Single-pivot sidepull callipers in 2017 (and beyond)

[Samuel D]

Recently I adjusted the brake pad height on the short arm of my Shimano BR-R650 due to pad wear. I need to do this finicky job every few months: once when the pad wears substantially and again when I install a new pad.

Compounding this nuisance, the front and rear pads wear at different rates, so I can’t even do them at the same time and be done with them.

Woe, I know.

Ideally I’d replace the cable housings too, but since they’re under the bar tape I can’t be bothered.

Single-pivot brakes would fix the pad adjustment problem, and non-aero levers would fix the cable access. Which got me thinking:

Which single-pivot brakes are good, and how good is that? I like the look of Rogerzilla’s BR-6400 and Sheldon Brown’s favourite-ever BR-1050. But also silly things like antique Campagnolo.

Writing in 1998, Sheldon Brown said this about Campagnolo Record brakes: “The construction and design of the Campagnolo levers differed from the best of previous models as a Cannondale differs from a Huffy.” Maybe that explains the prices on eBay.

Anyone beside Rogerzilla still favouring the single-pivot?

[LittleWheelsandBig]

My Frezoni has the last version of Dura-Ace single pivot brakes with Koolstop pads. I've never felt the need for anything more powerful.

[Samuel D]

That Dura-Ace model (BR-7400) was the last without a thrust ball bearing at the pivot, so it’s interesting you find them adequate anyway.

I’d need something with longer reach, somewhere near the middle of the standard 47–57 mm. I think you have to go back to the BR-7210 to find a Dura-Ace calliper with that sort of reach.

Which brings me to a couple of questions:

• Is there any way to safely run externally nutted brakes on a recessed frame and fork?
• Why did the industry move from external hex nuts to recessed Allen-key nuts anyway? That change made it harder to add and remove mudguards, as I often do since I have a single bicycle.
• Can modern Shimano cables and housings be used with classic Campagnolo brakes? I suspect this would improve their performance if possible, and the shorter life of SLR housing would be tolerable if the cables were easily accessible for replacement.

[Brucey]

you can drop a suitably sized washer/spacer into the recess and use nutted brakes quite easily.  At one time some models of brake block came with a shouldered nut that was ideal for this purpose.

The fashion for running (more powerful, neater) short reach brakes on road-racing bikes (mid '70s onwards; Campag didn't even bother doing a 'piccolo' brake to start with) meant that mudguards were not part of the thinking anyway; it was only a short step to allen key fittings from there.

DA 7200 series brakes were good in their day but in long reach form I think you would find them somewhat flexy and (like many other SP brakes) the sidearms were not always proportionately longer, so MA wasn't up to the same levels as shorter reach brakes, if you actually needed the extra reach.

FWIW if brake adjustments are your main beef, it might be easier just to use  rims that have deeper braking surfaces.

BTW if you run exposed cable levers (such as BL-1050) with a first generation DP caliper (set to almost full reach) then the brakes will be pretty good; plenty of power etc.

cheers

[Cudzoziemiec]

I've never done it but I'm reliably informed it's fairly simple to thread new cables through in-situ outers under the bar tape.

As for single-pivot versus dual-pivot, I've never quite understood it, though I did read a good summary of the differences. Might have been on Sheldon? Anyway, when I got my first bike with dps, I asked about the difference and the shop owner wasn't able to explain either...

[Brucey]

re the difference between DPs and SPs there is a higher caliper MA in DPs.  In good part because the MA and running clearance vary with brake block setting in the slots anyway, various combinations of lever and caliper that are 'wrong' may actually work OK.

A good part of the move to DPs was due (I think) to the caliper centring issues with SP brakes.  With exposed cables the occasional bike would manifest a bad cable routing (eg that would ratchet the rear housing through the guides, eventually pulling the brake on, or have a bad front cable run that would shift the brake) but these were not show-stoppers.  The usual source of SP brake centring issues was bad installation and maintenance.

However with the advent of aero levers, things changed; first the rear cable housing run was more likely to be tugged as the bars turned and second the front brake housing run was also very short (esp on small frames) and this meant that the brake centring would often be problematic. It wasn't at all unusual to have to adjust the brake centring as the brake blocks wore on some bikes.

Even so it wasn't impossible to set SP caliper systems, but  DP calipers immediately meant that anyone would be able to set the brakes up to work relatively easily. Also when the brakes got covered in crud, and started not to work properly, they were less likely to start dragging badly. Most folk were happier with DPs.

However when I built myself up a nice road bike a few years ago, I didn't bother with the DP brakes that came with the groupset; I fitted some NOS BR-1050 calipers that I had kicking around instead. Despite the MA mismatch, with the right brake blocks fitted, they were powerful enough for me, and they were a lot lighter in weight, too; at the time they were lighter than pretty much any DP brake that didn't use Ti hardware, IIRC.

cheers

[Biggsy]

Even with rims with narrow brake tracks, I don't need to adjust the blocks with DPs as the pads wear - I suppose because my (Koolstop Dura) pads are narrow and shallow and I don't mind if they end up very slightly hanging over the top or bottom of the track, as long as they'll never foul the tyre, of course.  I tend to replace the pads before they're completely finished anyway.

Regarding the choice between DP and SP: a reasonable compromise is DP front and SP rear.  Personally, I would never give up the mechanical advamtage of DP on the front just for the relatively minor benefits of SP, but I do have an SP rear on my lightest bike.  I could have got a Campag "Differential" set but chose some other (forgotten) obscure make of rear caliper to get quick-release, which Campag don't bother wth.  (Campag instead puts an opening function in the Ergo levers, but it's nice to get some further clearance).

[LittleWheelsandBig]

That Dura-Ace model (BR-7400) was the last without a thrust ball bearing at the pivot, so it’s interesting you find them adequate anyway.

I’d need something with longer reach, somewhere near the middle of the standard 47–57 mm. I think you have to go back to the BR-7210 to find a Dura-Ace calliper with that sort of reach.

Which brings me to a couple of questions:

• Is there any way to safely run externally nutted brakes on a recessed frame and fork?
• Why did the industry move from external hex nuts to recessed Allen-key nuts anyway? That change made it harder to add and remove mudguards, as I often do since I have a single bicycle.
• Can modern Shimano cables and housings be used with classic Campagnolo brakes? I suspect this would improve their performance if possible, and the shorter life of SLR housing would be tolerable if the cables were easily accessible for replacement.

I have a strong handshake, so braking power is fine with any decent set of brakes and pads.

If you can find Dia-Compe's Royal Gran Compe in 500 reach, they match my Dura-Ace for stiffness and power. I had a set of the RGC400 in the limited edition black and gold (plated) finish and they were very good.
https://www.bike-vintage.com/brakes-calipers/982-dia-compe-royal-gran-compe-400-front-brake-caliper-gold-edition-new-nos.html

Allen key bolts were 'new and modern' and matched the other fasteners on bikes that were switching away from normal bolts/ nuts.

I've always used lined cables (Dia-Compe, Shimano SLR or whatever) for brakes, regardless of the caliper age. There is no benefit in metal scraping on metal.

[Samuel D]

The fashion for running (more powerful, neater) short reach brakes on road-racing bikes (mid '70s onwards; Campag didn't even bother doing a 'piccolo' brake to start with) meant that mudguards were not part of the thinking anyway; it was only a short step to allen key fittings from there.

Using an Allen key is convenient on a bicycle with those fasteners elsewhere, but the recessed part means removing the calliper to fit or remove a mudguard. You need three hands for that job, and mounting the mudguard on the brake side also means the callipers slightly change position when mudguards are added or removed, aggravating any positioning error of the pads.

(A washer in place of the absent mudguard bracket would fix that, but since I only have about 4 threads of nut engagement, I try to improve engagement when mudguards aren’t there. The next longer Shimano nut (going from 18 mm to 27 mm) is too long; I’ve tried it.)

I've never done it but I'm reliably informed it's fairly simple to thread new cables through in-situ outers under the bar tape.

Aye. It’s the outers that concern me. These have tight curves (aero brake levers) and plastic liners (Shimano SLR), so they don’t last forever.

With exposed cables the occasional bike would manifest a bad cable routing (eg that would ratchet the rear housing through the guides, eventually pulling the brake on

Dave Moulton describes a trick for that here. Maybe you know it.

Even with rims with narrow brake tracks, I don't need to adjust the blocks with DPs as the pads wear - I suppose because my (Koolstop Dura) pads are narrow and shallow and I don't mind if they end up very slightly hanging over the top or bottom of the track, as long as they'll never foul the tyre, of course.  I tend to replace the pads before they're completely finished anyway.

I don’t like the pad hanging off the track even slightly, partly because things get messy under hard braking when the calliper arms bend. Plus, it’s borderline unsafe and ugly. In fact, the inelegance of the pad height varying with wear is half of my objection! And I use up the whole pad before replacing them, since they’re kind of expensive and I ride in all weather.

Thanks for the interesting discussion, all. May I draw your attention to question 3 here. Merci !

[Samuel D]

I've always used lined cables for brakes, regardless of their age. There is no benefit in metal scraping on metal.

I have 35-odd metres of Shimano SLR housing in a big roll. I’d like to use specifically that housing with any future brakes. Would it work with Campagnolo Record brakes from decades ago? This page shows a small difference in cable head design and says, “A Shimano cable head is slightly larger than a Campy head so it may not fit into a Campy road brake”. I wonder if the housing is also slightly different.

[dat]

I prefer non-aero brake levers for feel and ease of changing out cables. I've just installed some NOS 1050 Shimano brake levers on a new build. Best brake levers I have found for non-aero feel.

[LittleWheelsandBig]

The housing is basically the same size, barring a handful of instances where I've had to strip the plastic off the spiral to get it to seat nicely in a cable stop. The heads on the inner cables are not fully interchangeable, though you can use Campag inner cables in Shimano brake levers.

I used to put a tiny ziptie around the rear brake cable (in a similar but faster manner to Moulton's O-ring) when the cable outer would inchworm through the cable eyelet.

[Brucey]

I'm a ziptie man myself. The other thing I've done is to put a few turns of tape onto the cable housing so that it becomes a wedged fit into the cable guide.

Original campag NR cable housing was larger diameter than modern stuff, about 5.5mm, (which, BTW, is why the sleeving occasionally needed to come off when fitting it into small receptacles).  New (typically ~5.0mm dia) housing fits old calipers and levers if the correct ferrules are used where necessary.

Cable inners can be had to fit campag, be 'universal' or be shimano compatible. The first two will fit OK and the third will need the ferrule to be filed slightly to be a good fit in a campag lever. There is small difference between the original campag inner diameter, modern campag inner and shimano inner cable, too.  However, anything you can buy new now will work inside pretty much all modern housing.

[Biggsy]

Replacing the pads early saves the need for any overhang, so then in practice it's just a question of economy as far as pad wear goes.  You'll still be bothered by the tiny weeny bit of ineligance, though.

Championing SPs reminds me of Jobst Brandt.  He was right about about the technicalities but incredibly dismissive when anyone said they prefered not to have to pull* the lever so hard.  It does come down to personal preference after all.

Classic campag calipers aren't very fussy about cables.  Sorry I don't know/remember enough about Shimano's to comment more specifically.

* or rather *push* from the hood position - something that Brandt never did himself - a less efficient but often more convenient way of using the lever for many riders.  I too wouldn't be so bothered about the MA if I only ever braked from the drops.

[DuncanM]

Campag made their Skeleton brakes in dual pivot front and single rear for ages.  Looks like they still do for Record (mine are just Veloce)!
http://www.chainreactioncycles.com/campagnolo-record-d-brakeset/rp-prod127558

[Samuel D]

or rather *push* from the hood position - something that Brandt never did himself - a less efficient but often more convenient way of using the lever for many riders.  I too wouldn't be so bothered about the MA if I only ever braked from the drops.

I did a few Google Groups searches for Jobst Brandt’s opinions on single-pivot brakes. You’re right, he didn’t spare the sarcasm for “avocational” riders with soft hands, some of whom even had the temerity to take up bicycling in middle age. (But boy did he do sarcasm well! His “Or everywhere!” here slew me.)

However, photos show Brandt did ride on the hoods and he claims he braked from there too, for example here. (I’m surprised he could see over the sea of black SUVs he despised.)

Arguing from another viewpoint, Sheldon Brown has some interesting thoughts on the advantages of aero levers here.

Google Groups is a treasure trove of information on bicycle technologies and how they were seen a couple of decades ago. Pity it’s so hard to search. Pity too that giants like Brown and Brandt are gone.

[Brucey]

Sheldon's comments on aero levers are worth reading for sure but

- the comment about less cable drag with aero levers is just wrong IME; there are more, tighter, bends, and more drag as a consequence.  If you like to have the front brake on the right side, the last bend onto a typical modern brake caliper (or a cable hanger for CP or canti brakes) can be particularly tight on smaller frames, and can result in a kink as the cable enters the caliper/hanger.

- yes the cables can be kinked and damaged where they enter the top of a non-aero lever, but this is mitigated by the damage being both obvious and easier to rectify.

- the argument about pivot positions is pretty spurious IMHO; pivot positions vary between levers of all types and with it (together with preference for lever position and angle) brake efficiency from the hoods will vary. Although with any one brand of lever there may be a difference, there is no clear intrinsic advantage for one type of lever over the other.

One of the insidious features of aero levers is that occasionally a (usually  badly-prepped) cable housing will start to bind on the cable where it exits the back of the lever. If you even suspect that this is the case, it is a pretty long-winded affair to determine that this is happening, and to fix it.

BTW it amazes me that no-one has come up with a re-usable, spliceable,  maybe washable, bar tape, that relies on stretching/friction (or Velcro?) to stay put on the handlebars. The amount of effort and technology that is devoted to other aspects of bicycle design is prodigious, yet something simple and practical like that appears to have been entirely overlooked....

If you think about it there are many other things that might be of real practical benefit to cyclists, but it seems that no-one in the industry has noticed, or is prepared to do anything about it if they have.

cheers

[jsabine]

Using an Allen key is convenient on a bicycle with those fasteners elsewhere, but the recessed part means removing the calliper to fit or remove a mudguard. You need three hands for that job, and mounting the mudguard on the brake side also means the callipers slightly change position when mudguards are added or removed, aggravating any positioning error of the pads.

Taking inspiration from Sheldon's FenderNuts, I tap the rear-facing end of the front brake nuts so I can attach the guards with an M6 screw. Avoids any unnecessary pissing about with brake position (though admittedly I rarely take the mudguards off anyway).

[Samuel D]

Good idea, jsabine.

the comment about less cable drag with aero levers is just wrong IME; there are more, tighter, bends, and more drag as a consequence.

There are more and tighter bends, but isn’t the more important factor the total angle through which the cable bends? That is what the formula for force transmitted by a cable on page 253 of the 3rd edition of Bicycling Science suggests, and I have seen some experiments (here and here) roughly backing that up.

If the total angle is what mainly matters, there might not be much difference in friction between new cables aero and non-aero. Just eyeballing it, what the non-aero set-up gains by not following the handlebar curves, it loses by having the cable exit the lever in an unfavourable direction (straight up).

The cables in the aero set-up will wear a groove into the liner sooner, because the curves are tighter and thus the forces higher. So however they start out, they won’t age as well as non-aero cables.

BTW it amazes me that no-one has come up with a re-usable, spliceable,  maybe washable, bar tape, that relies on stretching/friction (or Velcro?) to stay put on the handlebars. The amount of effort and technology that is devoted to other aspects of bicycle design is prodigious, yet something simple and practical like that appears to have been entirely overlooked....

If you think about it there are many other things that might be of real practical benefit to cyclists, but it seems that no-one in the industry has noticed, or is prepared to do anything about it if they have.

I guess there’s no money in fixing these things, mainly because most cyclists aren’t interested. Here’s what people are interested in. I encourage the reader to scroll through the 22 photos and captions and imagine this bicycle in common situations such as riding in the rain, washing it, hunting down a creak, loading it into a small car, installing new cable housings, buying new parts after a crash, buying new parts in five years, etc.

The bicycle reviewer’s capacity to ask the wrong questions never ceases to amaze me.

[Cudzoziemiec]

I'm not sure what exactly you mean by "hunting down a creak," I take it to refer to some sort of mild off-road, is that right?

But it's a matter of asking the right questions for the bike. I don't think the Madone is intended to appeal to people who do that sort of riding. Washing, replacing parts and general practicalities are barely more important than they would be to the owner of a Lamborghini.

[DuncanM]

I guess there’s no money in fixing these things, mainly because most cyclists aren’t interested. Here’s what people are interested in. I encourage the reader to scroll through the 22 photos and captions and imagine this bicycle in common situations such as riding in the rain, washing it, hunting down a creak, loading it into a small car, installing new cable housings, buying new parts after a crash, buying new parts in five years, etc.

The bicycle reviewer’s capacity to ask the wrong questions never ceases to amaze me.

That's essentially a wannabe racers bike. So it's got to be buzzword compliant, and look like the super top end bikes that the racers use, while being comfortable enough that the rider isn't thrown off and can finish group rides/sportives without too much bike induced pain. It's not for actual road racing (otherwise the stack would be lower), it's not for anything other than road (otherwise it would have better clearances), and it's not for anything as mundane as riding to work or servicing yourself.

Given the user requirements, what questions do you think the reviewer should be asking?

[Samuel D]

I meant creak the noise, not creek the waterway.

As with the Lamborghini, the aero Trek will be sold at fantastic price to people who don’t derive functional benefit from it, the benefits being anyway chiefly imaginary. It’s sold on an image of performance that is neither realistic nor relevant, while falling short in ways that matter to anyone who does more than a few miles here and there in sunshine. If it’s like the bicycles I see on the road, in a couple of years it will be a rattly, unsafe mess with several bodged repairs to keep bits of it from falling into the road. It will have an incongruous seatbag, assorted detritus on the handlebar, and maybe even an Ass Saver. At this time of year there will probably be lamps clumsily strapped front and rear.

The reviewer should ask what justifies this charade.

[Cudzoziemiec]

Those are questions which go way beyond any individual bike review and need to be posed to the bicycle industry as a whole. Probably mostly to customers. In fact, way beyond bikes.

[zigzag]

if there is a market, manufacturers will cater for it. if a mamil/wannabe racer is happier riding an aero pro bike lookalike with integrated brakes than do-it-all steel bike with single pivots, i don't see a problem. this also gives lbs's some business down the line.

[DuncanM]

As with the Lamborghini, the aero Trek will be sold at fantastic price to people who don’t derive functional benefit from it, the benefits being anyway chiefly imaginary. It’s sold on an image of performance that is neither realistic nor relevant, while falling short in ways that matter to anyone who does more than a few miles here and there in sunshine. If it’s like the bicycles I see on the road, in a couple of years it will be a rattly, unsafe mess with several bodged repairs to keep bits of it from falling into the road. It will have an incongruous seatbag, assorted detritus on the handlebar, and maybe even an Ass Saver. At this time of year there will probably be lamps clumsily strapped front and rear.

The reviewer should ask what justifies this charade.

And as with a Lamborghini, it's a vehicle designed neither for practicality, nor use in inclement weather, and the owner probably has another machine for winter.
I might as well point at this review: http://road.cc/content/review/66658-surly-disc-trucker and complain that it's slow, too upright, heavy, cumbersome handling, they have made every effort to make the frame and wheels as un-aero as possible, and it doesn't even have integrated brake levers and shifters. None of which matters, because it's a damn fine touring bike.

As for what state it will be in in a couple of years, that depends on who rides it and who maintains it. Generally, I don't tend to see 4 grand carbon bikes falling apart in the gutter - whenever I seen them they are clean and being ridden by club types. The ones falling apart in a state of disrepair tend to be £99 Cycle King student transport (though maybe Ofo/Pony will take that market). Maybe I'm just not observant enough, or maybe Oxford is weird.