Wheel offset

[manicmechanix]

I was wondering if anyone had the info on the exact wheel offset for an '89 oldsmodile Cutlass wheel and for a '97 Malibu wheel. I'm trying to determine if the two cars use the same offset or what. I can't find the exact offset dimension anywhere and the wheel doesn't seem to be marked with the offset. It's usually stamped "ET" follwed by the mm of offset, but the factory wheels don't seem to have an offset stamp.



I actually put the Olds wheels on the Malibu and I can't really tell if they might stick out more than originals or not. I've heard that all the GM FWD wheels had the same high offset of maybe 40mm, but I'm not sure about these two applications. The car seems to exhibit signs of the original negative scrub radius being positive due to a higher offset of the Olds wheels.

[LeftVentricle]

Usually GM's FWD wheels are between 35 and 40mm. A notable exception is Cadillacs from the late eightes/early nineties, which have a 55 offset. I tried putting some Grand Prix crosslaces on a '90 Deville and it rubbed like crazy, since the wheels were tucked in way too far. Damn shame too, the Lac looked pimpin' with 'em.

[manicmechanix]

That was my understanding that GM FWD wheel offset was mostly the same and between 35-40mm and 5-10mm offset difference was acceptable, but I put the Olds wheels on the Malibu with new tires and this resulted in the car exhibiting traits of the scrub radius being less negative and even postive-squirms over bumps and uneven road surface, braking cause steering input etc, all traits of more positive scrub radius. The Olds wheels just seem to stick outward from the car farther, and that would make the scrub radius more postive.

There's no way I can measure the offset now that the tires are on the Olds wheels and it wouldn't do any good anyway since I don't have the Malibu wheels anymore to determine if the offset is the same anyway. I can't find info on the offset for these wheels anywhere other than vague info that both wheels have the "same" GM "high" offset.