cstich08

I'm looking into getting new wheels and tires. To keep the handling balanced I need to have the same size tires all the way around. In the front I would like to go with 9" wheels for clearance reasons and in the back I would like to get the 10" wheels for the deep dish look. Is it possible to run 275 tires all the way around with 9" wheels in the front and 10" in the back? what would be the problems with a setup like this? I realize that there is a good chance that this is an idiotic idea so I figured I'd ask

Sleeper_08

If you go to Tire Rack you can find charts which show for each size what the recommended rim widths are for all of thier sizes. Here is an example for BFG KDW2s

http://www.tirerack.com/tires/Spec.j...irePageLocQty=

1BADHRSE

I have been told over and over to not use 275s in the front that they will rub...

Philostang

Who do you talk to? Might want to check your company. Then again, perhaps the more important question is, "who do you listen to?"

275's in front will rub if you use the wrong offset. They won't rub if you use the correct offset for your wheel (and don't drop the car more than 1.5"...which if you care about handling you won't be doing on the S197 anyway). This has been hashed over fairly well, so some basic research is in order.

To the OP's question, I'd reserve final judgment until some more knowledgeable folks chime in, but I don't see any serious problem with your proposal. Your handling balance won't be perfectly preserved, since you're making the 275s up front work harder with a wheel that is less well suited to their width (assuming the same aspect ratio). In simple terms, they'll "flex on the wheel" under hard cornering more than the ones nicely supported by the 10" wheels in back. How much of an impact this will be I can't honestly say, so though in theory this effect should be there, you may not even feel it.

One thing I wonder about is why you think you need to run a 9" wheel up front? Roush has 18x10" (+45mm offset) that they shod with 275/40R18s running on all four corners. You can, of course, very easily go with 18x9.5" from +35mm to +45mm offset wearing the same tires on all four corners. So why the split?

Best,
-j

howarmat

275 fits, comes stock on a few cars. they might rub a little, i know 285s do if you turn the wheel all the way

zero2sixd

My $.02: just use 18x9.5 +45 offset with 275s on all four corners. There are no rubbing issues with this combination and Eibach Pro-kit or Steeda Sport springs (I've used both).

At least this would let you rotate tires. You should consider carefully whether the tire is directional as well. If you choose directional tires you'll not be able to rotate tires at all with the staggered wheel sizes.

cstich08

Philostang, I want to run 9" up front for appearance reasons. I am looking into getting the Fr500 replicas and i want to have non deep dish in the front which only comes in 9" and I want deep dish in the back which only comes in 10"

if someone can confirm or disprove philostang's potential problems it would be much appreciated.

the tires I am looking at would be 275/40/18 on all 4 wheels. the offset on the front is +30 and +40 on the back. if that helps anything

Norm Peterson

The outer flange on an 18 x 9 x 30mm will sit 0.34" further out than the outer flange on an 18 x 9.5 x 45mm.

Maybe somebody with 275/40's on 18 x 9.5s can comment whether there's still room for the tire being about 3/8" more to the outside.


Norm

Philostang

This isn't exactly what you asked for Norm, but here's a shot of an 18x9.5" wheel with +35mm offset carrying 275/35/40 tires. The front is dropped 1" from stock, and I've got about -2 deg. camber.



If you look real close you can see the string I hung from the fender. IIR there's a smidge over 1/8" clearance to the tire and a bit more to the wheel. Obviously, if this were a +45mm offset wheel, you'd have plenty more clearance. So the short answer is there's room.

Also, I'm running an 18x9" wheel as a street set-up, and they have +30mm offset. By the eye, you can hardly tell the difference between the fender clearance of the two sets. No pics now, but I can get some later if there's interest.

One more thing, Norm in my first post here when I said I would reserve judgment until I heard from more knowledgeable folks, I had you in mind (actually, when I say "more knowledgeable folks" it's usually code for "Norm"). Would you grace us once again on your input into how the same tire is going to react on different rims (esp. with regard to handling balance)?

Best,
-j

Norm Peterson

Best guess . . .

I'm thinking that on a 9" wide rim, a 275/40 will have minutely less cornering stiffness (turn-in response that's not quite as sharp or abrupt, and tiny bit more understeer if we're talking about the front tires/wheels) and slightly more gradual breakaway then if they're on 9.5".

All minor effects that you might not notice in reasonably sane street driving even if driven back to back with the same tires in the same state of wear on the two different size wheels.


Norm