I went to tire rack looking for them but they didn't even have it listed yet.

 

215/45/17 (as on JDM TRD ist wheels)
225/40/18 (as on USDM TRD wheels)
225/35/19 (only .5% difference from 225/40/1

 

will those numbers keep the speedo correct?

 

So 215/45/17 is the same height as the OEM rubber? Thanks

 

Silly question but... does the size of the tire determine the rim you can get? I mean I know that if you get a 17" rim you need a 17" tire, but I'm more asking for the width of the tire and the other stuff. Want to buy rims+tires but don't want to screw myself over lol.

 

Most the time YES. There are those that like to stretch a skinny tire onto a wide rim tho.
Basically here is a tire size calculator to use when wanting to match up tire sizes and wheel sizes. Have fun!
http://www.rims-n-tires.com/rt_specs.jsp?postId=906

 

Overall diameter will be different than OEM (slightly smaller), but that's what they use on JDM iST, so that's as close as it gets. I tried 215/50/17 and it was a tad too big (1-2mph discrepancy on the speedo), so 215/45/17 should be good.

 

Well, if you want 17" wheels, get 215/45/17 tire and a 17x7 wheel with offset between 45 and 35. That's the safest bet.

If you want to get creative you can get a 17x7.5 or 17x8 wheel, but then you'll have to be more careful with offset, and these wheels are usually harder to find and are more expensive. So before you are ready to experiment stick to the safe choice.

 

Ugh math, we've hated each other since the beginning.

Ok so when I look for tires I'll be looking for 214/45-35/17. Now all I have to worry about is finding the right one and not having the monies ;)

 

No. You are looking for 215/45/17 tire and a 17x7 wheel with offset that's between 35 and 45mm. Two very separate sets of numbers.

 

Ok so the 45 can't change to 35 then.

Gosh wheels are hard.

 

The offset refers to the backspacing of the hub mating surface relative to the centerline of the wheel. In tire sizes, the 45 in 215/45-17 refers to the aspect ratio (and as such is unitless) of tire width (the first number, in mm, 215 in the example) and the tire side wall height (from tread to tire bead/wheel rim). In looking at wheels, the offset is often preceded by "ET" such as "ET45". This better indicates what the number is referring to. So, the offset refers to the wheel and the 215/45-17 refers to the tire. To know if you can use a wheel with a tire, it's the last number that's important, 17. In both cases, this measurement is in inches and refers to the diameter, essentially the size of the tire and wheel mating surfaces.

To confuse things a little further. A numerically smaller ET moves the wheel further away from the car. Therefore, if a 17x7 (rim width) ideally should be ET45. Then a 17x7.5 should ideally have a small ET to keep the added width centered in the wheel well. If 0.5 inches is 12.7 mm, subtracting half to maintain center, the ET should be ~38. But that does assume there's equal room on either side of the original tire and wheel. Gaging from the specified range of 35-45, that says there's more room outside than inside, thus a wider wheel could go to an even smaller offset, pushing the extra width more to the outside. Perhaps 35 or even 32 for a 7.5 inch rim. But you don't want to experiment too much because it can get awfully expensive.

Best thing to do is go to Tirerack or Discount Tire and find a couple of choices that they say fit. If they tell you wrong, they have to take them back. And then you don't have to worry about all this mumbo jumbo.

 

You really didn't have to complicate it that much. ;)

 

Meh, I'll just take the easy way: Ask others to help me and I'll learn along the way.

 

well at least that gave ME and idea of what that was..lol thanks. I'm actually interested in 20" wheels or 19" wheels i would like to know tire size (measurements) and offset please???