Calcium will eat the rims out in about 12 years. My MF1655 is about to get its 3rd set of rims, if I can get my other 1655 out of the way. Six years is a little quick and makes me wonder about the quality of the steel.I've not heard of that happening, but I've often wondered about it. Just to make sure we are on the same page here, do you mean you had ballast (calcium) in the wheels and it ate holes in the rims? If that is what you mean, I've worried about that. I've been thinking of either going to tubes or putting beet juice in the wheels instead of calcium.