wilf1234

Hi. I've built hundreds of bikes, but I must be getting old......

All winter I've been struggling with a
Pair of bog stabdard retro stx v brakes, I just can't get them set up properly. Even with the brake arms splayed out as wide as possible, The pads are just too close to the braking surface on the rim.

I'm using standard pads and standard rims (mavic 519), and have had the frame set up previously with lower quality brakes, and the stax brakes used successfully on another bike.

​​​​​​(I've changed pads and rim around and still no joy)

Am I missing something obvious?

Cheers
​​

Rolla

Re-configure the washers.

wilf1234

Thanks, but I've already got them configured with just the 3mm washer on the wheel side...
It's really really strange! I must be doing something properly stupiy!

grizzly59

Measure the frame / fork spacing of the studs vs another bike that the brakes work on. You may have an oddball frame that only takes a certain series of brake. If you’ve got that experience I’m guessing it’s not you.

dedhed

https://velo-orange.blogspot.com/201...5%20mm%20wide.

wilf1234

Thanks guys...

Yep I'd already measured the geometry, albeit pretty roughly, and it all looked good. I've changed pads and wheel sets and still no joy.

I think I'm going to have to get a bit more 3d and a bit more accurate with the geometry. BUt even so, it's just really wierd that other similar era v brakes work fine on this frame...

Cheers

bboy314

I’ve worked on older touring bikes whose brake studs were spaced very close together and had this problem, seemed to really be made to work best with narrower rims. Also Kool Stop slim line pads can help this with V brakes but I don’t know if they make them with an unthreaded post.

wilf1234

Yep, the post spacing is definitely not the problem (although I suppose one post could be bent, although they look fine).

wilf1234

Yep, the post spacing is definitely not the problem (although I suppose one post could be bent, although they look fine).

tFUnK

I assume you already tried backing out all the centering screws on each caliper before installing onto the studs?

dedhed

I suppose you could use extenders run sideways to move the arm outward although it may be an issue of the spring hole orientation.

https://www.amazon.com/BOX-COMPONENT.../dp/B0781XX9Z9

AeroGut

some photos would be helpful here. If you did do something incorrectly in the setup, it's unlikely anyone is going to guess what it was without seeing the setup.

Andrew R Stewart 

So how far apart are the bosses? It's typical for the boss to boss dimension to be 50-55ish mm wider apart then the rim is wide. Like bboy314 I've worked on bikes with vastly closer together bosses and struggled with getting the best from a poor arrangement.

Possible solutions are thinner pads, grinding down pads, different brakes, different rims. If the bosses are mounted too far up the stay/blade the pads begin to arc to the rim at bad angles and reduce the amount of pad/rim gap. I've seen bikes made for 630 ISO rims gain this problem when 622 ISO rims were installed. Andy

wesmamyke

I need to see some pictures for sure. I actually use these brakes specifically because they have a crazy range of adjustment. Only V-brake that will work with 40mm wide rims on a normal mountain bike. The version I have uses smooth post canti pads though, not sure if they always used canti pads.