Project KONA Part 5 (rear brake boss woes)

[DocBraunson]

got the frame:

1. Blasted
2. Identified
3. Powdercoated
4. rear re-spaced
5. ????? REAR BRAKE bosses are for Cantis only? too wide for Vees?

i went about fitting my br-950 xtr brakes and levers on the frame and ran into an issue. the rear bosses are too far apart! if i adjust the brakes just right they work as the tops of the brakes are almost touching and at rest they look totally dumb and almost touch the tire... is there a conversion. basically i need the bosses closer to the wheel like newer frames. can post pics if it helps.

help!!!!!

 

[RockiMtn]

i think you should post some pics, cuz that doesn't sound right. :? any frame i've come across that had canti's, the post easily accepted v's without any issues.

 

[DocBraunson]

so mind you this frame had been modified and i am not sure if this was changed too but looks like the bosses come directly out from triangle not off-centre towards the wheel like newer ones seem to be.

the spacing you see is with no adjusters on the outside of the brake pad. i moved both to the inside, between the pad and the brake. this set-up works but doesn't seem right... any tips are appreciated.

 

[RockiMtn]

:shock: uhmmm.... half of those spacers/washers go on the other side of the brake pad post!

 

[RockiMtn]

here, took a quick pic for you on my setup, to understand what i mean. i think you might have one extra domed washer from what i can tell from your pics.

the large and small washers can be interchanged on each end depending if you want the brake pads/arm closer or farther from the rim.

the two domed washers stay in place on each side of the brake post mount.

 

[RockiMtn]

better yet, here's your pic with where you should move things

 

[DocBraunson]

well see i had to put those spacers over there because i needed the pads closer to the wheel. otherwise the v-brakes will almost be touching each other when the pads are engaging the rim.

basically i need a way to get the pads closer without using extra washers. hence my thought that the brake bosses too were modified. any ideas?

 

[one-eyed_jim]

I think your brake bosses must have been repositioned at the same time the dropouts were changed. The bosses on my '94 Kilauea are 80mm apart centre-to-centre, and offset inward from the stays as is normal. It's possible the previous owner of your bike was using a super-wide rim and had the bosses moved to accommodate the extra width.

With a brand new paint job, I don't suppose you'll be keen to take a torch to the frame again. I think if it were mine I'd be considering Magura rim brakes with offset trials mounts reversed to push the cylinders in towards the rim. You could also think about a disk brake adapter, a wider rim, or (though I hesitate to suggest it here) a fixed hub - or even a geared hub with an integral drum brake.

 

[FluffyChicken]

If that is how it has to be, then work out how long the spacer you need is to get the correct distance as per shimano spec at the top. Go buy some Alu tubing and cut it to length, or maybe brake booster spacers or chainring spacers would work. Or anything similar.

As long as you can still screw the pad on then it shouldn't matter too much. Especially with the p-push brakes.

 

[Neil G]

Rim width definately coudl be the issue/difference in the boss spacing.

In other words if you want to keep the frame you may have to get wider rims!