Jeff Lange

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I have been running 245/40R17 all around on my RWD IS250 on the stock 17x8.0 +45mm wheels for several years. They fit delightfully, though I think a slightly lower offset might also fit very well, or a slightly wider wheel. 245/40's fit pretty nicely on 9.0" wide wheels. You do need to be careful on fitment for the front calipers on the IS350 though, they are a very wide caliper and are not mounted that far out from the hub. JZA80 Supras have similar fitment issues in the front as well.

I am running the factory sport suspension with F-Sport sway bars, so I am not close to rubbing at all. Lowered cars may have a bit tighter fitment on the front if you're running wider wheels or a lower offset.

Jeff

Sportskid1

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Just picked up some konig milligrams in 18X8.5 +35 all around which I found for cheap. Not a huge konig fan but these are made with the same MAT process that Eneki uses for the RPF1 and weight just over 18lbs and are suppose to be pretty strong. Going to play with them and see what I can get to work. Just put my current NT-05's on them for now (225/40 front and 245/40 rear) until I kill them which will probably be the end of summer. Hopefully the +35 offset up front isn't to aggressive but for the price I though I would give them a try.

Byprodrive

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I have 245/40/18 Michelin Super Sports on the front of my 07 IS350 & 255/40/18 on the rear. Stock suspension & X-pac wheels. With more than 1 person in the car front tires rubs slightly with steering turned full lock to the side. Currently installing oe sport springs & F-sport shocks. I will let you know if this changes clearance.

Sportskid1

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Got the Konig Milligram's mounted up. 18X8.5 +35 all around. Shaving 10lbs a wheel really makes a difference. Currently running my old Nitto NT05's with 225/40/18 in front and 245/40/18 in rear. I am going to play with it and hopefully try and run a square 255/35/18 setup for my next go around. I put one of the 245's up front and it is pretty much flush with the fenders but I didn't drive around on it so I need to do a bit more experimentation. I think with the lower profile 255/35 tire I would have a bit more room for the extra width. Might have to roll the fenders though. We will see

JETLEX

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@Sportskid1 - looks good! Do you mind sharing your alignment settings, specifically camber in the front?

TIA!

Sportskid1

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Running -2 deg camber up front and -1.5 in the rear. 1/16 toe front and rear. Not sure what the caster is but it's not adjustable anyways. Seems to be a goof track/street setup for now.

Sportskid1

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Finally burnt through my old track tires and found a nice set of 255/35/18 R888 take offs for a cheap testing setup. Mounted them up and gave them a test fit in the front. Complete success in the initial install and an afternoon of driving around town. Tires sit about 1/4" inside of the fenders (Near flush). No rubbing at all from lock to lock. Nothing hits on speed bumps and as of now I would say I could live with them as my daily driving wheels (these are track only wheels). I haven't done any aggressive driving yet but hope to get to the track in a few weeks for a full go at it. So glad they fit. I will be so nice to have the ability to rotate from front to back. My tires will last so much longer. Here are my stats if anyone is interested

18X8.5 +35 Wheels
255/35/18 Toyo R888 at all 4 corners
Running about -2 deg of camber up front
Lowered to about 1.5 finger gap ob BC coilovers

redspencer

iTrader: (1)

It's nice to hear that the 255/35/18 tires will fit up front. I'm also running 18x8.5 +35 wheels on the front but with a 245/35/18 tire size since I wasn't sure if the 255s up front would rub or not.

You're definitely going to get more mileage out of your tires now that you're on a square setup!

valeoray

Wouldn't an aggressive offset affect the scrub radius too much. What affect would it have on the steering?

jdubbsISF

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I just did some open lapping yesterday in the Lexus for the first time. I wanted to learn the limits of the car because I knew my old car really well. Running the tires that came with the car (will sell them before winter) which are Yokohama Avid Envigors. Using the OEM 18" staggered wheels, 225/40/18 and 255/40/18, The tires were quite bad and thats what I expected anyways. No rubbing, as there shouldn't be. But they were fun to drift and got surprisingly good lap times. Everyone at the track underestimated my IS350 by a lot. But anyways...

I bought 19x8.5 and 19x9.5 +38 RPF1 for next year. This thread gives me hope as the wheels currently have 245/35/19 and 255/35/19 Falken 452. Most other threads I found said that anything wider than 225 in the front would rub, practically guaranteed.

Sportskid1

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I am hoping that will not be to much of a problem. But 35 offset isn't to aggressive. I am getting a lot of understeer and push out of the front and I am hoping the additional width of going from a 225 to a 255 will fix that. We shall see.

I ended going with the 255/35/18 as it was the same diameter (height) tire as the stock 225/40/18. In my research most people who were running a wider tire were rubbing do to the additional height of the tires not the width. Especially with the lowered cars. My concern with a 245/40/18 or 245/35/19 is the tires is about 0.8inchs taller than the OEM size and that is were people were having issues. Only one way to find out though. Put them on and see if they work.

Sportskid1

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Just wanted to give everyone a status update for anyone else interested in running a 255/35/18 square setup. Did a track day last Sun and the setup worked great. No rubbing or anything running about 1" gap and -2 deg of camber on my 18X8.5 +35 rims. Car handled so much better and I could take the corners so much harder. Very neutral handling now. Wish I did this a long time ago.

pmanliu

iTrader: (4)

Got pics? Would love to do a 255 also

Sportskid1

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Pics above on post #22

rigid9

I'm really happy I saw this thread. I recently sold my s2000 that I autocrossed / tracked and will be picking up an IS350 soon. I still have motorsports in my blood so I've been looking for a thread exactly like this that shows a more track oriented setup.

Thanks for posting!