Armorall is crap, and should never be used on anything! On motorcycle and bicycle seats and tires it makes them slick and dangerous (as well as speeding degredation of the material, despite what they claim). On cars is speeds up the degredation of vinyl surfaces and tires.

'tire gloss' on the motorcycle tires is one of the classic ways that newbies embarass themselves in front of experienced motorcyclists.

I just hose off the tires now and again when they get dirty. If there is something yucky on them, or oil from my hub gets splattered on the rims, I hit them up with a little 409 and then hose off. Go for a quick ride to dry them off (knowing that your brakes won't be as good for a minute), and you're done!

peace,
sam