Least offensive looking 57mm dual pivots for 80's frame

[Brucey]

FWIW the best SP brakes have a caliper MA of about 1:1 (but this of course will vary with where the brake blocks end up in the slot) and Gen 1 DPs have an MA of about 1.25:1 (ditto for varying too). This is a big difference! Older weinmann side pulls and the like didn't have anywhere near a 1:1 MA unless the brake blocks were in the top of the slot and even then the arms were a bit flexy.

Pre 2008 DP levers run a different MA to SP levers and use a slightly lower cable tension, but the overall system MA with DPs is typically still about 15% more than with a good SP setup. If you run a DP caliper with an SP lever then you will get more brake power (which might well make up for various other systematic deficiencies... but otherwise arguably be too much) at the expense of running clearance.

There were of course several different Dura-Ace SP calipers but there was a massive step forward when 7400 was introduced. These brakes have ball-bearing pivots, stiff arms and a good MA. You can make them a bit feebler by fitting them to a frame which uses all the reach but when paired with the correct levers they are excellent brakes. Earlier DA brakes were a bit feeble by comparison.

All this talk of 'all SP brakes being a bit crap' is basically nonsense; BITD crappy systems certainly abounded (and remember they usually didn't even have cables with liners in back then... ) but when set up correctly Campag NR, DA 7400, BR-1050 etc are all excellent brakes by any standards. People who have faint/flawed memories of these systems should try a correctly set up system of that type with modern cables and brake blocks etc before dismissing them and just parroting how wonderful DPs are.....

BTW a significant advantage for SP brakes in real-world/racing conditions is that should a wheel go out of shape, an SP brake will rub but still 'follow the wheel' (i.e. swing from side to side), thus allowing a choice of 'no brake' (with the QR wide open) or a working brake with some drag. DPs and other fixed calipers don't give the same options, because when fixed arms rub, they rub hard.

cheers

[Samuel D]

FWIW the best SP brakes have a caliper MA of about 1:1 (but this of course will vary with where the brake blocks end up in the slot) and Gen 1 DPs have an MA of about 1.25:1 (ditto for varying too). This is a big difference!

That difference would certainly be noticeable, but I get the impression from people’s comments that it’s not big enough to explain the perceived difference in braking performance.

I’d like to try an unlined cable housing with a greased cable, just to see how that performs compared to the modern options. Suitably greased metal on metal should be alright, surely? But in the absence of grease and presence of corrosion – perhaps the typical condition – performance would fall off a cliff.

[pwa]

Brucey's experience of single pivot Shimano 105 calipers does not match mine. i remember cursing them on a tour of France in about 1987 where about twice daily I'd adjust to get rubbing blocks away from the rims. The 105 dual pivots that came a few years later seemed to me to be the start of decent brakes on bicycles. That extra 80g or so was made up for by lack of rub.

[JohnW]

..............I’d like to try an unlined cable housing with a greased cable, just to see how that performs compared to the modern options. Suitably greased metal on metal should be alright, surely? ...............

In my memory, the drawback of using unlined cable outers was in the release of the brakes, not in the application. Maintenance and corrosion avoidance was certainly an issue, but so long as I greased cables properly when assembling, and cleaned and re-greased at intervals, I didn't have problems..............once I'd learned the virtue of doing it!

[djnotts]

".... centre-pulls, which were a sign of quality and strength in comparison to flimsy side-pulls back in the day.

There wasn't actually much wrong with their basic design which better shoes and blocks wouldn't have cured...."

When I used to fit 700c wheels in frames built for 27"ers, long centre pulls worked well with "long" V brake blocks. Certainly MUCH better than side pulls from same period. The currently available DiaCompe (?) centre pulls look lovely and I'm sure work fine.

[meic]

I tried the long cente-pulls that came with my (originally 27") bike with a variety of pads but they never worked satisfactorily. Fitting cheap Alhonga dual pivot deep reach calipers was an enormous improvement.

[Brucey]

Brucey's experience of single pivot Shimano 105 calipers does not match mine. i remember cursing them on a tour of France in about 1987 where about twice daily I'd adjust to get rubbing blocks away from the rims..

I've seen this often. Invariably it boils down to a setup or maintenance issue of some kind. BTW folk mither about SP brake centring but will happily tolerate (say) V brakes which are often a deal more trouble in this respect....

..............I’d like to try an unlined cable housing with a greased cable, just to see how that performs compared to the modern options. Suitably greased metal on metal should be alright, surely? ...............

In my memory, the drawback of using unlined cable outers was in the release of the brakes, not in the application....

IME if the cable gets draggy enough that the brake won't return, then it has been silently robbing you of a good fraction of your braking effort for months (at least) beforehand. A good feature of unlined housings is that they can be impregnated with grease, such that they will work for years without further attention (if you use the right grease). But at their best they do not work as well as housings with liners, and the result is reduced brake power and worse modulation vs a fresh linered cable.

I tried the long cente-pulls that came with my (originally 27") bike with a variety of pads but they never worked satisfactorily. Fitting cheap Alhonga dual pivot deep reach calipers was an enormous improvement.

Centre pulls are subject to similar caveats as cantis; they develop their best mechanical advantage only when the straddle geometry is correct, they need good hangers, good cables, and if you try and use the wrong brake (eg a long arm version) with the wrong levers (eg those made for DPs) they will lose power that way too.

By contrast DPs are 'difficult to get wrong' and you don't fit them (to a bike that had CPs originally) without fitting new (better) cables and (likely) brake blocks as well. So it is easy to blame the difference on the obvious thing (the appearance of the brake) rather than the actual things (which could be different to that).

".... centre-pulls, which were a sign of quality and strength in comparison to flimsy side-pulls back in the day......"There wasn't actually much wrong with their basic design which better shoes and blocks wouldn't have cured..."
When I used to fit 700c wheels in frames built for 27"ers, long centre pulls worked well with "long" V brake blocks. Certainly MUCH better than side pulls from same period. The currently available DiaCompe (?) centre pulls look lovely and I'm sure work fine.

Indeed they do. FWIW CP calipers do (of course) vary but they can have the same (or better) MA as a DP brake. I still have CPs fitted to a touring machine and they work very well.

The problem with many 'upgrades' is that

a) the upgradee will want to self validate (emporer's new clothes if you like) and
b) the comparison is rarely a fair one; shiny newness is being compared with broken, worn, maladjusted, mismatched stuff and the difference in performance is attributed to anything but the fact that the old stuff was knackered in some way.

cheers

[pete75]

In period would be Weinmann Dynamic

[JohnW]

...........................

..............I’d like to try an unlined cable housing with a greased cable, just to see how that performs compared to the modern options. Suitably greased metal on metal should be alright, surely? ...............

In my memory, the drawback of using unlined cable outers was in the release of the brakes, not in the application....

IME if the cable gets draggy enough that the brake won't return, then it has been silently robbing you of a good fraction of your braking effort for months (at least) beforehand.....................

Hmm - if there's friction in the cable then I'd say that we simply squeeze the lever a bit harder - we apply as much pressure to lever as necessary to apply the brakes as hard as we wish. There's a helluva lot of friction in the cable to defeat us in that. We have control over the amount of pressure we put on, but we've no control over the strength of the return spring. I've certainly had the experience of brakes not releasing properly and not having realised the amount of friction developed in the cable.

[JohnW]

In period would be Weinmann Dynamic

Now those ARE brake-blocks!!!

[Brucey]

Hmm - if there's friction in the cable then I'd say that we simply squeeze the lever a bit harder - we apply as much pressure to lever as necessary to apply the brakes as hard as we wish. There's a helluva lot of friction in the cable to defeat us in that. We have control over the amount of pressure we put on, but we've no control over the strength of the return spring. I've certainly had the experience of brakes not releasing properly and not having realised the amount of friction developed in the cable.

sure... but ultimately there is a limit to how hard folk can (or are prepared to) squeeze the brake lever, hence 'x-type brakes are crap' comments and so forth. When you can't lock the rear brake (even when the front is on, and the rear wheel is unloaded so ought to lock easily) then you can only conclude that most of whatever effort you are putting in at the lever must be going AWOL en route...

BTW the return spring only ever has to pull the cable through the housing at relatively low tension. This is not always a good guide to how much effort is lost during braking because the friction coefficient isn't always anywhere near linear.

cheers

[JohnW]

Hmm - if there's friction in the cable then I'd say that we simply squeeze the lever a bit harder - we apply as much pressure to lever as necessary to apply the brakes as hard as we wish. There's a helluva lot of friction in the cable to defeat us in that. We have control over the amount of pressure we put on, but we've no control over the strength of the return spring. I've certainly had the experience of brakes not releasing properly and not having realised the amount of friction developed in the cable.

sure... but ultimately there is a limit to how hard folk can (or are prepared to) squeeze the brake lever, hence 'x-type brakes are crap' comments and so forth. When you can't lock the rear brake (even when the front is on, and the rear wheel is unloaded so ought to lock easily) then you can only conclude that most of whatever effort you are putting in at the lever must be going AWOL en route...

BTW the return spring only ever has to pull the cable through the housing at relatively low tension. This is not always a good guide to how much effort is lost during braking because the friction coefficient isn't always anywhere near linear.

cheers

An occasion that happened some years ago, and I've only just remembered, has occurred to me - it may endorse what Brucey is saying to a certain extent.

On a club-run, probably 35 years ago now, one of our section was complaining about his brakes. Certainly he wasn't stopping quickly enough. At some stage in the ride, someone asked him if he was pulling hard enough on his levers. He pulled really hard, locked both wheels and head-firsted into a mud-bath in a ditch (lucky it wasn't the tarmac).We took a look at his brakes and could hardly believe how stiff they were - his cables had been sticking and he'd been afraid to use brute force.

In those days, along with enough tools to fit everything except head-sets and BBs, some of us took little squeezy bottles of oil.

We took his brake cables off and separated them - the corrosion (it wasn't rust) and other blockages were incredible. We wiped his inner cables clean and someone filled the inners with the oil. On reassembly, the brakes worked a treat - he couldn't credit the difference.

Shortly after that the nylon tube inner sleeves became available. Good stuff them.

[Roadster]

Surely good quality, well-lubricated cables are prerequisite regardless of caliper design, closely followed by shoes and especially blocks. Only after these have been attended to can we even begin to discuss the relative merits of different types and manufacturers of brake mechanisms.

Compared to modern cables and brake blocks, those fitted to the Weinmann centre-pulls on my old Holdsworth Mistral tourer were pretty poor yet I thought at the time that the brakes were pretty good. I never even thought about their quality or lack thereof, but rode merrily around the Pennines, Lakes, Dales, South of France and Brittany without even questioning, let alone doubting, their efficacy.

I lived to tell the tale, which leads me to believe that unless you ride really fast or really heavily laden, any perceived deficiencies in braking are unlikely to be due to the design of the actual calipers themselves.

[Brucey]

Surely good quality, well-lubricated cables are prerequisite regardless of caliper design, closely followed by shoes and especially blocks. Only after these have been attended to can we even begin to discuss the relative merits of different types and manufacturers of brake mechanisms.

yes sure, hence my earlier suggestion that trying old brakes (with the correct levers) with new cables and brake blocks would be a fair test. As it is many people have distant memories that of systems that could be on the one hand rose tinted, and on the other tainted by the differences in these consumable items.

Compared to modern cables and brake blocks, those fitted to the Weinmann centre-pulls on my old Holdsworth Mistral tourer were pretty poor yet I thought at the time that the brakes were pretty good. I never even thought about their quality or lack thereof, but rode merrily around the Pennines, Lakes, Dales, South of France and Brittany without even questioning, let alone doubting, their efficacy.

I lived to tell the tale, which leads me to believe that unless you ride really fast or really heavily laden, any perceived deficiencies in braking are unlikely to be due to the design of the actual calipers themselves.

well, not entirely I think there are two things going on;

1) what happens is that you learn to ride within the limitations of the brakes you have. I've ridden bikes where I knew that -with a load on in the wet especially- I didn't want to go too fast in certain places because I would not be able to stop in a reasonable distance or indeed at all.

2) FWIW Weinmann CPs had a fairly high MA; they were decent stoppers, especially if the short (610) model was used around 55mm drop or so, and somewhat less so at longer reaches (the 750 model did not have an increased upper arm length, so lost MA pro-rata with reach; a 610 model caliper at 50mm reach would be about half as good again as a 750 model at 75mm reach). By comparison an equivalent reach/vintage weinmann side-pull brake might well have terrified you (or worse). Both work quite a bit better with modern consumable parts.

cheers