305 Tires on 2011 GT500 with SVT Track Pack

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03-07-2011, 05:59 PM

#11

quorum

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Join Date: May 2010

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Quote:

Originally Posted by Kotobuki

A 305/30-20 would be about 3/4" shorter overall (about 3/8" shorter sidewall), compared to stock. A 305/35-20 would be about 1/2" taller overall (1/4" extra sidewall) compared to stock. I don't know what the front tires are like, so the 305/30 might be okay, so long as you don't end up smaller than the front. The 305/35 would probably be the better choice, especially if the 10" with the minimum size for a 305 section width.

Obviously, all these numbers are just rough averages, and will vary from manufacturer to manufacturer, but they'll be close.

thanks - will changing the rear wheel height affect the speedometer/odometer?

thanks!

03-08-2011, 11:59 AM

#12

Norm Peterson

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Quote:

Originally Posted by quorum

thanks - will changing the rear wheel height affect the speedometer/odometer?

Yes.

But in most cases, being plus or minus half an inch on the tire diameter away from the OE tire dimension isn't worth worrying about. Think about it - there's about half an inch of total tread depth that wears off the diameter from brand-new to replacement time and nobody ever worries about that effect.

Norm

03-09-2011, 12:58 PM

#13

quorum

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Thanks - what about a 315/35R20 tire?

According to a wheel height calculator, that will add 21mm height to the rear, or 0.84" extra diameter.

How will this affect:
1) the appearance of the car? Will it look too tall in the rear?
2) dynamics/handling?

What do you guys think of adding a 315/35R20 tire? Apparently a 10" wide rim can fit a 315 tire quite comfortably. Would you do it? Would it fit well in the wheel well?

Thanks!

Last edited by quorum; 03-09-2011 at 01:11 PM.

03-09-2011, 02:10 PM

#14

Norm Peterson

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Quote:

Originally Posted by quorum

Apparently a 10" wide rim can fit a 315 tire quite comfortably.

Not according to the people who actually make the tires. 10.5" is the recommended minimum width wheel for that size. I checked several.

While that doesn't make 315/35's on 10" wheels an immediate 'fail', you are somewhat more likely to encounter unusual tread wear patterns and you would be giving up some of the margin of safety against things like sidewall heat buildup. Can't really visualize what the car might look like with them, and I wouldn't myself ever buy tires just for the appearance factor anyway. So I'll stay out of that part.

Personally, I wouldn't run any tire on below-minimum-recommended wheels in normal street driving unless I found myself in a situation where I had no other choice.

Norm

Last edited by Norm Peterson; 03-09-2011 at 02:13 PM.

03-10-2011, 10:26 AM

#15

quorum

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Thanks everyone for all the advice.

So if I were to add an 11" wheel to the rear, would I get a wheel with the same offset as the SVT PP 20" rear wheel? What is the offset?

And - can an 11" wheel be added without any other modifications to the wheel well?

What about a 12" wheel? Nitto says you need a 12" for one of their 335 tires. Can a 12" with a 335 tire fit?

Thanks!!!

Last edited by quorum; 03-10-2011 at 11:00 AM.

03-17-2011, 01:18 PM

#16

RacinRandy

Join Date: Jul 2010

Location: Texas

Posts: 11

305's on SVT-PP

Thinking about getting some drag radials for my 2011 GT500 SVT-PP.

285/35/20 don't seem to be available anywhere.

305/35/20 in Nitto 555R's are out there.
Anyone put these on stock wheels and tried them?