got a new frame and the rear brake bosses seem to be.. well odd. the v-brakes (avid) i've got won't fit very well, tried some lx ones and they don't either.

do v brake bosses come in different sizes? i wouldn't have thought not, but i'm fed up fettling and getting nowhere.

anyone got any ideas???

Magura mount?

The actual boss doesnt, but the fixing to the frame either comes in 8mm (usually fork) or 10mm (usually frame) thread diameters/

Dont Maguras run on normal bosses Kato?

its not the thread and they're not magura. hte v-brake just don't slide down the stud enough. and the spring thing is only just sitting in the hole in the frame.

could the studs be too long?

or too fat?? which is what i think

Just go brakeless! Its the way forwards.

lol i never go that fast anyways, but i need a rear lever to grip just in case i do. ;-)

any other ideas matt?

What are V brakes?

Sorry, I seem to remember having the same problem in the dim and distant past. It was a simple answer, but one which escapes me at the moment.

If the bolts are too long they will bottom out on the thread before the brakes are actually tight. Doesn't really sound like your problem though. Pretty sure they do tend to come in slightly different lengths, may be worth going to the LBS, try and get another pair.

I hit the same problem yesterday.

I tried to transfer the rear V brake from a Trek 8500 frame to a Specialized stumpjumper.

The brake was an Avid and fitted fine on the trek frame but it seems like the boss is too long on the stumpjumper. The old brakes on the stumpjumper were also avid but they fitted fine.

I don't get it!

so the studs are longer?
have they shrunk over time? technology eh!!!

It seems like the older studs are a bit longer. I'm taking my bike down to the shop at lunchtime to see what they say, so i'll let u know what i find out.

the guy said that i can remove the studs and replace them with the ones off the other bike. he also said they should all be the same size.

i'm gonna try and swap them tonight

I found out what the problem was. The bosses can be unscrewed from the frame, and when i compared the bosses i'd taken off the two frames they were identical.

The hole on the frame is recessed and the boss can only be screwed in so far. One frame had a slightly deeper recess and the other didn't, causing the brake's tension spring pin to not fit correctly into it's little hole.

I couldn't get the brake i wanted to use to fit, so ended up fitting a brake off a different bike.