Only bought these to coat the steel rims with something. ). This is the second time I've fitted 16" steel wheels (and appropriately sized tires) to a car that is fitted with 17" aluminum alloy rims to reduce potholing, the tooth decay, a bad ride and cause constant air leaks. The ABS plastic covers and metal retaining strap fit, and the covers stay on the car if the person installing them is careful and takes their time. In both cases I had to insert a metal ring in grooves that make assembly difficult. rim, but keeps it on the rim after assembly. My guess is that whoever has dropped them may not have been wearing them "tight". Installing the covers to keep them in place requires care. I've found that it's best to move the car so the valve is at the bottom, closest to the ground. Tape "on" the rim and insert the plastic fingers inside. With two fingers left (at the top of the rim), hold the bottom half and press down on your fingers until they start to go into the rim itself. The point where they close can suddenly "snap" into the rim as the plastic fingers pass the ridge on the rim. Much luck.