what is the biggest tire sizes (width and height) you can fit on the IS300 in the front and back?

thanks

 

well for the widest a certain individual has 12" on the rear on his IS300, so to make it easy i'm going to say the widest is 12". lol!

 

That is not a fair statement. The 12" wide wheel will not fit on the car with out completely rebuilding the rearend of the car.

To be fair a 10" wheel in width would be doable but would be a stretch.
There are certain variables that have to be asked and taken into consideration.

Suspension setup
Diameter of wheel
Offset of wheel

All of these are a factor which must be taken into consideration for an accurate answer to your question.

 

Well... width and height. I've got 20s on mine. 1 suggestion, don't do it. I had to cut a lot to get these in there. There are plenty of guys with 19X8.5 fronts and 19X9.5 rears. Those seem to be the safest without heavily modifying the fenders. as for tires, 235/35/19, and 265/30/19 front & rear.

 

that's really too bad that the IS' wheel well doesnt' allow for much more tire/wheel than a 10" wide!

with a 6spd GTE swap, mega power can be possible and you'd need as much tire as possible !

 

as you are asking for tire size, it would really depend on what size rim you are asking tire size for... a lot of us for stock rear fenders, without mods, probably a 275/285 tire could fit. most common tire for 19's is usually a 265/30/19 which is what i will be running, but im currently running a 255/35/19