Hubcaps and Rims Okay, so this is something that's been bothering me a while. I know there's a fundamental difference between hubcaps and rims in the sense that a hubcap is placed over the rim of the wheel. So you have the rim inside which actually lines the wheel's inner circumference, and then you have a hubcap over it. Of course, hubcaps are used when your rims are not pretty. So there's that I understand (I may very well be wrong on this point). But what is there performance-wise? I guess without hubcaps, your car is lighter, but in terms of the wheel and all, how do hubcaps and rims affect the performance of your car?