Dura Ace 9000 brake calipers vs Paul Component Racer centre-pulls

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There’s been some head scratching on the configuration of the new Dura Ace 9000 brake caliper. Velonews speculated that there are 3 pivots hidden in the caliper above. What’s kind of weird is the spy photo from Japan (about a month old) seems to show a full production model, while the shots of Team Sky Pinarellos at the Giro this week have logo-free examples, as if they were prototypes. I would say that the new caliper most likely just has two pivots, but instead of Shimano’s previous (and widely copied) configuration of a central pivot and a secondary pivot, the DA9000 looks to have to equally spaced pivots. This would mean that the mounting bolt is not a pivot at all, that it simply holds a centre piece with a pivot at either end.

In essence, the DA9000 would be a cross between a centre-pull brake and a side-pull in that there are two pivots in roughly the same position as a short reach centre-pull, but the cable pulls along the side instead of having a straddle cable and yoke. Seen below is the Paul Components “Racer” centre-pull (from paulcomp.com)

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The similarities between the two also might explain the “direct mount” brake that Velonews discovered on a leaked tech document. Paul’s offers a “direct mount” version of the Racer which does away with the central bracket and instead mounts the two arms directly to a pair of brazed-on bosses, the arms pivoting there on. With a number of aero frame manufactures building bikes with integrated brakes, the DA9000 direct mount most likely has a similar purpose. However, bikes like the Willier Twin Foil that I have written about before have pivots that would not accommodate centre-pull-like brakes. The TRP brake that fit the Twin Foil are a variation of linear pull/cantilever arm brakes much like v-brakes, and the mounting boss sits below the rim’s sidewall (ie between the rim and the axle) rather than a centre-pull which has the boss above the rim. Also, I’m not sure how the cable arms and barrel adjuster would work on a rear brake, which on aero bikes is frequently jammed up behind the bottom bracket. Such as position would have the barrel adjust and the chainrings competing for the same space.



4 Comments

The last thing a rear brake needs to do is get fancy.

If Campy ever did anything right, it was with the simple, lightweight, single-pivot brake out back. On a road bike, its only real purpose is to flip open the QR on a climb, or bleed off a few MPH ahead of a tight corner on a descent.

I’m not sure how many pivots the new DA brake has, but I think you’re missing one critical thing: I have read that this new brake has an additional cam-based ‘force multiplier’ design (similar to the new SRAM Red brake caliper). So this might make the discussion of the no. of actual pivots kind of moot, and it also makes the DA brake quite different than anything made by Paul.

Didn’t count ‘em, but pretty sure the EE brakes got more pivots than any other brake.

http://bikehugger.com/post/view/bike-bedazzling-ee-brakes

@Byron

the eebrake is a linkage-type caliper (the arms supporting the pads are actuated by a linkage system operating in compression rather than the cable tension acting directly) and as such it shares more in common with the old (and much revered despite its deplorable performance) Campagnolo Delta brakes.  as such, comparing pivots isn’t really useful since the majority of the structure consists of linkages that work on the two primary pivots.  but if you want to compare linkages, the delta brake has more.

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