Yet another ET question, but an easy one i think..

[Valve_Cover]

So I've tried understanding the wheel width calculators floating around here but my head goes all fuzzy when I try to figure this stuff out...basically all I want to know is if a 9.0'' wide 18'' wheel with an offset of 48 will fit in the back on our cars. Or will I need spacers, wheel bolts, fender rollage, etc...I currently have OEM sport suspension, and will probably be running coilovers come spring, but no major slammage in mind though, just a tad lower than stock sport.

wheels in question: the fronts should fit fine right ? ( 18x8 et45)
http://www.raderwerks.com/product/ag-310-gm

[onceover]

Ive test fitted some 18x9 ET35's and theyre flush with my rear fenders, an ET45 will be tucking slightly, so youll be fine

[Valve_Cover]

yea they are actually et48, not 45, should still clear? And if they tuck i can just run a small spacer and be in the clear right?

[onceover]

http://www.1010tires.com/WheelOffsetCalculator.asp

An ET48 will tuck even more than a 45. Best way to go about buying spacers is mounting the wheels and measuring how much further out you want the wheel to stick out

[Valve_Cover]

yea i was using that calculator but I just came across the actual definition of what and how an ET works here:
http://en.wikipedia.org/wiki/Offset_(wheel)
And it really helped clear things out. From what i can tell an et48 wheel in a 9'' will need something around 10mm's to be flush to the fender. I want it flush, no poke or tuck so I think thats what i will be going with. And I've always wondered what ''ET'' meant, it actually means Einpresstiefe (In german) or ''insertion depth'' in english. fun fact to know!

[alpinevr]

I would go with a 15mm spacer in the rear and a 10mm in the front. I'm running 19x9 et29 and sit pretty flush with my fenders

[alpinevr]

And it also depends on what size tire you want to run to decide on the size of spacers you should use

[Valve_Cover]

And it also depends on what size tire you want to run to decide on the size of spacers you should use

I dont want to run any wider than stock width so 235-18. I imagine I'll be getting just a tad of stretch on a 9inch wheel, and not really any on the front 8''.

[CyberPMG]

Definitely get spacers. ET48 is too far in. The USP 18x8 wheels have an offset of ET43. 10mm spacers up front and 15mm spacers for the rear should work.

[mister_tu]

18x9's et30 would be perfect