rgoodheart

Hey All,

New to the forums, just picked up a 2015 IS350 AWD for a daily use car. Love it so far, but a couple cosmetic issues: needs tint, and stock rims are too small and too inset (imo).

As its a daily use car, and AWD, my instinct is to run a square setup (seems odd to me that it's not from factory honestly). I would prefer not to lose width in the rear but based on my searches I'm seeing mixed things about fitting 255s up front.

My instinct is to run something like 255/30/R19 on 9et35 or similar: this results in a little less than an inch more poke, minimal change in clearance to the suspension (slightly less in the front, more in the rear), 0.25% change in rolling circumference in the front and 0.02% change in rolling circumference in the rear (based on the current 225/40/r18 8et45 front and 255/35/r18 8.5et50 rear stock setup). This should fix the cosmetic issue and allow for tire rotation without pulling tires. I can't imagine such a subtle change to rolling circumference should be an issue for the AWD/ECS systems.

However, 255/30/R19 isn't a common size, so more practically for both tire sourcing and ride quality, if a 255/35/R19 would work that would be better (a <4% change in circumference doesn't seem problematic given the f/r ratio isn't far off from factory, and a little slower reading on the speedo isn't a big deal).

Some searches people said that would fit up front, some said no. Saw a few comments about front caliper clearance on the IS350s as well. Hoping someone who has run/tried this can comment.

Don't plan to lower the car, won't be tracking it, don't want to modify the fenders. I have other vehicles for track use and hard driving, I'd like to keep this car simple, but it would be great to sort out the couple minor cosmetic things that I think it needs.

Thanks all!