Gritty or slimy cables can be a problem. Clean or replace?

Don't ride muddy trails. But for dirt-road slop, there's how to keep mud out.

Replacing a brake or derailleur cable.

It's best to simply replace a bent derailleur hanger. But straightening it can get you a ride or two while you wait for a new part.

Pulleys can wear out. More often, they malfunction because you didn't clean them. Ever.

How to improve shifting up front.

If your bike has more than one ring up front...

Tuning the rear shifting is science, not art.

Replacing a rear derailleur.