slaw

I recently bought a set of v-brakes to upgrade from cantilevers on my '86 Specialized Expedition. After running into some installation issues and reading online, it looks like like the pivots (braze-ons/brake posts) are too narrow. The brake arms have a good 4-5 inches between the tops and the springs do not engage to open the brakes. My current solutions are:

• Get a frame-builder to cut and re-weld the pivots
  
• Buy a new fork
  
• Hardware solution. It looks like there are brake post extenders for moving v-brakes higher on the frame. I have yet to find any that move the brake further out.
  

Does anyone have other potential fixes? If not, what is the best course of action from the above list?

(would post pictures, but I don't have enough posts. Sorry!)

mack_turtle

this sounds like you need to adjust the spring tension on the brakes so they engage the arms. the brake pivots are 99% certainly in the right place. you just need to adjust the springs for tension.

post a link to photos of the brake and the frame. if you can't upload photos, you can still find links to photos to share. what specific brake model is this?

ClydeClydeson

V brakes come with two sizes of washers... actually each arm has two sets of concave/convex washers of different thicknesses. The convex washers always go against the brake arm to form a ball around which the concave washers can rotate to adjust the pads. Make sure you have moved the thin set of washers to the inside and the thicker set to the outside to give the brakes the best chance at fitting on your older bike

Russ Roth

Depending on the fork there are three holes at each post that the spring goes in, some forks only have one hole but typically only suspension forks. Make sure the brake spring is going through the middle hole, I've never seen a use for the bottom hole but using it would create the problem you're having of the spring not engaging the caliper. The top hole is for worn springs and will create too much spring tension though if you're in the middle hole and having this problem you can use that top hole to help solve it. As Mack_Turtle mentioned, if the spring is properly positioned in the hole, you can use the adjustment screw to add tension to the springs and help them move the caliper.

dedhed

Older bikes often have the cantilever brake bosses narrower spaced than "modern" bikes and adding V brakes can be an issue.

https://www.bikeforums.net/bicycle-m...ring-fork.html

https://www.bikeforums.net/classic-v...rrow-fork.html

wesmamyke

I'd put the canti brakes back on. It's always the easiest solution for an older frame with narrow spaced pivots. Get some good cables/housing, and new brake pads, bonus points for swissstop pads or something else nice.

Even switching to newer canti brakes can be an issue for frames of that era.

mack_turtle

second this. the spacing of the posts and width of the rim will determine how to space the pads. the arms of the brakes should be close to parallel when the pads contact the rim. if they are canted out super wide or pinched in, the spacing on the pads is incorrect. https://www.parktool.com/blog/repair...icle-section-3

dedhed

this is what the problem most likely is. OP hasn't given us a stud mount distance. Too narrow and V brakes aren't going to work period.
https://velo-orange.blogspot.com/201...izing-psa.html

https://www.bikeforums.net/classic-v...part-help.html