what is the difference between the two?
the reason why i want to know is because i think my rims are too thin (7inch) and i either want to upgrade to 225 (from 215) tires or get spacers to kick the wheels out more.
i want to do this because since the wheels are inside the wheel wells so much, you see a lot more space in there, therefor making it seem like the car isn't as low as it really is. i'm hoping that either the wider tires or spacers will take up the extra space and make the top of the tires flush with the wheel wells. thanks for the advice guys.

 

Offset is the distance from the mounting surface of the wheel to the middle of the rim, i.e. 3.5" from the inside of the wheel on a 7" wheel.

Backspacing is the distance from the mounting surface all the way to the inside edge.

 

gracias, exactly what i was looking for.

what do you think i should do to fill up that space?

 

Spacers are your only option besides getting new wheels.

 

what size spacers do you think i should get? my offset is 40mm. and the backspacing is 5.57". should i measure how much i think i need?

 

First, totally forget about backspacing - it's useless and going the way of the dodo. If you're sure your rims are 7" you should be able to fit 225 tires fine. I only know of H&R spacers, and they only make 5mm or 15mm spacers I think for the Max. Not sure if the 5mm one would be worth it, and the 15mm one should be OK, but it'd give you a funky offset of 25mm... might get more steering kickback (bump steer) because they're sticking out more with no more tire/wheel on the inside... but that's just a THEORY and I might be totally wrong and it'll be fine.

Stock offset is 35mm, just for reference. There probably are other brands of wheel spacers, but just make sure they're hubcentric.

All H&R kits require stud replacement (longer studs - makes sense right?) but there are ppl who have used cheaper spacers and stock studs. Don't know how smart it is to do this though.

 

what does hubcentric mean? how do you go about replacing the studs? is it something i would have a trained professional do? i want to get them on before saturday morning. thanks for all the info man!

 

If you take off the wheel you'll see a collar of metal sticking out around the dust cap in the middle. That's the hub, and the OEM wheels rest on it and the studs to support itself. A hubcentric spacer also rests on this hub to give it extra support. MaxGurl in your other thread has spacers like this I think. Replacing the wheel studs isn't something I know a lot about, but you'll most probably have to remove the wheel hub thingy (behind the brake rotor), then you have to pound out the studs and pound in new ones. Not sure how easy or hard this is, but you have to be comfortable with taking apart your brake/wheel hub assembly. Probably should use a manual for reference. Many people have done this themselves, but then again some people rebuild their engines too!

PS, it couldn't hurt to phone up a bunch of places to see how much it might cost to do...