Tire size for 18x8 (or 19x8)?

[CSiJason]

I've been pondering doing a set of 18x8 or 19x8 wheels from an australian maker called XHP Alloy Wheels. The "Saber" as they call it is available in a number of finishes, one being a machined face with gunmetal accents on the sides of the spokes and in the lug areas plus a polished outer lip. Basicly, the exact finish I would want on a wheel. :hail:

Anyhow, I've calculated that if I go with a 245x40 18" tire up front (or 245x35 19") I get the same rolling diameter as stock. But with that I would want to mate it to a wider rear for a little extra meat. In which case, a 275x35 18" (or 275x30 19") would be the closest match, roughly 0.1" shorter than the front.

The catch here is, will a 275x35 mount on an 8" wheel without problems, or will that be an issue? These wheels have a 42mm offset if I remember correctly. Will that in itself be an issue with such a wide rear tire? (with or without rolling the fender lip)

The OTHER option is to go with a 235x40 18" front (or 235x35 19") and a 265x35 18" (or 265x30 19") on the rear which should mount on an 8" wide wheel just fine. This would be a comperable rolling diameter from front to rear but slightly different than stock so the speedo might be off slightly. The drawback here is, these are both very hard to find sizes compared to 245's and 275's.

I remember seeing someone that had mounted 275's on the rear of stock 17x8 GTO wheels and had no problems to speak of, but wondered really what the drawback is going that wide on a narrower wheel and if it was a danger in any way? The simple fact is, I might have to go with the 235's and 265's like it or not, but that'd really limit tire options.

The wheels in 19x8: :eek2:

http://www.ls1gto.com/forums/attachment.php?attach mentid=5189&stc=1

[CSiJason]

Edit: It seems their are a number of 18" tires in all the above sizes for a reasonable price but 19" tires in 235 and 265 are sparce while 245 and 275 are more common though pricey. I'm most likely going with 18's anyhow, but wouldnt mind running 275's out back with 245's up front just to keep things roughly the same as stock. (rolling diameter that is)

I'll likely run Nitto 555's (non-drag) all the way around in whatever I get.

[cosmosmatt]

Dude, that looks badass!!!!! So what was the final word? we know 19x8, what size tire, offset, bolt pattern? Did you have to roll the fender at all? Does it rub?
I gotsta get me some of those bad boys! One more thing how much $$ and what brand are they? Where did you get them? Sorry so many questions but I need all details.

[Chrisbequick]

That isn't Jason's car. he's waiting for an '05.

-Chris

[CSiJason]

That isn't Jason's car. he's waiting for an '05.

-Chris

LOL, Chris really is quick... Beat me to the reply!

That is a Holden HSV GTO. I do believe those are 245x35's all the way around. According to the wheel maker and one of their major retailers (who I plan on purchasing these from), the wheels are designed to fit Holden vehicles specificly. They said 265's will fit fine on the rear without rolling fenders with these wheels. (How that applies to the American GTO has yet to be seen.)

I HOPE to squeeze 245's up front and 275's in the rear which should look nice and give plenty of traction. Though i may end up with 235/265's depending on feedback here about the tire size on an 8" wheel.

[MLTTASK]

If this car is set up to have the same traction on all 4 corners, you may really screw up the handling balance with bigger tires at the rear.

If you put larger tires at the rear, you'll have to keep that in mind for all of your other suspension mods. You'll always want to go with frimer shock settings and heavier roll bars in the rear to keep your car from being an understeering pig.

Of course, if you don't ever plan to track your car, this may not be an issue.

[CSiJason]

I was probably going to bump the rear sway bar up to the next beefier one over stock to help compensate for understeer. Becides, i'd never auto-x or race the car on a track but I do love to drive on the street within reason.