I'm looking into getting a set of 17x10's (Rear) and 17x8's (front). What backspacing do I need to specify to make the front's identical to the factory's backspacing etc. and what backspacing do I need to tuck a 17x10 in the rear without having to roll the fender lip or hack up the inner fender? I'm using a factory length thirdgen rear axle..... Any help would be appreciated!

4.5" in the front to match factory offset although you can go as high as 5" and still fit. 5.75" in the rear is about as deep as you can go. Here's 17x8.5, 4.5 B/S, 255/45 tire and a 17x9.5, 5.5, 285/40:

I have 17 x 9s up front with 275s, 4.5" bs & there is no way 5" of bs will fit. I can't fit a 1/2" wrench SIDEWAYS (the thickness of the wrench) between the wheel & the ball joint. I'd say there is 1/8" between them.

So will this work? - 17x8 (front) with 4.5" backspacing and 255/45/17

and - 17x10 (rear) with 5.5" backspacing and 315/35/17

?????

I need the rears to tuck as much as possible without rolling the fender lip, even if I have to do some inner fender massaging...........

Can I go deeper on the rear wheels' backspacing, like maybe 6"?

Thoughts?

I'd go 9" up front, with a 275. That's what I have & have no clearance issues. Tight, but never in any danger of rubbing & cutting a tire. With that 8"/255 combo, you'll have plenty of extra room.

315s you can do, but get out a BFH. I'm going 5.5" - 6.5", depending on just how much BFH work I wanna do.

One of these days, I'm gonna pull a rear wheel off, put on my spare rim & do some cardboard mock-up of 6.5" bs, & see just how much BFH is gonna be needed, before I decide on the final size.

Acually 6.5" backspacing in the rear wasnt that bad to do, were talking minor hammering, mostly around the passenger side inner wheelwell. Anything more then that then you really have to do some work. I don't see why 6" backspacing wouldn't work without anything being done though, if you want to go that route and might work better with the tire size your after.

For the fronts since your going with a 17" wheel your probably better off with the 4.5 BS, with a 18" wheel you can go more since you wont run into the problem that Stephen has. If I ever replaced my fronts I would go with a 8.5" or 9" wheel, whatever works best and run more Backspacing like 5" or 5.5" to keep the wheels nice and tucked in.

Have a look a my cardomain site for a general idea's what those Backspacings
look like on the car.

Size is 8x18 with 4.5 BS in front and 10x18 with 6.5 BS in back and a 245/40-18, 285/35-18 tire.

Just to be clear.....

I don't have any problems with my setup. I just would, if I tried to go any deeper inwards.

Well, 6.5" BS might not have been a problem since you went with a 285 tire.....

With a 315 tire on a 10" wheel, I'm starting to lean torwards a 6.25" BS. However, with the above specs, I'm still worried about the tire sticking out passed the fender AND how much inner fender work will have to be done..........

The 315's are made for an 11 in. wheel and I'll only have 10's, so the tire may bow out some causing inner fender rubbing...

Thoughts?

Me?

I have 275s front, 285s rear.....All on 17" x 9", 4.5" BS wheels. I can't imagine putting these 285s on a 2" wider wheel......

Your making me want to take the time to pull a rear wheel/tire combo & test one of my spare 17" x 9"/4.5" BS wheels & check clearances.....

So far from the research I've done, I'm leaning towards 6.25" BS for the rear (17x10's) with 315/35's.....

I ordered them with 4.5 bs for the front and 6.25 BS for the rear. I'm sure I'll have some inner fender work to do, but I think with the above backspacing, the 315's should tuck pretty nice!

Worst case scenario, I could always run a 1/4 in. spacer in the rear.......

mike, going away from the stock look? which rims did you order?

It's a secret! . I'll post pics when they arrive.

I think you might be ok with the 6.25 but will be a tight squeeze with the 315. Expect to do some hammering, also a aftermarket panhard bar might help keep things lined up if you don't have one already.