Author Topic: Let's talk Hydraulic brakes  (Read 2061 times)

quixoticgeek

  • Mostly Harmless
Let's talk Hydraulic brakes
« on: January 19, 2020, 08:21:52 pm »

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
--
Beer, bikes, and backpacking
http://b.42q.eu/

Re: Let's talk Hydraulic brakes
« Reply #1 on: January 19, 2020, 08:55:22 pm »
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.

Re: Let's talk Hydraulic brakes
« Reply #2 on: January 19, 2020, 08:57:30 pm »
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.

Re: Let's talk Hydraulic brakes
« Reply #3 on: January 19, 2020, 09:26:50 pm »
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.

fuaran

  • rothair gasta
Re: Let's talk Hydraulic brakes
« Reply #4 on: January 19, 2020, 09:44:54 pm »
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.

Torslanda

  • Professional Gobshite
  • Just a tart for retro kit . . .
    • John's Bikes
Re: Let's talk Hydraulic brakes
« Reply #5 on: January 19, 2020, 09:51:47 pm »
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.

VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

Re: Let's talk Hydraulic brakes
« Reply #6 on: January 19, 2020, 10:03:13 pm »
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.
If you don’t make time for exercise now, sooner or later you’ll need to make time for ill health.

Re: Let's talk Hydraulic brakes
« Reply #7 on: January 19, 2020, 10:12:39 pm »
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
If you don’t make time for exercise now, sooner or later you’ll need to make time for ill health.

LMT

Re: Let's talk Hydraulic brakes
« Reply #8 on: January 19, 2020, 10:33:48 pm »
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.

bludger

  • Randonneur and bargain hunter
Re: Let's talk Hydraulic brakes
« Reply #9 on: January 19, 2020, 10:42:43 pm »
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.
YACF touring/audax bargain basement:
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Re: Let's talk Hydraulic brakes
« Reply #10 on: January 19, 2020, 11:11:53 pm »
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.
Most of the stuff I say is true because I saw it in a dream and I don't have the presence of mind to make up lies when I'm asleep.   Bryan Andreas

FifeingEejit

  • Not Small
Re: Let's talk Hydraulic brakes
« Reply #11 on: January 19, 2020, 11:21:43 pm »
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.

Re: Let's talk Hydraulic brakes
« Reply #12 on: January 20, 2020, 06:39:43 am »
Avoid DOT 5.1 systems and anything without provision for fluid expansion.
Never tell me the odds.

ElyDave

  • Royal and Ancient Polar Bear Society member 263583
Re: Let's talk Hydraulic brakes
« Reply #13 on: January 20, 2020, 06:52:02 am »
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.
“Procrastination is the thief of time, collar him.” –Charles Dickens

Re: Let's talk Hydraulic brakes
« Reply #14 on: January 20, 2020, 07:00:47 am »
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.

ElyDave

  • Royal and Ancient Polar Bear Society member 263583
Re: Let's talk Hydraulic brakes
« Reply #15 on: January 20, 2020, 07:35:10 am »
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?
“Procrastination is the thief of time, collar him.” –Charles Dickens

bludger

  • Randonneur and bargain hunter
Re: Let's talk Hydraulic brakes
« Reply #16 on: January 20, 2020, 07:43:10 am »
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.
YACF touring/audax bargain basement:
https://bit.ly/2Xg8pRD


ElyDave

  • Royal and Ancient Polar Bear Society member 263583
Re: Let's talk Hydraulic brakes
« Reply #17 on: January 20, 2020, 07:45:36 am »
I was thinking more about the reduced cabin pressure,
“Procrastination is the thief of time, collar him.” –Charles Dickens

Re: Let's talk Hydraulic brakes
« Reply #18 on: January 20, 2020, 08:29:14 am »
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.

Re: Let's talk Hydraulic brakes
« Reply #19 on: January 20, 2020, 08:57:55 am »
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.

LittleWheelsandBig

  • Whimsy Rider
Re: Let's talk Hydraulic brakes
« Reply #20 on: January 20, 2020, 09:32:28 am »
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...
Wheel meet again, don't know where, don't know when...

Re: Let's talk Hydraulic brakes
« Reply #21 on: January 20, 2020, 09:46:48 am »
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. 

Re: Let's talk Hydraulic brakes
« Reply #22 on: January 20, 2020, 09:51:27 am »
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.

Re: Let's talk Hydraulic brakes
« Reply #23 on: January 20, 2020, 10:28:18 am »
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/

bludger

  • Randonneur and bargain hunter
Re: Let's talk Hydraulic brakes
« Reply #24 on: January 20, 2020, 10:35:38 am »
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.
YACF touring/audax bargain basement:
https://bit.ly/2Xg8pRD