BK: 17x8.5, 245/40/17, offset = ? Experts plz halp!

[Bimmerman]

I've recently gotten fed up with my M3 track car, and want to sell it to build the Legacy to pwn all legacies. I have a stack of brand new unmounted Dunlop Star Specs in 245/40/17, and if I sell the car I'd rather put those tires on the Leggy (it's a 95 BK).

The leggy has stock struts and springs, Whiteline front bar, IPD rear bar, and whiteline end links. I plan on installing either Ground Control custom coilovers or RCE Tarmac2s in the near future before I try using these tires. The tires fit perfectly on a 17x8.5, so I was thinking (and read as much as I could on here) of putting the Dunlops on a set of 17x8.5 wheels for the Legacy, I just haven't a clue what the offset should be. I have no qualms about rolling and pulling my fenders. I know the tires aren't Hoosier absurd wide, but they're not exactly skinny either.

So: what offset do I need to run 245/40/17 Dunlop Star Specs on a 17x8.5 wheel? Is this even doable?

Cheers!

[Huffer]

With stock struts and springs, you are going to need to push the mounting face pretty close in to the center of the wheel, so a lower offset is going to be needed. But seeing as you are going with coilover suspension or the like, this will also net you some additional under fender clearance.

I'm thinking that with the stock suspension you'd need a +35 ET and with the RCE Tarmac2's you'd be ok with some +40 ETs. The issue is going to be the amount of body-tire compression you get as you corner, and where it's going to rub then.

My recommendation is to not even bother with rolling and pulling fenders, but to just cut them and bolt on some flares. I have a friend that runs 13x10" race wheels for Autox, and just installed some universal S14 flares (?) on his GC Impreza.

Caveat: I'm typing this on 3hrs of sleep so I could be completely backwards.

[Okin DaVanh]

I think you're spot on Huff, but some tweaking here or there "might" work wonders.


Check this out to see if it helps:

viewtopic.php?f=12&t=12004&p=136252&hilit=wheel+fitment+guide+rim#p136252 (https://sl-i.net/FORUM/viewtopic.php?f=12&t=12004&p=136252&hilit=wheel+fitment+guide+rim#p136252)



Also, if you're parting out the Beemer, let me know.

[sybir]

I ran 245/40/17 Hoosiers on a 17x8.5 ET45 on my wagon - like you said, the Hoosiers are a bit wider, but not by much. I was ok under most conditions in the front, but rubbed the fender pretty regularly in the rear with any weight in the car, and that's with really high wheels rates (springs in the rear were 10k's). I have a pretty signiofacnat roll and pull int he rear, and a roll and mild pull in the front. One inner sidewall very, very lightly buzzed my coilover under hard cornering, but it was enough to rub dirt off the threads and that was about it.

I'd think with a "normal" 245 and a reasonable ride height with stiff springs you'd be ok with a slightly higher offset than a +40, because you run out of room on the fender side really quickly. These cars just have less room than a WRX.