getafewliv

I know there are a few threads regarding this question, but I couldn't find a solid answer or hear form anyone's personal experience.

My TSW wheels have a lower offset that prevent me from going as low as I want with the stock tire sizes. I also am not a big fan of the thicker profile in the back vs. the front. I am looking at buying a set of Continental Extreme DWS tires and getting rid of my summer tires and my stock wheels/winter tires. Too much hassle for the weather in Vancouver.

I know the diameter difference is about 3.86% smaller, but I have read that because the IS350 uses all 4 wheels to calculate speed, the difference will be less of an issue.

Has anyone ran the lower rear profile on their 2IS and did you notice any issues? Any traction control issues or what not?

minato

iTrader: (1)

what will you be running up front ?
are you just changing stock rears ? so you will be running stock fronts ? 225/40 ? if so you should be fine
im running 235/35/19f 275/30/19r and no issues , im 250awd

scott1256c

In winter I run 225/45/17 all around. What "issue" were you expecting? I mean I know I run slower than the speedometer shows. It isn't that much though. Maybe 5 click at 80kph.

BTW 225/45/17 is pretty much the same as 225/40/18. About 3mm difference in height which is negligible.

Lex_Giorgio

Your car is designed to have 225-40-18 in the front and 255-40-18 in the rear. The 3IS runs a 255-35-18 in the rear.

Here's what will happen if you run the 35 profile on your 2IS:
Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
255/40-18 4.0in 13.0in 26.0in 81.8in 775 0.0%
255/35-18 3.5in 12.5in 25.0in 78.6in 806 -3.9%


On another note, I'm still puzzled why people run a staggered setup on an AWD car...

Lex_Giorgio

Just some other info:
Front:
Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
225/45-17 4.0in 12.5in 25.0in 78.5in 808 0.0%
225/40-18 3.5in 12.5in 25.1in 78.8in 804 0.5%

Rear:
Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
225/45-17 4.0in 12.5in 25.0in 78.5in 808 0.0%
255/40-18 4.0in 13.0in 26.0in 81.8in 775 4.2%

getafewliv

Yep, all info I have found. But my issue is that I have read that the VDIM system may not like the change in speed on the rear wheels and it can cause issues with it. But whether it is anything significant or noticeable is what I am curious about and if there's any significant downside to going to a lower profile in the rear to even out the wheel sizes and allow me to lower my ear end just a bit more.

Lex_Giorgio

Well I run a 225-45-17 on all 4 corners in the winter and in the summer I have a 225-40-18 up front and 255-40-18 in the rear. My IS250 is a RWD. No issues.

And next winter I'm planning to run a 225-40-18 in the front and 255-35-18 (3IS setup) in the rear. You're going to be fine.

Jeff Lange

iTrader: (1)

IS250 models came with staggered and non-staggered sizes, the rest of the vehicle remained the same. I am running 245/40R17's all around on my RWD IS250 without issue. VDIM seems unaffected. I know of other IS250s that came with 205/55R16's all around that switched to the staggered 225/45R17 / 245/45R17 also without issue. Lexus even did this when installing accessory wheels on these models.

In short: it'll be fine.

Jeff

getafewliv

Sounds good. Looks like I will be switching to 255/35/18 when I get some new tires.

Thanks for the input everyone.

Sportskid1

iTrader: (1)

I run a 255/35/18 on my 08 is350 and have no issues. Running 18X8.5 +35 wheels all around. Seems to work fine.

Damilola

you re on 235/35F and 275/30 R

what I wanna know is are u on 19x8 all round or what is the width of ur rims?

i have 18x8 all rounds but will it make sense to put 225/40/18 F and 255/35/18 rear?

by the way, my car is 2007 IS250 AWD