I know this is a really basic question, but for some reason I'm having trouble wrapping my mind around this. Say you have 2 wheels of the same diameter and width. Will the wheel with the lower offset number in the specs sit further out on the car? In other words, will it give the car a wider stance? For some reason it just seems like it should be just the opposite.

 

HiRever, you are right. The lower offset number pushes the rim farther outward, and it is hard to wrap the mind around.

See if this helps:

Offset is the distance between hub mounting face and the wheel centerline. More (+) offset moves the hub face closer to the outside edge of the rim. Less offset moves the hub face farther in toward the rim center, so the rim sticks out farther.

 

Thanks, Ned. It still seems backwards to me, but I think I'm finally starting to grasp it. I actually even stumbled on an example at yawpower's site. He says his wheels have an offset of +40 "for a little wider stance". As we know, the RX-8 OE wheels are +50, so there you go, lower number, wider stance.

 

It's all explained in the Tire Rack Tech Center. Here's their offset article , including diagrams to illustrate.

Regards,
Gordon

 

OK, so, if I were to look into purchasing some different wheels, I would need to stay with the stock of 50MM offset OR to go slightly further out such as 40MM or 45MM? If I read Tirerack's offset guide, the lower the positive offset number, the further the wheel set out from the brake rotor. Is this correct? As I am looking into new rims for next winter for winter tires, I haven't seen any with the 50MM offsets the stock has.

 

If you stay with an 8" wide rim and a 225mm section width tire you should be able to go down to a 40mm offset with no problems. For e.g., I just mounted 18x8" Enkei's with 42mm offset and 245/40/18 tires, and there is still sidewall clearance at both front and rear fender lips. I believe a couple of people on the forum have used 38mm offset with no problem on their winter rim sets. Have a browse around this section.

 

Actually, I am not planning on staying with an 18" wheel and tire for the winter. I was thinking a 17x7" wheel with a 40-45mm offset. This seems to be a size that is common when looking at 17" wheels. I also read on here that going a bit narrower for a winter tire provides better traction than a wider one for cutting through the snow.

Even though I have read that narrower is better in snow, way back in the 70's I had a VW Bug that I had placed G50/14s on and weren't snow tires but had an aggressive wide tread, I never had any trouble in winter, it was like a tank. Of course the engine was on the drive wheels providing a lot of weight for traction. I had left the very narrow stock sized tire on the front and it cut a path through the snow like a ski. That was a different car and a different time, though.