What's the secret to keeping your brake calipers centered on the wheel?

Every couple of weeks I find that my Shimano Ultegra brakes are skewed to one side, with one pad or the other conspicuously closer to the rim. (Sometimes even rubbing.) I've just been grabbing the pads and muscling them back into position, but this seems inelegant, and (obviously) is not a lasting solution. Do I just need to tighten the bolt that holds the brakes to the frame, or is there something else I'm overlooking? Thanks.

This seems to be a common issue. If these are dual pivot types, there is a setscrew on the brake bridge. Use this to center the brake. However, make sure the mounting bolt is tight, or it will move as you note. See also
http://www.parktool.com/repair/readhowto.asp?id=20

The mounting nut might be too long. If the nut bottoms out on the bolt, the brake won't be tight. If the brake is tight, it shouldn't move.

Try removing the brake and putting small washer between the brake and the fork.

The mounting nut might be too long. If the nut bottoms out on the bolt, the brake won't be tight. If the brake is tight, it shouldn't move.

Try removing the brake and putting small washer between the brake and the fork.

If putting a washer in place - I find it best to use a Lock washer.

Another point that is often overlooked is cable housing that is too short. When the brake lever is activated to full power and the brake shoes are gripping the rim, make sure that there is enough length in your housing so as not to pull the brakes out of center. Good luck!

If these are dual pivot types


Oops, yes indeed, these are Dual Pivot. (I must be showing my age: When I learned about brakes there were only side-pull or center-pull!)

Thanks for all the suggestions.