Bicycle Mechanics - Uneven/Bumpy Braking Surface

Hi, i recently bought some used wheels(500 miles), the rims are alex rims at450 i believe. After a bit of riding iv noticed that when im braking at high speeds the brakes make a terrible scraping noise. Im not sure the two are related but on the braking surface there are some small bumps of metal all over the braking surface, i took a little sand paper and tried it on a small area and it appeared to reduce the problem would it be wise to sand down the whole rims?

Could anyone shed any light on my problem?

I tried my best to capture the bumps but this is the best i could do, http://img195.imageshack.us/img195/5004/1001964e.jpg they are much more prenounced than how they look.

Sanding should help. Softer brake pads may also help. I like the KoolStop salmon colored pads.

Al

Thats interesting, my brake pads are like bricks. Thanks for the advice

I have the stock shimano pads on my cantis at the moment and the stopping power is terrible this gives me even more reason to change my pads.

Thats interesting, my brake pads are like bricks. Thanks for the advice

I have the stock shimano pads on my cantis at the moment and the stopping power is terrible this gives me even more reason to change my pads.

With softer pads your rims will last longer. Shimano pads tend to be too hard, I always replace them.
Also be sure your wheels are true.

Also be sure your wheels are true.

:thumb: +2

My wheels are mostly true, maybe a couple of mm here and there. Would this make a lot of difference?I found on my mtb with v brakes that untrue wheels made no difference and these were really out of true.

My wheels are mostly true, maybe a couple of mm here and there. Would this make a lot of difference?I found on my mtb with v brakes that untrue wheels made no difference and these were really out of true.

2 mm would be huge. 1 mm is a lot.

Maybe im exaggerating