i know this has been asked many times but ive searched and couldnt come up with anything..

my question is why is it that s2000s come in 45s in the front and 40s in the rear..and most owners run this setup with their aftermarket wheels also..looks kinda funny to me..

im currently running 245/40/17 in the rear and 215/45/17 fronts.
wheel specs.
17x8 +44
17x9 +44

im in need of some new rear tires soon and would like to go with beefier 255/45/17s..

would i run into any kind of problems?
and this is for daily driving...not tracking the car or anything.

or what about these sizes. 245/45/17 and 255/40/17??

any help/suggestions or threads leading to the right answer would be greatly appreaciated.
thanks!!

 

The reason why is rolling diameter


Here are reasons why you would want to stay stock rolling diameter:
1) If you go larger your speedometer will read slower than you are actually going
2) If you go too large, your stock brakes may not be sufficient enough, because you will increase rotating mass. But more than likely you will be fine as long as you aren't throwing 20's or larger on it. lol

If you use this calculator to compare the front to the rear, you will actually find out that rolling diameter is similar and is less half a percent difference in size.

http://www.1010tires.com/tiresizecalculator.asp

I'm pretty sure the 45 in a 255/45/17 is a certain percentage of the overall treadwidth.

If you have not rolled your fenders and shaved your bumper tabs, you will also have to do that to keep the 255's from rubbing. But a 255/40 would be closer to rolling diameter than the 255/45

 

cool man.
thanks alot with the informative info ricepicker.

 

I would go with 45 series unless you live in an area where roads are very smooth.

 

?? The stock AP2 tires are 245/40/17. That's an even lower profile than a 255/40/17.

I'd run a 255/40. The 45 is going to look wayy too big.

 

Yeah, a lot of AP2 owners have moved up to a 255 vs a 245, but stick with the 40 series.

 

how would that be a lower profile? i thought the 245 was the width of the contact patch, 40 being the % of the profile and r17 being rim size.

wouldnt 255/40/17 just be wider and a little more bubbly than 245/40/17 on stock ap2 wheels? i dont see how this affects profile.

 

the 40 is a percentage of the first number. It corresponds to the height of the sidewall.

The first number is the section width in mm. Observe:

245mm x 0.4 = 98mm sidewall height.
255mm x 0.4 = 102mm sidewall height.

So the 245/40/17 is a lower profile tire than the 255.

Profile means a side shot. If you look at the 245/40 from the side, it is lower in profile than a 255/40.

255 is also wider than a 245...so the 255 would look more "bubbly". The stock CR size is 255/40/17. The rim size is still 8.5, IIRC. So 255/40/17 is very acceptable.