My SC430 came with 245 70R18 tires. The speedometer reads low on distance traveled, and high on speed, suggesting the tire size is too small. Has anyone tried installing 255 70R18 tires on their SC430, and what were the results?

 

Wrong section. This is the SC400/300 board.

 

245/70/18? that an SUV tire size. you should be running a 245/45/18 or a 245/40/18.

go on tirerack or do a search on here for appropriate tire size for your car.