IS350 square setup
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.
Previously I would have said that would be no problem at all, and on an IS250 it wouldn't be, but ever since switching to an IS350, the traction control is much more sensitive to tire size variations! I am currently running a square setup on mine and it takes very little to get traction control to engage (it's seeing almost 4% slip at all times, so pushing it past that is very easy). The RWD IS250 on the other hand came with a square or a staggered setup, and it appears that the programming was very lax because of that. I had a square setup (245/40R17) for years on my IS250 setup.
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Jeff
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Jeff
Time to step up the tire sizes for the tree-fiddy then! Like you I run 17" wheels, my tires now are 245/40 on the front and 265/40 on the back. Seems to be close enough to stock diameters that I don't have an issue with traction control. I plan on stepping up to 255/40 and 275/40 next spring, we'll see how that goes.
As I don't have staggered wheels (as of yet), I will likely be doing 245/40 front and 245/45 rear, just to get the diameters corrected. If I get the staggered wheels at some point, I may do 245/265.
Jeff
Jeff
I'm running RE11A's, yeah. The RE71R is also available now, though I have been considering going to something a bit more street and less track such as the RE760 or Pilot Super Sport. It's up in the air, lol. The ZII Star Spec is also available in the sizes I am looking at.
Jeff
Jeff
Back when I had the 245/40 and 245/45 combo I had Pilot Stupid Sports. Great tires for what they are, despite my making fun of them. I would love to put RE71s, Star Specs, or Rivals on my car, but even with 17" rims they are going to be HARSH, even compared to the RE11s. My wife wouldn't appreciate that move. 
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I found the biggest difference going from the Z1 Star Spec to to the RE11A to be a reduction in noise. The harshness wasn't that much different. But memory is a fickle thing anyway, so who knows, lol.
Jeff
Jeff
Driver
Joined: Feb 2016
Posts: 199
Likes: 2
From: Ontario
Previously I would have said that would be no problem at all, and on an IS250 it wouldn't be, but ever since switching to an IS350, the traction control is much more sensitive to tire size variations! I am currently running a square setup on mine and it takes very little to get traction control to engage (it's seeing almost 4% slip at all times, so pushing it past that is very easy). The RWD IS250 on the other hand came with a square or a staggered setup, and it appears that the programming was very lax because of that. I had a square setup (245/40R17) for years on my IS250 setup.
:\
Jeff
:\
Jeff
Back when I had the 245/40 and 245/45 combo I had Pilot Stupid Sports. Great tires for what they are, despite my making fun of them. I would love to put RE71s, Star Specs, or Rivals on my car, but even with 17" rims they are going to be HARSH, even compared to the RE11s. My wife wouldn't appreciate that move.
Jeff
Following up on this, it actually looks like the 245/40 and 245/45 combination is actually a larger difference F/R than stock. Did you have any issues at all with this setup and traction control/VDIM? In theory it would cause the traction control to kick in slower than stock, but I don't want to regret buying them, haha.
Jeff
Jeff
Driver
Joined: Feb 2016
Posts: 199
Likes: 2
From: Ontario
In this case if I don't want it completely off, will it help if I get a isf steering ecu and use the isf sport vdim setting so it would kick in later?
