Where you live and how cold it gets can be factors of tire slip; cold makes metal contract. If your area uses corrosive salt/chemicals on the road they can start corroding the aluminum wheel around the bead area causing slow leaks too.
Aluminum wheels are nice for less rotating mass and all that, but for rock beating I'd vote steelies all day long. There's also bead sealant to help prevent corrosion and to help keep the bead seated; the stuff we used was like really thick black glue and we got it from Meyer's Tire Supply.
>>Dan
