What are the main differences between stock steel rims and aftermarket alloys? I know the big one is looks, but what about structural differences? Do the stock steel ones flex more than the alloy? Any help would be greatly appreciated.

 

weight. im not too sure about strenght.

 

One reason that people get aftermarket wheels is size. They either want a bigger diameter wheel, or a wider wheel.

They get the bigger sized wheel so that it could accomodate a bigger (and probably most importantly a wider) tire. Bigger tire means more rubber on the road. Also most now get wheels because they are lighter. Less weight = better accelration.

But right now most folks are putting on their steelies for the winter. They don't want to ruin their nice, lightweight wheels plus some have snow tires on their steelies.