Cantilever Brakes - hard to squeeze - kids bike

[DarthPaul]

We just bought a bike for our 9 year old at a garage sale, and he is not able to squeeze the back brakes hard enough to make a quick stop. It is hard for me as well. Safety is my main concern, so i haven't let him ride it.

What should be the first think that i check? Could it be the brake cable that is causing the problem? There is a bit of a kink in the cable near the back brake, but i am not sure that that would cause it to be hard to squeeze.

I have lubricated the joints and areas that move to see if that helps, but didn't.

Thanks in advance for your help.

Darth Paul

[Joe_W]

Kinks in the cable are bad. Worn cables / housing is bad, wrong cable routing is also bad, when the yoke cable is set up the wrong way it is also not good. Lubricating (with grease!) the joints is a good idea, but the brake needs to be disassembled for that [ which is easy: unhook the cable, unscrew the bolt, carefully slide off the brake arm from the brake boss (careful cause you want to make note which holes the spring was in). Clean break boss (remove rust with very fine sand paper), apply some grease, reassemble (taking care to put the spring in the same hole as it was in before) ]. (sorry for nesting brackets...(no, really!) )
Breaking performance will also benefit from good brake pads. How old is the bike? Have the pads been replaced (ever)?

Check http://www.sheldonbrown.com/caliper-brakes.html for an overview of how to route the cable, set the mechanical advantage etc.

[DaveC]

I had an experience today that i think may explain what's going on with your bike.

i just bought a used Schwinn 20" bike for my daughter at a garage sale and when I got it into the shop to give it a once over before i let her ride it I saw that it is built with v-brake (linear pull) levers and BMX style caliper brakes. The levers pull more cable at a lower leverage than the brakes require resulting in them being useless. The bike has got a coaster brake so I wouldn't call it unsafe, but really this is inexcusable. There's no way they're not the original levers, they're painted to match.