When I changed my tires there was rust on the inside of both rims. The front was much worse than the rear. The rust was wire brushed off and then I sprayed the inside of the rims with Amsoil Heavy Duty Metal Protector (my chain lube), which was originally developed as a undercoating. I made sure the area where the tire seats to the rim was clean and dry. Installed a new rubber rib, then tire and inner tube. Hopefully this will stop any further rusting. The next time I change tires will warrant a more detailed inspection.

Tom

Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety. Benjamin Franklin, US author, diplomat, inventor, physicist, politician, & printer (1706 - 1790)