they only have the inner plane. it is not centralized to the caliper, and can not be, as the caliper changes its center as the pads wear.

it happens on OE, and even more so with these. why would GM make theirs wider? lack of research to find out they could save $10 bucks on each of over 1 million vehicles?

you can actually see it happening first hand. this is not disputable.

the bracket keeps the caliper in a semi fixed position... not the rotor. that's just common sense. on a floating caliper, there is twist. i'm not saying the bracket twists. fixed calipers use a similar bracket, but they are in a fixed position, and cannot move. floating and sliding calipers move... a sliding caliper has a bracket almost all the way across, with a spring of some sort, depending on design, and there is very little twist. a floating caliper does not rely on its slide pins, or (duh) the rotor to keep it from moving. it relys soley on the bracket. the thinner, and less centralized the 'slap' surface is, the more it acts like a fulcrum, inducing twist. the lever action changes as the pads wear, and the caliper slides inward. there is not much, but there is some, except when the surface is dead center to the caliper.

i'm not saying this is a bad product. it is not as good as OE, and is not for those who abuse their brakes (most people do), and are concerened with optimum performance. they will work fine, but depending on how you use your brakes, you may experience uneven wear, premature wear, and you will want to replace the guide pins with every pad swap (which isn't a bad idea with OE parts either).

"slap surface' is my own defenition of the surface the caliper hits when it is thrown forward or backwards by the brakes applying. it really is vey slight. the twist i speak of is nearly negligable. i would still go with OE.