245/40/18 Instead Of 255/40/18?

[07Black&Tan]

07 IS350 has summer tires on it. Got it from San Antonio last week and they simply will not work in the KS winter. I'm looking for some good A/S tires, and have been really looking at the Bridgestone 960AS and the Goodyear F1s. What's the question you may ask.....well the 960s don't come in a 255/40/18 for the rear wheels. I'm wondering if anyone has put a 245/40/18 on the rear wheels on the 18" staggered setup on a 350. I guess my biggest worry is the sidewall height and how that could affect the car's comfort, handling, and how it sits.

I have considered getting winter tires, but I'm not really up to having 2 sets of tires and really don't have anywhere to keep them during their off-season.

If anyone has any input on this one I would greatly appreciate it.

Thanks in advance.

Also, if you have thoughts or opinions on the F1s, holler, I have heard they have some awful road noise problems.

[ArmyofOne]

07 IS350 has summer tires on it. Got it from San Antonio last week and they simply will not work in the KS winter. I'm looking for some good A/S tires, and have been really looking at the Bridgestone 960AS and the Goodyear F1s. What's the question you may ask.....well the 960s don't come in a 255/40/18 for the rear wheels. I'm wondering if anyone has put a 245/40/18 on the rear wheels on the 18" staggered setup on a 350. I guess my biggest worry is the sidewall height and how that could affect the car's comfort, handling, and how it sits.

I have considered getting winter tires, but I'm not really up to having 2 sets of tires and really don't have anywhere to keep them during their off-season.

If anyone has any input on this one I would greatly appreciate it.

Thanks in advance.

Also, if you have thoughts or opinions on the F1s, holler, I have heard they have some awful road noise problems.

road noise is awful from what i have heard as well, head over to michelin or bridgestone for high quality performance tires...hell even BF goodrich with the Traction T/A is better and quieter than those.

[steviej]

Speedometer

Assuming that the 245 tire is OEM tire and speedometer readings are correct When speedometer reads 60mph (96.6km/h) actual speed will be 60.7mph (97.7km/h): 1.2% faster with the 255 tire. Tire shops don't like to mount anything that yields greater than a 2% change.

Suspension Clearence

Assuming that the 245 tire is OEM tire and there is no problems with clearance on both sides, then the clearence on the 255 tire will be the same.

Fenders

The 255 tire will stick out 10 mm (0.4'') farther which is acceptable for most cars.

Wheelwells

The 255 tire will fill out the wheelwell by extra 4 mm. Almost no difference

steviej