Protective rock guard coating for bike?

Hey all,

Anyone use rock guard or similar protective paint on a bash guard or crank arms? Both are getting pretty beat up from smacking the granite.

I like this idea:
http://www.raceface.com/guards/bike-protection/crank-boots/#.Uhf6FD-rt68

I wish I had known about those a few months ago. Mine are beat up enough now that there’s not much point.

I have a pair of the crank boots, they’re great. Unfortunately I beat my cranks up a bit before getting them but now they won’t get any worse.