Coconut

I'm currently using the stock 255/40/18 tires on my 18x9.5" rear aftermarket rims, which has a slight stretch to them. It's time to get new tires, what size is recommended? I want to be as close to stock rolling Diameter as possible.

MY CAR:
18x8.5 +38
18x9.5 +38
F-Sport springs (~1" all around)

1. 255/40/18 (same as stock size, slight stretch, looks ugly)
2. 265/35/18 (2.81% smaller DIA than stock, increases fender gap)
3. 275/35/18 (1.77% smaller DIA than stock, might rub with F-Sport springs?, quite beefy for an IS250..)

Koz

I'm running a 275/35/18 and it works perfect. I have a 40+ offset and there no rubbing what-so-ever. Since I don't have to heet the tire, there is no waste at the drag strip. My 60 ft times are very consistant at approx 2.0 and every once in a while I get a 1.9. I am very pleased with this set-up.

Koz

Coconut

275/35/18 is closest to stock rolling diameter but wouldn't that look at bit too beefy and plus this is for an IS250.

Damaster32

iTrader: (8)

i running 245/40/18, cause with 255 i rub too much

four o two

iTrader: (1)

What's the offset? I have 275/30/19 on a 9.5+35 wheel out back with absolutely no issues. Could probably go 5mm more and still not rub. What's the point of getting a 9.5 rim if you're going to run less than a 265? You do realize there are plenty of people out there running as big as a 315 on a 9.5" rim, right? It's been done. Might be a little more sidewall bulge than what the IS crowd goes for, but it's possible.

I don't get the stretched thing. Unless I guess you like having less stability.

moo_juice

if your slamming your car on coils or air and want a flush/ semi flush look your going to need to stretch your tires in order to fit them.

If you stay on stock suspension or just about any spring drop you wont need to stretch tires no matter the offset.


To the OP, you said your on f-sport springs, but what is the offset, that can changes tire fitment a lot.

Coconut

updated first post with offsets.

I'm leaning towards the 275/35/18 since the taller sidewall will fill in the rear fender gap a bit better, I'm just worried it might rub. 265/35/18 would be perfect except the sidewall will be smaller than stock tires (see pic) and I don't wan't to make the fender gap any larger. Any input?

kloh7

iTrader: (6)

I had the same offsets on my Works. And 265/35/18 works great, tried a 275/40/18 and it rubs. I was also lowered on F-sports.

Koz

Be aware of the overall diameter of the tires, especially if you have an AWD. On an AWD all the tires need to be the same overall diameter. That said, if you have a RWD 250 you can stagger the wheel/tire size. The perfect size tire for a 9.5 wheel on an ISx50 is 275/35. It is just a little smaller (less then .5”) then the OEM overall diameter. You do not want to have a larger overall diameter tire.

Coconut

looks like I'll be going with 265/35/18. I don't want to chance 275/35/18 since it might rub, even on F-Sport springs.

Koz

The overall diameter will be almost an inch smaller.

Koz

Gerb

Do you guys think his tires look too meaty for 18inch? Maybe I should get 19 inch wheels.

MWIS350

I have seen someone with 245/40/18 front and 275/35/18 rear.

Nadim

heloo there i have a 2015 is 350 F sport and it's not lower at all. Everything stuck beside I will be putting my work vsxx wheels so need help with tire size 18x9.5+40 front
18x9.5+39 Rear
what tire should I get I was thinking 245/3518 front and 265/35/19 rear. So what do you guys think

ldc

I would prefer 19s and less wide tires than 18s with wider tires. 18s are ok but a tad small for the 250/350/F.