18x8 18x9 staggered wheel tire size, anyone help?

[B6B]

anybody assist in what tire size i should run to keep the same rolling diameter? wheel size is 18x8 and 18x9, not looking to stretch and i have a nice set of 235/40's so if i could use 2 of those on the rear i'm thinking maybe 225/40 up front?

searched and found a few calculators and didn't see one that accounts for rim width and found a few threads with much more hardcore stagger setups than mine.

[Crusty128]

As weird as it appears, width does't have any impact on rolling diameter. Even stretched like hell, wheel keep the same height.

Just go with the same tires specs both front and rear please.

[B6B]

hey thanks, i just found this on tireracks site

"The width of the rim will influence the width of the tire. A tire mounted on a narrow rim would be "narrower" than if the same size tire was mounted on a wide rim. NOTE: Because the overall diameter of a steel-belted radial is essentially determined by the steel belts, there is little, if any, change to the overall diameter of the tire due to differences in rim width."

in my brain it made sense that stretching the tire wider would lower its od, but i guess im wrong. looks like i wont need any new tires

[B6B]

the more i think about it, the more sense it makes.

[A4 Quattro]

As weird as it appears, width does't have any impact on rolling diameter. Even stretched like hell, wheel keep the same height.

I'm but positive this is true. I've heard both sides of this argument a dozen times.

[J.the W.]

You'll be fine with a 225 front 235 rear. That's what I'm running stretched on a 9.5" front and a 10" rear.

[LJH]

Question is why would you run a staggered set up on this under steering relatively low powered car? If you want to run a staggered set-up buy a Different car....form follows function.

Cheers,
Jim

[MidwestB6]

225/40r18 = circumference of 78.8 inches
235/40r18 = circumference of 79.8 inches

Please get the same tires on all four wheels, not doing this will destroy your center diff. If you want it to look wider in the back, get wheels with a lower offset.

[dparm]

225/40r18 = circumference of 78.8 inches
235/40r18 = circumference of 79.8 inches

Please get the same tires on all four wheels, not doing this will destroy your center diff. If you want it to look wider in the back, get wheels with a lower offset.

Correct, you do not want to run different sizes from and rear. It puts extra strain on the center differential.

I suggest running 18x8 all the way around (the stock size) and using a 235/40R18 or 245/40R18 tire. Don't try and cram huge wheels with skinny tires on there. It's unsafe and looks ridiculous.

[B6B]

its been established higher up in this thread that wheel width does not change outer diameter of the tire, so as long as all 4 tires are the same size staggered rim width will not harm the center differential and looks way better than square set up to me. i dont really think 18x9 with 235/40 really fits into the huge wheel with skinny tire category.

[dparm]

I have to disagree. 235 tire on a 9" wheel is too small. 9" wheels typically run a 255 tire for a squared-off sidewall, or maybe a 245 at the smallest. Your rotation options are also limited by going staggered. I don't really see the point of running a wider wheel on the back with the same size tire as up front. But hey, it's your car and your wallet.

[MMMB00ST_A4]

245 on a 9" wheel is a "squared sidewall. 255 will sit wider than the wheel itself and will only serve as a bit of a "curb guard".

[MidwestB6]

Did a bit of searching, here's a C5 with 18x8.5 fronts and 18x9 rears. http://img26.imageshack.us/img26/8759/mg2550.jpg
Same car with 18x8.5 fronts and 18x10 rears. http://img705.imageshack.us/img705/2717/imag0356i.jpg

Or maybe more relevant... check out the B6's in posts #163 and #164... http://www.audizine.com/forum/showth...=1#post8162434

So what you want to do can totally be done. A lot of us are going to disagree, but who gives a damn what we think?

[mcbrown35]

18 x 9 with 225/40 ZR18 BFG Sport Comp 2's

I ordered 255's and Discount Tire messed up and put on 225's...

[mcbrown35]

255's on now.. and am rubbing in front... may drop to 245's