I've done searches. I've read lots of info. I even posted this question on My.IS, but nobody knew the answer.

Will 18x8 +40 with 215/40/18 tires fit, all around, without having to roll the fenders? I'm on coilovers so ride-height is adjustable.

 

you'll be fine homie.

 

https://www.clublexus.com/forums/is-...do-i-need.html

 

Thanks. But I've read that already, as well as through the 484738 page thread where it came from on my.is. But it doesn't really help... Going by the numbers, the size wheel I want will fit no problem. But some people were saying otherwise. I haven't been able to find anybody who have actually had 18x8 +40 on their car to corroborate.

 

You will be fine, i run stock wheels 17x7 +50 but I put a 15mm spacer front and 20 mm spacer rear so effective offset would be +35 front, +30 rear and it barely clears the fenders (no fender mods, no rubbing) with a few mm to spare.
According to this, http://www.1010tires.com/WheelOffsetCalculator.asp, Your setup should be fine as yours will be 3mm more aggressive in the rear and 8mm more in the front. Also im lowered with barely a 1 finger gap all around.

 

Thanks. What size tires are you running and what kind of camber? Because if you have to run like -3 degrees of camber to make the wheels clear then that's something to consider.

Also you can't compare a 7 inch wide wheel with a spacer to an 8 inch wheel's offset. Because your 15mm spacer moves your wheel exactly 15mm outward. But an 8 inch wheel with a +40 offset moves the wheel 23mm outward. I just measured the wheel clearance on my car with some calipers and 23mm is a LOT. So I'm worried about the clearance. I may have to roll the fenders or get a smaller wheel with a less aggressive offset.

 

Which is why the calculator is there, 8mm more poke in the front isn't that much, I was running like -2.1 camber in the fronts but I was having problems with inner tire wear, so i fixed it with a camber kit and got my car realigned to -0.8 in the front (No rubbing or anything whatsoever with new alignment). My rears are maxed at -1.8 camber but I never had any issues with tire wear in the rear. Also I run 215/45 all around, since your gonna run a 215 on a 8 inch it will be a slight stretch + a little bit more camber in the front should clear that 8mm difference.

 

Thanks.

The wheels I'm considering are Enkei RP03, PF01, and PF01SS.

The RPO3 would be 18x8 +40 or 17x8 +48.
The PF01 would be 18x8 +40, +45 or 17x8 +45

The PF01SS are really for the Honda S2000. But same bolt pattern. They only come in 17x8 +50. At least that's the closest that would potentially fit the IS300. Would need a spacer though, to clear the suspension.

I think the safest bet, for clearance, would be the PF01 17x8 +45. And with a 17" wheel, I'd keep some semblance of performance.

 

Go with 18's at minimum, don't go with 17's for aftermarket wheels because it looks too small on our cars. Trust me, you do not want to run spacers like I am, get wheels with the offset perfect for you so you don't have to run spacers. Spacers are like a hit or miss, i sometimes get vibration in the front because of the spacers alone (ichiba v2's), but I learned to live with it :\ Now my front spacers have like bent studs that need replacing, its just a pita to deal with(been running spacers for years now). Im just happy I dont have to run anymore spacers soon when I get my new wheels

 

Yeah, I think the +50 on 8" wheels isn't gonna work.

I'm fine with 17" wheels though, at least then my car won't be slower...

RPO3: 18x8 +40 or 17x8 +48.
PF01: 18x8 +40, +45 or 17x8 +45

 

18x8 +40 should be fine according to the calculator Im going with the same size in front and 18x9 + 42 in rear go with 225-40-18 in front

 

So you're on 18x8 +40 with 225/40/18 in the front and no rubbing? Did you roll your fenders?

 

18x8 +40 should be just fine up front.... depending on how low you are... with my old suspension (similar wheels specs), I did not rub at all... and I had 0 fender gap (tire was not tucking either).

 

no need to roll front fenders with those specs.

 

I run 17x9 +26 in the front and rear. I only needed a small roll and a ton of camber. You should be more than fine.