seem to have a magnified sense of the likelyhood of them failing.
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Things I've learnt from three years of using shimano hydraulic brakes (RS505 levers, BR-RS785 brake calipers)
The hydraulic fluid port screw is really easy to lose, I have bought spares as there's never a good time to lose one of those screws.
It pays to remove the brake calipers and give them a clean from time to time, dust and grit can sit around the pistons, cleaning these will help ensure they perform better when in service.
The first time I bled the brakes I managed to leak fluid everywhere, I now keep paper towels handy in case.
I wipe the discs with a dry paper towel to remove contamination from time to time, this improves braking and reduces noise and also it's a good opportunity to check the disc for wear and damage.
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Just had a very disappointing day. I hadn't used the posh bike with the discs on it for a few weeks and wheeled it out for an audax this morning. Headed off down the road and was very alarmed that the levers were barely operating the brakes. I was pulling them right to the bar and they would barely function.
Shimano 105 hydros put on in late November.
Immediately emailed the organiser to say I was dnsing. I was sure that they could be relied on but this has really fucked me off. I hope the lbs would sort me out but this has left me pretty fed up. Never had this happen with my trp spyres obviously.
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Immediately emailed the organiser to say I was dnsing. I was sure that they could be relied on but this has really fucked me off. I hope the lbs would sort me out but this has left me pretty fed up. Never had this happen with my trp spyres obviously.
Do you have the ability to bleed them yourself?
When did you last ride the bike?
J
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Was the bike stored horizontally?
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No I don't have bleed stuff. My understanding was that a bleed was normally done once or twice yearly not after 3 months!
Last ride on the green bike was 1/2/20. I did pump the brakes for a while hoping they might suss themselves out, including about 2 minutes of riding up and down and slowing, but no changes.
Bike was stored vertically, front wheel up. It's how I prefer to store a steel frame so that it drip-dries.
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No I don't have bleed stuff. My understanding was that a bleed was normally done once or twice yearly not after 3 months!
Given the cost of the bleed kit is only about €20, wouldn't it be a useful thing to have in the tool box.
Last ride on the green bike was 1/2/20. I did pump the brakes for a while hoping they might suss themselves out, including about 2 minutes of riding up and down and slowing, but no changes.
Bike was stored vertically, front wheel up. It's how I prefer to store a steel frame so that it drip-dries.
What servicing has the bike had since you got it?
J
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What servicing has the bike had since you got it?
Got the bike in November 2018 https://yacf.co.uk/forum/index.php?topic=111306.0
In late November 2019 I had worn out a lot of the components on it to a horrible degree and so decided to just pay the LBS to upgrade to 105 since I like the frame a lot. In so doing they fitted:
New BB
100% Shimano 105 hydraulic groupset
New Hope Pick'N Mix headset
I picked this up from them in the 3rd week of December and did the festive 500 on it. According to Strava (I track the components as I swap them on and off) I have done less than 1500 km on it since the rejig.
I did mean to get round to getting a bleed kit at some point and learning to use it but ffs surely 3 months is a bit soon!
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What servicing has the bike had since you got it?
Got the bike in November 2018 https://yacf.co.uk/forum/index.php?topic=111306.0
In late November 2019 I had worn out a lot of the components on it to a horrible degree and so decided to just pay the LBS to upgrade to 105 since I like the frame a lot. In so doing they fitted:
New BB
100% Shimano 105 hydraulic groupset
New Hope Pick'N Mix headset
I picked this up from them in the 3rd week of December and did the festive 500 on it. According to Strava (I track the components as I swap them on and off) I have done less than 1500 km on it since the rejig.
I did mean to get round to getting a bleed kit at some point and learning to use it but ffs surely 3 months is a bit soon!
If you had put brand new cable operated brakes on, a few weeks or a few hundred km later you would be wanting to check they have bedded in correctly and adjust them. Same as you do when buying a new bike. Not unreasonable to expect something similar needing to be done to hydraulic brakes.
J
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if the brakes had been bled properly, correct fluid used, no road salt lurking in the piston bores and no contamination with the wrong oils etc that might have got onto the seals, the brakes shouldn't need anything doing to them yet. So I'd suspect that your brakes were/are deficient in one or more of the above respects.
Of course there's no way to be sure what happened, not without more diagnostic work. However I'd be suspicious that as the bike was last used in December, there might be contamination in the caliper bores, and that this might have caused corrosion and therefore leakage of hydraulic fluid and/or air. It happens often.
cheers
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Mine needed bleeding after about a week. The shimano ones come in a handy prefilled set up with a one time seal so they can be assembled at a bike shop without messy liquids and bleeding. It does not appear to always work perfectly.
I had a bit of a catastrophic failure last week - one in a million, picked up some debris off the road - (ironically some wire that looks like it might be a brake cable) and need a new calliper. I rode (gingerly) the last 40km on just the rear brake and it was fine. I am therefore now on my old bike whilst waiting for parts. The first trip out I thought the brakes weren’t working but now I have mentally adjusted and rim brakes seem just fine.
Sent from my iPad using Tapatalk
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If you had put brand new cable operated brakes on, a few weeks or a few hundred km later you would be wanting to check they have bedded in correctly and adjust them. Same as you do when buying a new bike. Not unreasonable to expect something similar needing to be done to hydraulic brakes.
J
pads were bedded in fine. Made sure to do that as soon I picked it up and they performed fine for the rides I did until march.
I had used the bike since December - last did a recorded ride on Strava with is 1 February.
Will keep yacf abreast of what's gone on after I hand it in tomorrow...
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Bleeding brakes feels a bit daunting, I'm a newcomer to it, bought the Epic kit and followed their instructions, brakes now working better than when the LBS fitted them, plus it feels a lot less daunting, and of course I have the kit.
https://epicbleedsolutions.com/
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The shimano ones come in a handy prefilled set up with a one time seal so they can be assembled at a bike shop without messy liquids and bleeding.
I've just checked and the instructions for the easy hose system (https://si.shimano.com/pdfs/dm/DM-RADBR01-02-ENG.pdf) includes topping up the fluid via the funnel and burping out any bubbles.
If you skip this step the system will still work initially but won't have enough fluid in it to allow for brake pad wear, and might have a load of air in the reservoir. Which would cause a complete failure if it migrated into the hoses.
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Just had a very disappointing day. I hadn't used the posh bike with the discs on it for a few weeks and wheeled it out for an audax this morning. Headed off down the road and was very alarmed that the levers were barely operating the brakes. I was pulling them right to the bar and they would barely function.
Karma, isn't it?
Setting off to do a ride on a bike that hasn't been touched for ages is second only to using one where you've fettled something important the night before and not had an opportunity to test it.
(Yes, that was me at the 20km point yesterday slowly joining the dots between the loose front mech pivot bolt that I'd tightened and the inability to shift into either the big or - as it thankfully transpired before the grind up the Malverns - little ring...)
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^^^^^ agree with this
To be clear both front and rear brakes not working?
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Karma, isn't it?
Setting off to do a ride on a bike that hasn't been touched for ages
I mean by my standards it isn't unreasonable to think that a bike's braking system should be unaffected by it being left alone for a few weeks. I cleaned and lubed the chain the day before, gave the tyres a look at and checked the gears were functioning.... ::-)
Rear one seems to have a fair bit of play in it but it's definitely not nearly so ineffective.
A cautious ride to the shop is on the cards tomorrow...
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The shimano ones come in a handy prefilled set up with a one time seal so they can be assembled at a bike shop without messy liquids and bleeding.
I've just checked and the instructions for the easy hose system (https://si.shimano.com/pdfs/dm/DM-RADBR01-02-ENG.pdf) includes topping up the fluid via the funnel and burping out any bubbles.
If you skip this step the system will still work initially but won't have enough fluid in it to allow for brake pad wear, and might have a load of air in the reservoir. Which would cause a complete failure if it migrated into the hoses.
This is a shop with just two mechanics that has been setting up hydraulic braked bikes for years, I'd really hope they wouldn't miss something like that.... Here's hoping...
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Try tieing the levers back to the bars, leave it for a couple of hours, tapping the hoses from time to time. Do this with the bike the right way up.
If there's some air in the system and you're storing your bike without the reservoirs being the highest point, that air is going to end up in the hose or caliper.
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Try tieing the levers back to the bars, leave it for a couple of hours, tapping the hoses from time to time. Do this with the bike the right way up.
If there's some air in the system and you're storing your bike without the reservoirs being the highest point, that air is going to end up in the hose or caliper.
if you tie the levers back to the bars the compensation port will be closed and any air in the pressure circuit will remain in that circuit. Bubbles may rise to the top of the circuit but they won't do so any faster than normal and they won't be able to escape into the reservoir. NB transporting a bike with badly bled brakes is likely to go better if the levers are tied back, but there you are closing the compensation port to stop air in the reservoir (which shouldn't be there in the first place) from migrating into the pressure circuit.
IME it is much more effective to remove the disc (and/or pads) from the caliper, use the brake lever pump the pistons out (carefully, not too far) , and then (with the bike tilted if necessary eg in a workstand so the hose run (including the transfer ports in the caliper) is upwards all the way and the reservoir is uppermost) push the pistons back. Repeat if necessary.
The above will temporarily restore function to a brake that had air in the reservoir (i.e. it was never bled properly in the first place) and where that air migrated into the main part of the circuit , but still has intact seals and sufficient fluid (for the current state of pad wear) to at least fill the pressure circuit. Because you need no tools you can do this by the roadside if necessary, eg if the bike has been in a car or laid on its side and the brakes have gone bad.
If you use the same procedure but with a funnel attached to MC reservoir, and top it up with fluid as you go, you can add more fluid/remove air from the system. No need to break open the hydraulic circuit lower down, and/or use syringes etc, which can work fine, but also gives more opportunities to add air as well as remove it.....
If your brakes 'need bleeding after a week' , go bad after the bike has been hung up or turned upside down, or whatever, unless the fluid has escaped somehow (leaked out) it only ever means one thing; they were never bled properly in the first place.
cheers
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Well I've survived my trip to work - will carefully get it to the shop at lunch time... No magic improvement in braking overnight.
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As phil w said. Have had hydraulic brakes for ages probably 20years. Started with magura's now deore/xt, went down the Great Divide in 2001 so new touring bikes, went continental style touring. Mtb with front and rear racks no problems with the hydraulic brakes Everything improved when the metal pots changed to composite, no heat transfer to the seals or plastic tube. Early Hope disk brakes were a nightmare, but every part was available as a spare. 😀 If you are worried about things going wrong, make up a rear hose weights nothing a small syringe and a little mineral oil. That's all we take on tour. Most problems are air in the system, even flying never had to bleed the brakes.
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Well I've survived my trip to work - will carefully get it to the shop at lunch time... No magic improvement in braking overnight.
Verdict from the shop that fitted them?
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I wasn't able to pick the bike up this morning as I rode in to London on the other one for morning laps but popped in for a brief chat.
They've done a bleed and flushed the air out. But couldn't tell me how it had happened. I will go back tomorrow morning to pick it up try to get more detail. That will also give another 24 hours of it sitting there 'fixed' so I can be more sure that the problem is resolved.
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Rather than start another thread.
Last week, after 14 months and 16,000km I needed to bleed the front brake on my recumbent. I bled it and normal function resumed, all good. The rear brake didn’t need bleeding.
The front is a 406 wheel (rear 622) and I’ve ridden through some deepish floods of late. So front caliper may have gone underwater but not the rear. Is this coincidental or might riding through floods have anything to do with the front needing a bleed?
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Wouldn't have thought so Phil - Perhaps not right from the start off?
I've only bleeded (sp?) mine when something has changed like the hose being shortened or replacing the brake caliper (25,000km ago)
As long as the pistons are moving correctly and the system is air-free with new pads it should have enough fluid to cover the wear unless it leaks somewhere ?
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Yeah maybe I didn’t put in quite enough fluid to start. Which was fine with new pads but not once worn past a certain point.
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Did the first test ride with the new brakes today.
WHY OH WHY OH WHY, did I not do this upgrade sooner?
Gonna take me a few rides to get used to the increased stopping power. Grab a full handful of brake lever at a traffic light and I'm going to end up going straight over the bars.
The second brake was so much easier than the first.
J
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Great, aren't they :thumbsup:
It's not so much the power that I like but the control and modulation that you never get with cable discs.
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Wait till you use them on steep hills in the rain. Looveeeeerly
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Great, aren't they :thumbsup:
It's not so much the power that I like but the control and modulation that you never get with cable discs.
This.
Well, and you can take them to Wales for the weekend and still have stopping power at the end of it[1].
[1] To be fair this only happen to me once, due to not reading the small print on Wilko brake cable inners.
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Also you don't get the degradation you get with cables that get clogged with shite, or the need to constantly wind the pads out as they wear.
The only thing I don't like about the hydros is the length of lever travel. I can alter it on the DA lever set up on my summer bike, but it's still more than I prefer. On the older set up (1st gen Di2 hydro Ultegra) that came with mtb style calpers on a flat mount frame (because flat mount Road calipers hadn't been made available yet) there is no adjustment on the levers. So, when I have the bike in the stand I just drop the wheels and pump the pistons out a little. Minor hassle but I prefer a super short travel that replicates my road cable set up. Bit more travel on the rear to avoid locking the wheel.
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Great, aren't they :thumbsup:
It's not so much the power that I like but the control and modulation that you never get with cable discs.
This.
Well, and you can take them to Wales for the weekend and still have stopping power at the end of it[1].
[1] To be fair this only happen to me once, due to not reading the small print on Wilko brake cable inners.
I had a total loss of braking mid way through a January 200 using Juin-Tech cable/hydro hybrids (a bit like a cheap rip off of the TRP hybrid ones). Both brakes. They had been an absolute bugger to set up, and I had been having to adjust them mid ride, every ride. As the 200 was going to go through the Forest of Dean I knew I had to abandon. Fortunately I was in Gloucester, 10 miles from home, so I rode about 5 miles brakeless, but using feet as brakes, to a pub where I phoned my beloved who always likes a car rescue. Then train back to the start at Cardiff, where the lovely Ian L (otp) picked me up to recover my car just off the M4. Brakes went in the bin. Never really got to the bottom of the issue, but lost faith in them.
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I know someone who had the "expensive original" TRP HyRd and had continuous trouble with them. He eventually solved the problems by going to another system, but I can't remember now if it was fully cable or fully hydro. Either way, there seems to be some evidence (not just the two of you) that cable-hydraulic hybrid systems, theoretically best of both worlds, tend not to work well in practice.
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The thing I noticed during my brief dalliance with HY RDs is that they’re designed for far too much lever travel. It’s very easy to try to dial it out by shortening the cable, but then the piston never returns to its free position where the valve to the reservoir opens and self-adjustment can happen.
When you do have it set up “right” the levers pretty much touch the bar tape.
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I noticed that with my Juins, which, I believe are a rip off of the TrP HyRDs. Bloody awful things.
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Yes, my HY/RDs had more lever trace than I liked, although they were both reliable and effective. Better than any pure cable discs I’ve tried. The Shimano hydros are much better though and mine all allow lever trace adjustment, which as HF points out matters.
That said, I still don’t mind rim brakes...
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Leave it. It's not worth it. You and your little inviting '...' ;D ;D ;D
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Either way, there seems to be some evidence (not just the two of you) that cable-hydraulic hybrid systems, theoretically best of both worlds, tend not to work well in practice.
Worst of both worlds in reality. All the the issues with cables faff and not getting the benefit of hydraulic. Pointless in my view.
The main issue I gather is that a bit of cable stretch has a much bigger effect on the hydraulic piston travel than with cable brakes.
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Either way, there seems to be some evidence (not just the two of you) that cable-hydraulic hybrid systems, theoretically best of both worlds, tend not to work well in practice.
Worst of both worlds in reality. All the the issues with cables faff and not getting the benefit of hydraulic. Pointless in my view
My own experience is quite different. I replaced TRP Spyres with HyRd’s on my Croix de Fer and find them easy to to set up (YouTube is a friend) and easy to use, far more power and modulation than before and above all else confidence I’m actually going to stop when I need to. And at 18 Stone I take some stopping these days 😀
Each to their own, of course and I don’t dispute that a full hydraulic system would be stronger still
A
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I have the hydraulic discs on my new lightweight bike. They are a complete disaster and cause no end of trouble!
Almost every time I come to a stop my Garmin incident detection goes off!!
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I have the hydraulic discs on my new lightweight bike. They are a complete disaster and cause no end of trouble!
Almost every time I come to a stop my Garmin incident detection goes off!!
You might want to try modulating your braking a bit, Chris!
I've triggered the incident detection thingy a couple of times by braking hard - and not just on discs. My family took over 24 hours to respond by asking 'was that real?', so I disabled the alert...
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Tim, I was being slightly tongue in cheek as it is a boring morning. I am learning
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I have the hydraulic discs on my new lightweight bike. They are a complete disaster and cause no end of trouble!
Almost every time I come to a stop my Garmin incident detection goes off!!
You might want to try modulating your braking a bit, Chris!
I've triggered the incident detection thingy a couple of times by braking hard - and not just on discs. My family took over 24 hours to respond by asking 'was that real?', so I disabled the alert...
I stopped to mend somebody's puncture once and my watch started buzzing at me. As usual with Garmin watches, the ensuing instructions confused me slightly and the button I thought cancelled the alert actually confirmed it. I then worried that my very loving wife(who would receive the alert on her mobile) would panic and try and phone me...but my mobile had a flat battery so nobody would answer anyway, and this would create further panic.
I got home as quickly as I could. Turned out that my daughter had my wife's mobile phone, had seen the alert and ignored it ;D
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Both my bikes have hydraulic brakes, kind of. The fancy road bike has a factory SRAM set.
My commuting bike has a front hydraulic disc brake, and a rear cantilever brake. It's an old 1990 Ridgeback hybrid, so came with Cantilever brakes as stock. It also has a threaded headset...
Nethertheless, I had some cable disc brakes lying around from upgrading a previous bike to hydros, and the wheel needed replacing anyway, so I got a disc brake wheel and a new fork, some unbranded steel one off ebay, but it had disc mounts and a threaded steerer. So I plopped on the cable brakes.
A bit later, I upgraded that brake to a hydro. It's only the front brake that really benefits anyway!
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I'm wondering how long it's going to take for me to adjust to how good these brakes are the amount of movement needed to almost stop the bike vs the amount I needed to have any effect with my old brakes is just a world apart.
Did another ride this evening, only scared myself a couple of times...
J
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I'm wondering how long it's going to take for me to adjust to how good these brakes are the amount of movement needed to almost stop the bike vs the amount I needed to have any effect with my old brakes is just a world apart.
Did another ride this evening, only scared myself a couple of times...
J
Not as scary as the first time you go back to a bike with rim brakes.
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...in the wet
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...in the wet
This is where I find the difference. The difference in the dry between my disc equipped Equilibrium or Domane and my rim braked Argon 18 isn't something I've ever noticed, but in the wet, ah, yes.
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My other bike is a Brompton... The brakes are... more of an idea, than a useful part of the bike...
J
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Bah. You should try going back to a rod braked bike in the wet! :o
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I'm on the point of needing a new rotor for one of my bikes. It is a bike that has always had 140mm Shimano freeza rotors, apart from nov-april this last year when I used a dynohub wheel which had a steel 160mm rotor on it.
...and I've come to a few conclusions about this. I noticed that the Freeza rotors don't last that long, certainly in comparison to solid steel rotors. I also noticed that when I let a Freeza rotor wear to the limit I saw a crack appear. Turns out they have a relatively thin steel coating on an aluminium core...hence the freeza bit I suppose, because it must be about heat dissipation. I don't really like the thought of that crack in the steel coating. I also noticed that the solid steel rotor doesn't ping after heavy braking. In fact, I'd forgotten about the pinging until I removed the steel rotor and put the freeza rotor back on. But most of all I haven't noticed any improvement in braking since I put the Freeza back on. Plus the Freeza rotors are almost double the cost of steel ones.
So, I'm going to go on the hunt for a sold steel rotor and ditch the Shimano ones.
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Very much the experience of this fella:
https://youtu.be/utMchnpW1vo (https://youtu.be/utMchnpW1vo)
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Interesting, thanks! :thumbsup:
Now I know which rotor brand to go for. Hadn't occured to me to look at Campagnolo. Just got to check that there aren't compatibility issues, but he seems confident using them with Shimano calipers. Got a bit scared when he started talking about heat transferring into the hubs, boiling your bearing grease, and expanding the hub shell but I suppose that is more likely on mountainous terrain rather than the short descents we have here. I've never knocked mine out of true either, despite many trips in the car, just that annoying scraping or pinging sound after prolonged braking.
How many discs did he say he gets through in a year? :o
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For my main bike (Kinesis GFTi), I have a few sets of wheels depending on the time of year and what I'm using it for. Right now, it has a pair of Mavic Crosslights on with cheapish 6-bolt 160mm discs. For my use, they work just as well as the Shimano Freezas I have on the summer Hunt wheels. Incidentally (having just checked), the 'floating' feature of the Freeza/Hunt combo doesn't. Float, that is. They're as solid as the 6-bolt discs. Probably need to look into that before those wheels go back on...
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Yes, it was swapping back from steel rotors to freezas a week ago that got me thinking, and then a conversation with my riding partner, Steve, who was also getting pissed off with his discs. I'll give the Campag rotors ago and report back in a few weeks.
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It's news to me that they're meant to float. But before worrying about that or about heat dissipation and so on, I'd probably do better to give mine a clean.
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I’ve been happy with Hope floating rotors.
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My other bike is a Brompton... The brakes are... more of an idea, than a useful part of the bike...
J
I’ve never got this complaint. I’ve always found them super effective (2013 spec with Shimano pads).
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It's news to me that they're meant to float. But before worrying about that or about heat dissipation and so on, I'd probably do better to give mine a clean.
The "floating rotor" thing is just that the mounting spider and brake surface are different bits of metal, they don't really float but expand at different rates, which apparently helps with cooling and performance or something that probably only matters in Downhill MTB.
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It's news to me that they're meant to float. But before worrying about that or about heat dissipation and so on, I'd probably do better to give mine a clean.
The "floating rotor" thing is just that the mounting spider and brake surface are different bits of metal, they don't really float but expand at different rates, which apparently helps with cooling and performance or something that probably only matters in Downhill MTB.
Floating discs in most applications actually do float. It's news to me that they don't on a bicycle wheel. I shall research it!
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Is the float supposed to be tangible to the finger or do they only float under braking pressure?
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Interesting, thanks! :thumbsup:
Now I know which rotor brand to go for. Hadn't occured to me to look at Campagnolo. Just got to check that there aren't compatibility issues, but he seems confident using them with Shimano calipers. Got a bit scared when he started talking about heat transferring into the hubs, boiling your bearing grease, and expanding the hub shell but I suppose that is more likely on mountainous terrain rather than the short descents we have here. I've never knocked mine out of true either, despite many trips in the car, just that annoying scraping or pinging sound after prolonged braking.
How many discs did he say he gets through in a year? :o
My pleasure - it's a great channel. I'm an engineer too, albeit software, but really interested in the mechanical properties of metal, which is his day job. I love it when he pokes hole in cycling marketing bollox with a big stick of maths.
I think he lives in Malaysia now - so he has some pretty big hills, it is very warm, and very wet: He says the wetness, and more the road grit it brings onto the pads, accelerates wear significantly.
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Is the float supposed to be tangible to the finger or do they only float under braking pressure?
The disc should be mounted on pins half connected to the spider - this is what allows a little bit of float. I don't have a bicycle floating disc in front of me to check - but that is how they work on my motorbike.
The motorbike pins don't move under finger pressure - and I wouldn't expect the bicycle ones too either AND I would be worried about warping: They are so thin!
The theory is rather than bending your disk towards the pads - everything stays in the same plane, which gives the pads the greatest surface area to operate even when new: Rather than being slowly chamfered to match the slight angle of fixed disks being bent a little under the force of the callipers slightly offset to the actual centre of the disk.
This would have been better described with a picture ;D
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Interesting, thanks! :thumbsup:
Now I know which rotor brand to go for. Hadn't occured to me to look at Campagnolo. Just got to check that there aren't compatibility issues, but he seems confident using them with Shimano calipers. Got a bit scared when he started talking about heat transferring into the hubs, boiling your bearing grease, and expanding the hub shell but I suppose that is more likely on mountainous terrain rather than the short descents we have here. I've never knocked mine out of true either, despite many trips in the car, just that annoying scraping or pinging sound after prolonged braking.
How many discs did he say he gets through in a year? :o
My pleasure - it's a great channel. I'm an engineer too, albeit software, but really interested in the mechanical properties of metal, which is his day job. I love it when he pokes hole in cycling marketing bollox with a big stick of maths.
I think he lives in Malaysia now - so he has some pretty big hills, it is very warm, and very wet: He says the wetness, and more the road grit it brings onto the pads, accelerates wear significantly.
That makes sense. Those conditions melt everything. There was an Australian guy talking about common failure of HT2 cranks, (cue anxiety for me) but it turns out its really only happening in the southern hemisphere.
I've seen some PeakTorque vids, mainly last year when I had just bought a Supersix HiMod, was googling reviews and found him reviewing his. Agree with you about him lambasting marketing bollocks. I much prefer him to Hambini because his ego doesn't seem to come into things.
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Is the float supposed to be tangible to the finger or do they only float under braking pressure?
The disc should be mounted on pins half connected to the spider - this is what allows a little bit of float. I don't have a bicycle floating disc in front of me to check - but that is how they work on my motorbike.
The motorbike pins don't move under finger pressure - and I wouldn't expect the bicycle ones too either AND I would be worried about warping: They are so thin!
The theory is rather than bending your disk towards the pads - everything stays in the same plane, which gives the pads the greatest surface area to operate even when new: Rather than being slowly chamfered to match the slight angle of fixed disks being bent a little under the force of the callipers slightly offset to the actual centre of the disk.
This would have been better described with a picture ;D
That's actually very clear, thanks.
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Floating discs on motorbikes are exactly as trundle describes. The disc itself 'floats' on the bobbins that connect it to the bell, spider or cage that is fixed to the hub, and the bobbins allow a small amount of lateral movement of the disc to ensure that the braking effort is applied equally by the pistons on either side of the calliper. A cheaper setup allows a single-piston calliper to apply a balanced pressure to the disc. The float is often quite noticeable, particularly on racing discs which will often rattle on the bobbins. An alternative way of achieving centralised pressure is a floating calliper, which is kind of similar to the way a single-pivot rim brake (should) avoid distorting a wheel under braking. The two-piece construction is about heat dissipation.
When I raced in karting (250 ICE, for those in the know), the discs floated on the axles using a connector not dissimilar to the Shimano centrelock system, and again the movement was distinct and sometimes noisy. Hence my assumption that they worked on a similar principle on bikes. But, looking closely, it appears that there's a compressible washer on the bobbins that allows a tiny amount of lateral movement on the spider and, as trundle says, it's not detectable by finger pressure - and floating disc of this type are available on both 6-bolt and centrelock mounts.
I have my doubts that this kind of float is particularly worthwhile on a bicycle (I think the hydraulic balance in the calliper will do all the self-centring needed), or that the heat dissipation properties of Icetech Freeza rotors are needed for most YACF-style riders. But they look nice, and often that's all that's needed!
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I have my doubts that this kind of float is particularly worthwhile on a bicycle (I think the hydraulic balance in the calliper will do all the self-centring needed), or that the heat dissipation properties of Icetech Freeza rotors are needed for most YACF-style riders. But they look nice, and often that's all that's needed!
You are spot on with the hydraulic self-centering with dual piston callipers :thumbsup:
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... or that the heat dissipation properties of Icetech Freeza rotors are needed for most YACF-style riders. But they look nice, and often that's all that's needed!
Don’t forget the m in half m v squared.
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... or that the heat dissipation properties of Icetech Freeza rotors are needed for most YACF-style riders. But they look nice, and often that's all that's needed!
Don’t forget the m in half m v squared.
Have to say that occurred to me too, but I was more charitable;)
Or perhaps the v being squared more than compensates (other than on the hills...)
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An alternative way of achieving centralised pressure is a floating calliper
You could do this by forgetting to tighten the mounting bolts after you've loosened them slightly to centre them on the disc.
I may have done this accidentally once. Or twice...
NB not a serious recommendation.
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I had a total loss of braking mid way through a January 200 using Juin-Tech cable/hydro hybrids (a bit like a cheap rip off of the TRP hybrid ones). Both brakes. They had been an absolute bugger to set up, and I had been having to adjust them mid ride, every ride.
...
Brakes went in the bin. Never really got to the bottom of the issue, but lost faith in them.
That sounds pretty alarming.
I’ve found they set up easily enough and don’t need much attention, so far. But I suspect I go less far than you.
For me the advantage was in the levers. But I’m picky about them.
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... or that the heat dissipation properties of Icetech Freeza rotors are needed for most YACF-style riders. But they look nice, and often that's all that's needed!
Don’t forget the m in half m v squared.
As a heavier-than-average rider, I never forget it!
Talking of motorcycle floating discs, my brother turned up at my house this afternoon on his new BMW RS1250R. It was definitely possible to move the discs on the bobbins, so I think that the 'floating' description of the Shimano discs is perhaps stretching the truth.
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Floating discs on motorbikes are exactly as trundle describes. The disc itself 'floats' on the bobbins that connect it to the bell, spider or cage that is fixed to the hub, and the bobbins allow a small amount of lateral movement of the disc to ensure that the braking effort is applied equally by the pistons on either side of the calliper. A cheaper setup allows a single-piston calliper to apply a balanced pressure to the disc. The float is often quite noticeable, particularly on racing discs which will often rattle on the bobbins. An alternative way of achieving centralised pressure is a floating calliper, which is kind of similar to the way a single-pivot rim brake (should) avoid distorting a wheel under braking. The two-piece construction is about heat dissipation.
When I raced in karting (250 ICE, for those in the know), the discs floated on the axles using a connector not dissimilar to the Shimano centrelock system, and again the movement was distinct and sometimes noisy. Hence my assumption that they worked on a similar principle on bikes. But, looking closely, it appears that there's a compressible washer on the bobbins that allows a tiny amount of lateral movement on the spider and, as trundle says, it's not detectable by finger pressure - and floating disc of this type are available on both 6-bolt and centrelock mounts.
I have my doubts that this kind of float is particularly worthwhile on a bicycle (I think the hydraulic balance in the calliper will do all the self-centring needed), or that the heat dissipation properties of Icetech Freeza rotors are needed for most YACF-style riders. But they look nice, and often that's all that's needed!
250 ICE, that's a gearbox class isn't it?
So fast that most tracks had a straighter bit for you that was rather unimaginatively known as "the gearbox straight"
I don't remember many meets with anything faster than JICA or Senior TKM.
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Also when I said "doesn't really float" the movement in pins was what I was meaning.
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Floating discs on motorbikes are exactly as trundle describes. The disc itself 'floats' on the bobbins that connect it to the bell, spider or cage that is fixed to the hub, and the bobbins allow a small amount of lateral movement of the disc to ensure that the braking effort is applied equally by the pistons on either side of the calliper. A cheaper setup allows a single-piston calliper to apply a balanced pressure to the disc. The float is often quite noticeable, particularly on racing discs which will often rattle on the bobbins. An alternative way of achieving centralised pressure is a floating calliper, which is kind of similar to the way a single-pivot rim brake (should) avoid distorting a wheel under braking. The two-piece construction is about heat dissipation.
When I raced in karting (250 ICE, for those in the know), the discs floated on the axles using a connector not dissimilar to the Shimano centrelock system, and again the movement was distinct and sometimes noisy. Hence my assumption that they worked on a similar principle on bikes. But, looking closely, it appears that there's a compressible washer on the bobbins that allows a tiny amount of lateral movement on the spider and, as trundle says, it's not detectable by finger pressure - and floating disc of this type are available on both 6-bolt and centrelock mounts.
I have my doubts that this kind of float is particularly worthwhile on a bicycle (I think the hydraulic balance in the calliper will do all the self-centring needed), or that the heat dissipation properties of Icetech Freeza rotors are needed for most YACF-style riders. But they look nice, and often that's all that's needed!
250 ICE, that's a gearbox class isn't it?
So fast that most tracks had a straighter bit for you that was rather unimaginatively known as "the gearbox straight"
I don't remember many meets with anything faster than JICA or Senior TKM.
Sent from my BKL-L09 using Tapatalk
Yes, single-cylinder 7-speed. Mostly Rotax, some Yamaha. About 80 bhp and 135mph. I raced mostly long circuit stuff.
(https://i.imgur.com/bLFGWTn.jpg)
My last ever race meeting, Snetterton March 1996.