cantilever brake play

[erikv]

I've attempted to put a pair of Tektro Oryx canti brakes on a '06 Giant
TCX Cyclocross bike.

There's a lot of play in them, and I think it's due to the brake not
being able to clear the part of the canti post with two flat wrench
faces. So the brakes don't sit flush against the frame or fork - they
sit against that bulge with the two wrench faces.

I've tried a washer but I don't think I'll be able to use one wide
enough to eliminate all of the play, because it would push the brake
too far away from the hole that holds the spring.

I've tried one different canti boss, same effect. I could try another
brakeset. Before I do, does anyone have any wisdom to pass on from a
similar experience?

Thanks,
Erik

 

[Nate Knutson]

erikv wrote:
> I've attempted to put a pair of Tektro Oryx canti brakes on a '06 Giant
> TCX Cyclocross bike.
>
> There's a lot of play in them, and I think it's due to the brake not
> being able to clear the part of the canti post with two flat wrench
> faces. So the brakes don't sit flush against the frame or fork - they
> sit against that bulge with the two wrench faces.
>
> I've tried a washer but I don't think I'll be able to use one wide
> enough to eliminate all of the play, because it would push the brake
> too far away from the hole that holds the spring.
>
> I've tried one different canti boss, same effect. I could try another
> brakeset. Before I do, does anyone have any wisdom to pass on from a
> similar experience?
>
> Thanks,
> Erik

I heard from a friend who works in a shop that deals with many bikes
with Oryxes that there was a "bad batch"-type issue with some Oryx
brakes where a bunch had excess play simply due to what sounded like
one part or the other of the integral pivot being too long or too
short, resulting in excess play (and unstoppable squeal issues). He
told me this only affected OEM Oryxes - which means it's most likely
this defect would be found on brakes that were OEM, but OEM stuff ends
up getting sold aftermarket all the time so that doesn't really matter.
I think this is probably what's going on for you, but can't really be
sure. The design of the brake would seem to dictate that if in your
case, if you tightened the mounting bolt and the back of the brake made
positive contact with anything at all and the play was there, it would
be the same regardless of whether the canti posts had wrench flats that
could interfere (and that's a weird issue to have in any case,
especially considering how mass-market both the brakes and the
frame/fork in question are). I'd try mounting the brake on a canti post
that doesn't even have wrench flats. If it still has the play, it's
almost certainly one of the defective brakes.

Also, I just checked how much play some Oryxes on a bike at hand have,
and it's pretty normal - without measuring, about 1-2mm of play at the
end of the brake arm when it's grabbed and rocked back and fourth
gently.

 

[erikv]

Thanks for that info. Very interesting.

I actually got each brake from a different source, and they both behave
the same way. While they could both very well be from that bad batch,
I would think it's less likely.

-Erik