I've searched and found plenty of examples of staggered widths front to rear, but nothing about staggered wheel diameters. I'm old school enough to remember the real "big-'n'-little" look. I realize that the ABS computers aren't going to allow too much difference in roll-out, but if that's controlled, is it OK? What I'm looking at is 19"x10" rears with 285-35R19's (generally about 26.9") and 18"x9" fronts with 245-45R18's (most show about 26.8"). Any reason this wouldn't work?? Potential handling issues, besides more understeer at the extreme, which I'm willing to accept?? Car is a '10 GT currently wearing 235-50R18's.

JW

 

Ha haaaa....

I'm just teasing you, as .2" is not going to be an issue in the slightest. The "general rule" of such a differential causing issues is 1", so no probs at all. I say "general rule", because I have done LOTS of research on this particular subject and could not find a consensus on it. It will also vary per manufacturer of ABS sensors and can be calibrated to address such issues anyway. Just look up a Dodge Prowler, for a good example.

I would suspect that understeer will be an issue, but don't have enough experience with an S197 to say for sure.

Jazzer

 

Thanks Jazzer--that's what I suspected but wasn't sure about. Still noodling around some different ideas, including lowering the car as well. May end up going slightly larger diameter, especially on the rear, to fill out the wells. Maybe use more of that 1" differential.

JW

 

I don't recommend you try to fill the wheel wells via larger diameter tires. Pushing that 1" mark can still cause some ABS issues, just not too bad. This also reduces clearance within fenders, elevates your car and effectively changes the gear ratio a bit.

I recommend you go the same size, or very close, tires all the way around and stick with nearly and OEM 25.6" diameter tire.

Jazzer

EDIT: oops.... 27.3" for the '10 Stangs. Was referring to the SN95, my bad

 

Then slam it!, ok just lower it some.

 

 

At least a 255 tire for those front 9s, 245 would look rather strange.

 

245/45 is fine on 9" wide rims, at least as far as the tire mfrs and the Tire & Rim Association are concerned.

FWIW, Ford put the 255/45-18's on 9.5" wheels up front on the GT500's. Any taller than 245/45-18 and the front tires start being taller overall than the 19" rears mentioned, and the difference in front vs rear sidewall heights would be exaggerated slightly.

45 and lower profile tires are specifically designed to be fit to relatively wider rims than the 55 profile and taller tires. What that means is that the traditional "look" for tall profile tires on their correct rim widths (where the sidewalls bulge over half an inch past the outer edges of the wheel flanges) is something of a "wrong" shape for low profile tires.


The guideline with respect to ABS that I've heard is 3%.


Norm

 

It's fine, but it won't look right.

255/35
or
255/40
or
265/35

 

"Looking right" is a matter of perception and where you're coming from.

Cornering performance and general behavior generally improve as wheel width goes up. So if that's what you're after, and fitting tires to the maximum recommended width gives that to you, then that becomes the "right" look from that perspective. You just have to be sufficiently hardcore to accept it, I guess.


If I was buying wheels to fit that exact range of tire sizes, I'd be looking at 10's. Wouldn't settle for less than 9.5's.



Norm