Project KONA Part 5 (rear brake boss woes)

[messiah]

I had a similar issue with my Lloyd - by jigging the spacers round I could eventually get the V's set up okay. You've got the right idea with the spacers - I nipped into my LBS and was given a few spares from binned brake blocks to help, but I was never 100% happy with the result so I went for Canti's.
I also looked into which brake blocks to use as some of them are thicker and have longer bolts which would/could help.

If you can find a V-brake which uses post mount pads then that may work better - although they are a nightmare to set up. I looked at doing that on the lloyd but I needed the brake to come in from the RHS which severely limited my brake options :roll:

 

[tiboltrider]

I had the same issue when trying to fit XTR V brakes to my Rocky Mountain Ti Bolt. Try wider rims if you want to keep the brakes or change the brakes. Cheaper Vs fitted with no problems at all, but I've gone for canti's now. HS33s will fit ok.

 

[Anthony]

The brake bosses have definitely been moved, they were originally mounted on brackets on the inside of the stays.

It doesn't look too bad a problem though. You will need to replace the existing spacers so that you have a cup and cone on each side of the brake arm, otherwise you won't be able to align the pads correctly. But you just need to fit sufficient plain washers to recreate the width you have in the photo. Hopefully you will still have enough thread to secure it and the brake should work ok, although clearly the wider the rim you fit the better (but then that's always the case anyway).

We old-fashioned British have an old adage (or at least those of us old enough to remember it do) 'time spent on reconnaissance is seldom wasted'.

 

[legrandefromage]

wider rims or STX-RC V brakes or sexy cantis

its an old arguement but cantis set up correctly are just as good as v-brakes. People just dont take the time to set them up right.

 

[one-eyed_jim]

The problem with cantis or plain (non-parallel-push) v-brakes on this bike is that there's going to be hellish brake dive.

If you draw a circle centred on the brake boss that passes through the rim face, the tangent at the point of contact with the rim tells you the direction of motion of the pads when the brakes are applied. With the bosses set as wide as these are, the pads are going to be diving under the rims after just a little wear. The track ends (not angled to keep the rim aligned to the brake) compound the problem, and will make adjustment a nightmare.

Maguras at least avoid the dive problem.

 

[messiah]

My eventual solution for the Lloyd

The rear bosses are a whopping 95mm apart - by setting up the Canti's near the end of the posts and with the straddle low slung these are as powerfull as the Avid Ultimate Black Ops V's they replaced...

Here was another thread on the subject

http://www.retrobike.co.uk/forum/viewto ... w=previous

 

[RockiMtn]

first time i installed my first set of used set of shimano parallel v-brakes, one of the pads did not properly contact the rim. no matter how much jigging i did with the proper amount of spacers installed on each side of the pad posts, it would not line up properly.

finally i figured out why. it may be possible that the return spring pin section at the base of the brake arm was aligned properly to the brake arm itself. that pivot/pin part of the brake with the pin had come off the base of the brake arm and i had put it back on misaligned. after a bit of trial and error, i matched it back on properly and i got the pad to contact the rim properly.

i'm not sure if this is the case with you're situation, but i would maybe measure the two brake posts and see if it's the correct distance. if it is then i'd suggest pull off the pivot/pin part of the brake and try to re-align it, as in my case.

not sure this makes any sense, as it's hard to explain, and i'm not sure of the proper names of the parts on the v-brake.

 

[DocBraunson]

thanks yall,

i think the way it is set-up now is going to work although not ideal, and definitely not to shimano spec. sounds like new rims, or set up for Cantis. ON a lighter note the Front brake works awesome maybe i will just have to get really good at stoppies.

So does this frame look like it was set-up to be a trials bike or what? someone went through a bit of trouble to modify the hell out of the thing.