Avid Shorty Ultimate brakes - why they are not

[silentbutdeadly]

My cross bike is equipped with Avid Shorty Ultimate canti brakes. They look much like this...


They came as part of a Rival groupset deal I negotiated with my LBS but I wanted them anyway because they'd been reviewed well in the past. Fitting and adjusting was a doddle. Most importantly, performance in the twelve months since has been excellent. They do what brakes should do.

BUT

They have a major flaw. The red alloy widgets that hold either end of the straddle wires are retained within the black frame by O-rings. Nominal size appears to be 9mm ID by 1mm thick. It's a really simple solution - lightweight & effective. However, the O-rings perish at the speed of light. If they fail only the straddle wire keeps the widget in place. And if you have the wheel out then the straddle wire is disconnected on one side and your widget on that side is free to roam. if you lose it then your $120 investment is toast...

Fortunately I haven't lost mine but after twelve months...every O ring is rooted. Some have lasted less than half this time...

There has to be a better solution. I've thought about using circlips but I suspect there could be a metal on metal issue...

[Jesmol]

Try to get hold of Viton O rings in the same size, Much much better in all respects.

[RonK]

They have a major flaw. The red alloy widgets that hold either end of the straddle wires are retained within the black frame by O-rings. Nominal size appears to be 9mm ID by 1mm thick. It's a really simple solution - lightweight & effective. However, the O-rings perish at the speed of light. If they fail only the straddle wire keeps the widget in place. And if you have the wheel out then the straddle wire is disconnected on one side and your widget on that side is free to roam. if you lose it then your $120 investment is toast...

I have not noticed this with my Ultimates - time a close inspection...

[silentbutdeadly]

Try to get hold of Viton O rings in the same size, Much much better in all respects.

I assumed they would be Viton or neoprene rather than plain old nitrile rubber. It'd be even better if I could get EPDM or flurosilicone O-rings but I'll have to do more hunting for that.

Oh and what a surprise...SRAM only supply the complete barrel adjuster & cable anchors...not the individual O-rings.

[silentbutdeadly]

I can vouch for the fact that the replacement O-rings are indeed 9mm ID by 1mm section. At a cost of around $2 for the set...it won't break the bank. Definitely worth stocking up on some spares though as the larger temporary replacements bugger up the brake performance by not allowing freedom of movement of the blocks.