is this wheel tire combo feasable - not on list

Don't know if there's a difference in the back wells of these cars, but I WAS running 245 50's on a 15x7 wheel, and it rubbed on every bump I hit, if I had a passenger. If I was by myself, it took a hard bump to get it too do it, but I finally took them off. Sounds like a good price, but if you can't use them, they are worthless to you .

I can only give my opinion.

Not in the front.

I run 245 40 17 on the front of my 65 now (upgrade from the 245 45 17).
I run them on a 17x8 wheel with 4.75 backspacing...the equivilent in 17x7 would be 4.25 backspacing and while I have not rolled my lips in the front, I run aggresive alignment, drop springs, shelby a arm replaced, and now also relocated ball joints (thanks opentracker).

actually Nick, i think you're working backwaqrds on this one. with his current combo he would 3.00" inch of wheel sticking out toward the fender, with your combo but you have 3.25" sticking out towrd the wheel correct? so he would have 1/4" more clearance than you have now correct? masybe i'm just lokoing at this wrong, it's late and has been a long day.

bnickel said:

actually Nick, i think you're working backwaqrds on this one. with his current combo he would 3.00" inch of wheel sticking out toward the fender, with your combo but you have 3.25" sticking out towrd the wheel correct? so he would have 1/4" more clearance than you have now correct? masybe i'm just lokoing at this wrong, it's late and has been a long day.

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I had to think about this one for a minute too, I admit, but the difference is that Nick is comparing tire clearance whereas you're comparing wheel clearance, which are two different things. Nick is saying take 1/2" off each side of his 4.75 inch backspacing due to the fact we're talking about a 7" wheel versus his 8" wheel. So, to mimic Nick's setup, you would need 4.25" backspacing on a 7" wheel and the same size tire should work. The poster said he had 4" backspacing, so it appears that it would not work. Still, it might possibly work with rolled fenders, which can give you about 1/2" extra clearance on each side if rolled flush, assuming his suspension was setup like Nick's.

One other thing that was not mentioned that I have questions about, however, is that this is not, so to speak, a straight-line equation. Correct me if I'm wrong, but I believe the ideal width of a 245/45-17 is greater than 7". A 245/45-17 would have less sidewall bulge on an 8" wheel than it would on a 7" wheel. Is it possible that a tire that is theoretically too wide for a wheel would actually be wider than the tire mounted on a wheel that fits the width of the tire better? I doubt it, but it would certainly make a difference as to the overall width of the wheel and tire combo either way, although I suspect it would be slightly narrower, especially at the top of the tire where you would normally encounter rubbing. However, that would effect the answer to this question and could make a difference given the close tolerances we're talking about.

i will throw in my $.02, 245 is too wide for a 7" rim. 225 or 235 would be about perfect... and this helps out for tires on a budget...as 225 &235 17's are pretty common import car sizes... with about a million more options available for price.

65up2d8 said:

I believe the ideal width of a 245/45-17 is greater than 7". A 245/45-17 would have less sidewall bulge on an 8" wheel than it would on a 7" wheel.

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This is hard to say. A quick survey on tirerack.com shows that the recommended wheel width for a 245 45 17 is 8 inchs. And the manufacturer recommended rim range that it can be installed on is 7.5-9 inches which means you are pushing the limits a bit putting it on a 7 inch rim. GENERALLY speaking though when you install a tire on a narrower than recommended rim the side walls suck in as they stretch to make a bead on the rim. The tire then also crowns in the center. This is easier to see with larger tires....like installing a 35 12.5 16.5 on a 16.5x7 rim.....but is still there with lower profile small tires.

bnickel said:

actually Nick, i think you're working backwaqrds on this one. with his current combo he would 3.00" inch of wheel sticking out toward the fender, with your combo but you have 3.25" sticking out towrd the wheel correct? so he would have 1/4" more clearance than you have now correct? masybe i'm just lokoing at this wrong, it's late and has been a long day.

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A visual might help here. I apologize for the large images

Here is a side by side of 17x8 and 17x7 on a normallized inch scale with the backspacing lines noted



Here are the same wheels now adjusted for mounting posistion.



And finally here is the wheels adjusted for mounting and skinned with a 245 45 17 which has a section width of 9.6 inches.

Nice graphics, do you think that an 8.5 inch wheel with 4.75 BS would fit with the 245s?

After all, there would be no increase in tread width.

I know that a 225 50/15 fits fine on a 15x7 rim with 4.25" backspacing. Not even remotely close to rubbing.

2bav8 said:

I know that a 225 50/15 fits fine on a 15x7 rim with 4.25" backspacing. Not even remotely close to rubbing.

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Ineresting, but an 8.5 inch wheel with 4.75 BS would have one inch more rim outboard towards the fender lip than the 15 x 7 you mentioned.

Assuming that the wheel width is less than the tread width, my question is this:

Does increasing the wheel width increase the overall width of the tire?

If not, we can run wider rims than the 8s many of us think is the maximum for a 65-66 for example.

I know the overall width is increased if you're comparing a tire that's being squeezed on too small of a rim. But what if you increase the wheel width from say 8 inches to 9 inches on a 245/40/17?