285/35/20--it wont work?

After browsing around I came to the conclusive decision on the wheels I wanted to go with. The dimensions being:

Front: 20x9 30mm Offset (I believe, have to confirm)
Rear: 20x10.5 45mm Offset

I added tires to the order, although they weren't my favorite options, I chose a less expensive option for this initial purchase which led the dimensions to be:

Front: 255/35/20
Rear: 285/35/20

Well, after placing the order I got a call stating that the rear wheels won't be available till mid-December—which I knew— but then, the specialist said they are seeing the rear tire setup is too tall for the vehicle.

Prior to ordering I saw some similar setups with no issues and when selecting the wheel/tire combination from the website.....it was one of the recommended tire options.

Am I not noticing something here?

I am by no way a wheel/tire expert and I thought I was using all the tire/wheel fitment calculators properly. Any assistance or direction is appreciated!

Vehicle currently does not have any suspension work (springs/coilovers) but look to follow-up with something to lower it a bit with the wheels.

The rear tire size is a hair taller than stock, by just under 5/8". I don't think you would be able to see the difference at first glance, and the speedometer difference will be negligible.

And your wheel offset and tire width are spot on.

if they are 5/8" taller, as stated, you're fine.

My tires are 3/4" taller than stock, it's all good.

What's the stock tire size on your GT?
I've run 305/35/20 on 20x10 wheels with 48mm offset, with no issues.
285/35/20 on those 20x10.5 will fit great, although the 45mm offset will be pretty aggressive, pushing the outside of the tire/wheel pretty flush with the fender, maybe even outside it a bit.

46addict said:

The rear tire size is a hair taller than stock, by just under 5/8". I don't think you would be able to see the difference at first glance, and the speedometer difference will be negligible.

And your wheel offset and tire width are spot on.

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Thanks for the feedback! I didn't think the difference was anything substantial.

stkjock said:

if they are 5/8" taller, as stated, you're fine.

My tires are 3/4" taller than stock, it's all good.

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Excellent, thank you for your help!

Gabe said:

What's the stock tire size on your GT?
I've run 305/35/20 on 20x10 wheels with 48mm offset, with no issues.
285/35/20 on those 20x10.5 will fit great, although the 45mm offset will be pretty aggressive, pushing the outside of the tire/wheel pretty flush with the fender, maybe even outside it a bit.

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Stock size is 235/50/18 which is on the stock 5-spoke design wheel. Flush is fine, outside....not so much. Guess we shall see.

OK, so your stock tires are 27.25" tall, the 285/35/20's are 27.85" talk, they'll definitely work.
I just wish the 10.5"-wide rear wheels available for our cars had offsets more like 50-55mm so we could more easily run 305/35/20's without the tire hitting the fender.

Gabe said:

OK, so your stock tires are 27.25" tall, the 285/35/20's are 27.85" talk, they'll definitely work.
I just wish the 10.5"-wide rear wheels available for our cars had offsets more like 50-55mm so we could more easily run 305/35/20's without the tire hitting the fender.

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Agreed. The next go around I hope to squeeze a little bit wider of a tire for the fronts and rears but once I have them on I will have a better idea on clearance.

I run a 305/45/17 DR on a 17x9.5 Darkstar wheel and have ZERO rubbing issues. The wheel measures 27.81 in height is 12.01" wide making it .04 shorter than your tire and over .75" wider. I drive the car to the track on the tire/wheel rear combo. So unless you are running some "JOE DIRT" lost in the west coast mid 80's, mini-truck skated wheel offset that makes the wheel stick out from under the wheel well, you should be good to go.

285/35R20 was also a rear factory size on the last of the GT-500s ... so no problem to fit that on an S197 as long as the wheel offset is close.

BTW 245-40-20's will be a great match for the front. only about .15" difference in height. Or 245-45-19 if you choose to run a 20R 19F setup. I found matching tires in both sizes along with the 285-35-20 in the Firestone FireHawk Indy 500 tore. Good looking wheel and great price. Been getting great reviews as well.