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Old 01-16-13, 09:58 PM   #1
JPprivate
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Avid BB7 front brake problems

Hi I was wondering if somebody had some insight for my problem.
I recently bought a Surly Troll with mechanical Avid BB7 disk brakes (160mm rotors).
What I read, it looks like the brakes need to be worn in a little bit to develop their full power. The rear brakes work great, but the front brakes still haven't developed their full grip. (after about 300 miles of riding)
What could be the reason for that? Essentially the rear brakes give me currently more stopping power than the front brakes. I can't even get the front brakes to lock up. That can't be right, can it?

Thank you for any advice.
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Old 01-16-13, 10:02 PM   #2
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the break in, is a fairly slow speed application repeated many times , did you do that ?

Are you sure the pad clearances to the disc is right..
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Old 01-16-13, 10:10 PM   #3
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Originally Posted by fietsbob View Post
the break in, is a fairly slow speed application repeated many times , did you do that ?
Yes, I did this since I had it, for the rear breaks it took no time. But I do have the problem with the front brakes.
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Are you sure the pad clearances to the disc is right..
Not sure. The pad is touching the disks when I engage the brakes. What else should I look out for?

Thank you
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Old 01-16-13, 11:13 PM   #4
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Front brakes act differently from rear brakes. When you apply brakes the weight shifts forward lowering the traction of the rear wheel and increasing that of the front.

That's why auto brakes are proportioned with over 60% of the brake force applied to the front wheels. Even then cars are prone to rear wheel lockup.

Likewise on a bike, so locking the wheel is a poor way to judge whether brakes are efficient. Instead try to judge if you're getting sufficient and similar slowing through mid-range braking. Remember that rear stopping power is self limiting, but front can increase to the tipping point at which you see an endo.
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Old 01-16-13, 11:52 PM   #5
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I reccomend going back to your favorite bike shop , and have them show you how those brakes adjust,
1st person,
since the pad wear being a manual adjustment, requires your regular attention.
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Old 01-17-13, 08:37 AM   #6
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What else should I look out for?
Make sure that the rotor is true.

Even if the rotor is out of true by 1mm it will affect how the brake performs.



BB7 Installation & Setup Guide: http://cdn.sram.com/sites/default/fi...d7_English.pdf

* pads need to be broken in before they'll work properly
* if pads are contaminated they will work very poorly

Last edited by cobba; 01-17-13 at 06:12 PM.
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Old 01-17-13, 09:51 AM   #7
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First make sure nothing has contaminated the pads/rotors, simply pulling the pads lightly sanding them and cleaning the rotors with alcohol would be my first step. After that make sure everything is set up properly, it is surprising how many people do not get mechanical discs even close to properly adjusted. There is more to it than making sure the rotor is not rubbing and the cable is tight. You can check this out for advise on how to set it up right. http://www.crazyguyonabike.com/doc/?...c_id=11218&v=Y
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Old 01-17-13, 04:57 PM   #8
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Thank you for all the advice.
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