Sportskid1

iTrader: (1)

I want to run a square setup for my track wheel/tire setup and I was thinking 255/35/40's all around might work out. It is not my everyday wheels, just for track days. I don't mind rubbing at full lock but don't want any rubbing under full suspension compression. I am running a 18X8.5 +35 wheel and am lowered to about 1.5 fingergap on BC coilovers with 12/10K spring rates. Anyone have any experience with this? I am thinking I may have to roll the front fenders but I am hoping the 255's up front are not so wide that they hit the upper lip of the fender under compression.

Gville350

iTrader: (10)

Not sure I've read of another member having that size up front. If I had the chance, I could put my rears up front to check for you (255/35/18 BFG KDWs on factory 18.5 wheels dropped on 12/8 BCRs).

I have read about a 245/35 tire being used; I think it was on an 18" wheel, but was only on springs.

Sportskid1

iTrader: (1)

Thanks for the offer Gville350 for the checkout but you don't have to spend the time to do that. The stock wheels have a different offset and I am sure we are running different camber and ride height so it probably won't be an apples to apples comparison. I know it is a pretty common setup in the IS-F side of things but I think they have different fenders up front with a bit more room. I was hoping that someone has been running a 255/35 up front for long enough in a 250/350 to give me some feedback to if it is even work pursuing. I might just look for a used set and start experimenting.

A 245/35 would be ideal but not alot of avaliability in that size. At least in the track tire world.

reyoasian

iTrader: (2)

I've actually been thinking of running 255/35R18 PSS on 18x9 wheels all around for a IS250 AWD lowered on RM springs with F-Sport shocks...however have been holding back as I'm worried bout the fronts...not sure what offset I should be running to make it work (if it can work)

ldc

Sorry to bring back this thread. But can aomwons tell me which to go with for square setup. I want to be able to rotate my wheels.

18x8 and +30

245/40 or 255/35 ?

redspencer

iTrader: (1)

For an 8" wide wheel, a 255mm tire will be too large to safely mount on the wheel. You'll need at least 8.5". If new tires need to go on a set of 18x8 wheels, you'll need to go with 245mm tires.

Regarding sidewall, a 245/40/18 tire might be too tall for the fronts and may rub (you can look through old threads to see if others were successful with this sized tire for the fronts). A 245/35/18 up front will work with no issues (I had this setup up front years back) but you'll be losing 10mm of width in the rear and the smaller diameter tires will likely have a negative impact with the VDIM and your odometer.

If you had 18x8.5 wheels, you could fit 255/35/18 on all four corners and would still maintain a close OEM diameter.

ldc

I'm worried the 255 will rub the inner plastic, will +30 offset help or make it worst. Oem is +4.

Also will the steering be stiffer with 255?

JLumbS

I am having issues right now with my front drivers side on both my IS250 and IS350, can anyone chime in