Bicycle Mechanics - Brakes Losing Strength, front brake stutters when applied. Need advice

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Monument Man
05-04-05, 08:26 AM
Hi,

I'm relatively new to the world of taking care of my bike. I'm using it around 150 miles per week and that total is going to continue to increase as the weather gets nicer. Anyway as new problems arise I try to deal with them on a case by case basis, while maintaining good basic maintenance/cleaning/inflation for each ride.

My problem is my brakes. They seem to be less grippy than before, especially in the front which will shimmy shimmy shimmy when applied. It kind of feels like anti-lock brakes in a car.

I have Avid Shorty 4 cantilever brakes made for my cyclocross with Sora components. I sport nobby tires with 700-32 size and Bontrager rims.

I figure there's a few options I should consider:
* clean rims (although I try to keep the bike pretty clean). Is there any special solution I should use to do this?
* new brake pads? (they seem to be OK but maybe they're getting worn out and I have to adjust my brakes to move the pads closer?)
* tighten up the brake cable so it's more responsive?

Any tips would be appreciated.
THANKX


powers2b
05-04-05, 08:32 AM
Clean the pads with sandpaper
Adjust the cable
Adjust pads for 'toe-in' to stop vibration
Lube cables and caliper pivot point

Enjoy

Monument Man
05-04-05, 08:38 AM
Thanks for such a prompt response. After I clean the pads and replace them so there is sufficient toe-in, how do I assure that I'm "toeing-in" the proper amount? Is there a science to toe in or do I basically just angle the pads a bit so that the top hits the rims first?


StarFangledNut
05-04-05, 08:52 AM
Monument, when you toe in the pad, the leading edge of the pad (as in the part closest to the front of the bike), and not the top, should be what is touching the rim first when you brake. As far as how much you should toe it in, there is no general rule, although people have lots of tricks to doing it. One suggestion would be to slide a credit card or something of that width behind the tail end of the pad with the leading edge toed-in to touch in the rim and then tighten.

powers2b
05-04-05, 08:54 AM
The front of the pad (not the top) should hit first.
When the front of the pad is touching the frame there should be enough clearance at the back of the pad to fit a couple business cards.

Enjoy

moxfyre
05-04-05, 09:00 AM
My problem is my brakes. They seem to be less grippy than before, especially in the front which will shimmy shimmy shimmy when applied. It kind of feels like anti-lock brakes in a car.

If it feels like the whole front of the bike shakes when you brake, you may have a loose headset. Grab the front wheel with one hand and the handlebar with the other. Try to shake them forwards and backward, if you feel a knocking back and forth then your headset is loose.

This may not be a problem, but if it is then working on the brakes directly won't help much!

Monument Man
05-04-05, 09:17 AM
Great, I always thought toe-in was the other way around. This forum is a great learning experience. I'm sure tomorrow I'll be dealing with a new question about my derailer, etc but I take them as they come.

Pretty sure it's not a loose headset but I will check.

Monument Man
05-06-05, 09:48 PM
By the way my cyclocross has Avid Shorty 4 brakes and the guy in the shop basically told me that they suck. I'm replacing the pads. He said that the Shimano brakes they had in the shop were even worse. Hopefully the new pads will get the brakes back to where they were at first.

A car pulled in front of me yesterday and my brakes didn't stop me at all and I took a big spill. Totally fine but definintely time to deal with this issue!

Avalanche325
05-06-05, 10:33 PM
You can clean the rims with a scotchbrite pad and alcohol. Sandpaper is good for the pads. Just knock the shine off of them.