Rims and grit abrading sidewalls
 

I've heard several people mention this problem, including Sheldon Brown. When narrow rims are used with fat tires, and the rides are long and gritty (as on long tours over bad roads) the problem tends to be worse.

I'm wondering about possible solutions. Somewhere I read about sidewall protectors that can be installed between the rims and the tires, but I'm not sure where they are sold.

Also, there may be other solutions (aside from wider rims and narrower tires). Does anyone know how this problem can be prevented or slowed down?

Can you set your brake pads farther out from the rim? more clearance == less rubbing. and ideally, no rubbing :)

Disc brakes.

Disk brakes will fix that. If its too much to do for this minor issue, I would simply clean the wheels more often.

Cleaning can be really easy. Squirt some dish soap on your rims and go for a ride in the rain... somewhere flat.

Hehe...

Reminded me of one time when I helped my brother overhaul his moped. We took the entire engine apart and put it back together, and that was fine. We also took apart the front drum brake, cleaned and degreased it. Sadly, in a momentary lapse of reason, we decided to oil it...
That front brake never worked again. :D

I use a file card to clean the grit out of the pads. You have to take the pads off to do it, though.