unbelievably

This is a double post from the road bike threads.

I have 105 brakes and pads and I ride on Mavic Open Pro CD rims.
Both are new.
When decending, they squeal and shudder.
I don't like it...

Is there something that I'm missing???

Stacey

Have you oiled them? I've found that lack of lubrication is the most common reason for a majority of bike squeaks. j/k


First thing I'd check is pad toe-in. I use a rubber band on the end of the pad to gauge my toe.

When viewed from above the pads shouls be toed like this: /||\ (exagerated of course)

TallRider

105 pads don't typically allow adjustment of toe-in.

What brake calipers do you have, and how well are they adjusted? This can contribute to shuddering, esp. if the arms are slightly loose. So there may be something to do with oiling and adjustment, although not the oiling of the pads of course

One possibility - are the rims new? Are the pads new?
Hard-anodizing isn't a good thing for rims. Yes, it makes them harder. Yes, this makes them more resistant to wear from the brake pads. It also diminishes braking performance because pads don't grip the hard-anodized surface as well. Moreover, the hard surface can form cracks that can propagate into the aluminum itself, making hard-anodized rims more likely to fail by cracking at the eyelets.

Rims with hard-anodized sidewalls, like the Open Pro CD, can build up rubber from the brake pads on them and become "grabby" on the pads.
Over time, hard-anodized rims get "worn-in" by wearing down from the brake pads. The hard-anodized surface gets worn away, at least partially, and brake gunk is less likely to build up on this worn-down surface. Here's a couple of pictures of an MA40 rim (hard-anodized version of the MA2), showing the worn-down sidewall after 7,000 miles.



So if you've got rubber gunk built up in spots on the sidewall, clean it off with mineral spirits and a rag, and the brakes should become less grabby. If you want to accelerate the wearing-down of the hard-anodized sidewall, you can put on old brake pads and stick pieces of sand in them (or just ride in the rain, when grit gets into the brake pads and makes them wear down the rim more quickly).

well biked

Brake squeal is a tough one to solve sometimes. Regardless, I'd switch the pads out to some Kool Stops with the salmon colored compound and see what happens. They're definitely better pads than the Shimano pads, which are IMHO the worst pads made for noisiness and being hard on your rims, both very undesirable traits in a brake pad if you ask me-

San Rensho 

Tim gave good advice about checking caliper arms for looseness. Also try sanding the rims with 80-100 grit paper then clean with brake cleaner. File the pads with a mill bastard file to get to fresh pad material.

turtle77

In the past, I have gently bent caliper arms slightly inward to get a toe-in from 105s. Brakes worked flawlessly, as before, but with no squeak.

the royal 'we'

You can always adjust toe-in. Sometimes you can get an elliptical washer to go between the pad and the brake arm, but if you have limited room/are lazy, get an adjustable wrench, put it on the brake arm right above the pad (or remove the pad), and gently twist the front inward. Not much, maybe 1 degree or so. Kinda ghetto, but it works.