My road bike has Shimano dual-pivot caliper brakes like these.
Whenever I remove or refit the mudguards, or even sometimes just getting the wheel out, they seem to go slightly off-centre, by which I mean rotated around the mounting.
The effect of this is that, when the brakes are applied one pad contacts the rim before the other. Looking carefully the wheel also moves a little to the left or right as one pad pushes it to the side.
I try to rotate the brakes so that both pads contact the rim at the same time to minimise this movement, but as the act of tightening the mounting screw also rotates the brakes slightly, this is tricky.
So the question is - does it matter much if one pad makes contact slightly before the other? What are the likely effects of it doing so?