n20blkz, do you have any pics of this, just curious?

 

No, I don't. I'm trying to get set up to post digital pics sometime soon.

 

Well I just orderd a set of 315/35/17 Nittos for my 17x9 ZR1 style rim from Discount Tire. I repeadily ask them if there is any issues I will have from running that size tire on the 9" wide rim and they repeadily told me that the Nitto will not have any problems on it. I said if there is a problem like a lot of knowledgable people on my camaro boards state I might have, then I will want my $$$ back. They said not a problem. As far as me being to worried about how it wears, I don't care cause the car only sees about 500 miles a year anyway. My buddie runs the tire on his '03 Cobra and it looks good....
We'll see I guess...

 

Try more like 1.57" difference

 

It varies from model to model, but there is usually a good 1.5"+ difference in section width (the actual tire width) between a 275/40 on a 9.5" rim and a 315/35 on an 11" rim. Tread width will also vary from model to model, but on the same rims the difference will usually be 1-1.5".

Also, if you are putting a 315 on a 9" rim, remember than the section width will be significantly smaller than the specs on that tire using an 11" wheel. Using the general rule of thumb, there is approximately a .2-.3" reduction in section width for every .5" narrower than the measured rim width (11" for a 315). So, if mounting a 315 on a 9" wheel, you will be reducing the section width by .8-1.2". While the tread width will not be reduced by the same amount due to the design of radial tires, it will be reduced somewhat and may cause improper wear (faster wear in center or sides depending on pressure).

 

Could be urban legend, but I've always heard that putting a tire that is too big for the wheel will result in the tire bulging in the center, therefore creating LESS contact patch than a properly sized tire on the same rim.

 

You can do it but ONLY with a Nitto Drag 315/35/17. They're narrower than any other brand out there. WHY? I have no clue. Any other brand and I would put that size on anything less than 10.5"...11" being the best size.

I can say this because I run this nitto drag 315/35/17 on 17X9.5" ROH Rims and they're definately safe and have a nice look. If I were in your position...and if you're looking for opinions, I'd use a BFG Drag 275/40/17 or the new Mickey Thompson ET radials if they're out now. It'll stick better. Price wise you'd be spending more obviously, goodluck!