105 Front brake calipers move out of line

by chrismday   April 1, 2014  

I'm hoping someone may be able to shed light on what is happening here.

I carefully center the calipers so that each pad is equidistant from the rim, go for a ride and they're off center again. Only happens to the front brake, not the rear. Wheels are pretty solid Mavic Ksyrium Elites and the rims are true.

At first I thought it was the centering adjustment screw turning because the pull forces go through the screw, but I've loctite'd it and the caliper still goes out of line. There don't seem to be any obvious forces that would tend to push it out of line. Bit puzzled really.

Any ideas?

8 user comments

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Have you tried tightening the bolt that holds the brake to the forks?

posted by Yorkshie Whippet [332 posts]
1st April 2014 - 12:56

1 Like

Loosen the bolt that holds the caliper to the fork. Fully compress the brake lever and hold it there. Tighten the bolt. Your brakes should now be centred and, unless something else is loose, should remain centred.

posted by Peowpeowpeowlasers [122 posts]
1st April 2014 - 13:44

2 Likes

has it got one of those washers with the "teeth" on between the forks and caliper? (something a bit like this: http://bikeshopliquidators.com/images/product/large/BKPT1213.jpg.)

posted by chris75018 [100 posts]
1st April 2014 - 13:45

2 Likes

It might have something to do with each arm of the calliper moving in arcs with different radii. As your pads wear down this can become more pronounced.

I had a problem a few weeks back where the pad (only a 1/3 worn down) was missing my rim on one side and sliced through the sidewall of my tire.

posted by Scoob_84 [229 posts]
1st April 2014 - 14:08

1 Like

It's just possible you have the front wheel not quite fully in the fork end straight. Undo the quick release, make sure the hub is seated properly, do it back up.

posted by MKultra [284 posts]
1st April 2014 - 14:15

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Thanks for all your comments.

Everything is correctly set up to specified torques (carbon forks), wheels seated properly etc.

Yes, it has the toothed washer; are you just checking Chris75018, or is there a problem that you know of?

The differential wear due to the different arm arcs is a good point, but this is happening in too short a time; it's not due to pad wear.

posted by chrismday [49 posts]
1st April 2014 - 16:35

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A suggestion: if one of the pivot arms is experiencing greater friction than the other it will tend to drag the caliper as a whole out of line with repeated cycles of use. I'd suggest checking the operation of the caliper off the bike and if it's there's noticeably more friction on one arm than the other strip it down, lubricate it and see if that does the trick.

Or use this as an excuse to upgrade of course!

posted by Nixster [105 posts]
1st April 2014 - 16:56

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I agree with the tip to loosen the calliper from the fork, but make sure its only slightly so that you don't change the fore/aft alignment, apply the brake and tighten up, I would also set the centring screw to about 1/2 way to make sure you still have enough fine adjustment.

I would also have a look at the cable inner and outer condition and lengths, if there is any friction there you may find that the spring on the calliper is forcing one side out/in further than the other as the spring energy needs to go somewhere. I have seen this more on older bikes where the outer is cut either to long or short, but to be honest I have never seen it on any of the high end Shimano kit

posted by jason.timothy.jones [303 posts]
3rd April 2014 - 7:54

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