'12 GS Driver

I'm in the process of buying new tires for my 2012 GS, it has original Goodyears with 17000 miles on them. Front ones still good. My question is, Can I substitute 345's for the 325's and 285's for the 275's? I'm still using stock GS wheels. Will I have any fitment problems? Is there an advantage over stock sizes? I do not track my car and it is just a weekend driver. I am choosing the Michelin PSS's. Thank you in advance.. Sorry for all the (dumb) questions.

Travelor

There are no dumb questions, just dumb answers.

"In the Day", we always used to go up one size when we changed tires from the factory tires. Now with all the computer monitoring going on and the LARGE size of the factory Grand Sport tires, I would stick with the factory sizes. Your speedometer will read correctly and the computer will be happier.

Just my two cents worth, I will be facing this same tire change before long and will go with the Michelin tires also.

ben dover

The circumference needs to stay very close to the same.

NOVAtwinLS3

I went 345 Nitto Invos, on my GS, much better ride than GY's. No problems with them.

MelAnn

Discount Tire has a page that will let you enter the original tire size and the intended tire size. It will show you what changes to expect.

http://www.discounttire.com/dtcs/infoTireMath.dos

'12 GS Driver

Thank you all very much for your answers, formula was very useful,, not much difference between them.. Thanx again..

icntdrv55

Pretty sure there is a specific thread on this forum about switching to those exact tires/sizing and the OP stated he had no issues with with either clearance or the TC nannies. Based on the data from Tire Rack, I get these ratios for your OEM fitment vs your Michelin PSS choice:

OEM GY Eagle F1 Supercar EMT
275/35-18 = 816 revs/mi
325/30-19 = 783 revs/mi
*F:R ratio = 1.042

Michelin PSS (non-RF)
275/35-18 = 814 revs/mi…or...285/35-18 = 804 revs/mi
325/30-19 = 778 revs/mi…or...345/30-19 = 765 revs/mi
*F:R ratio = 1.046…………..or…….F:R ratio = 1.051

*F:R = Front:Rear

Based on that data, your change in revs/mi ratio (F:R) is less than 1.0% (0.9% actual) and altho I do not know what the permissible TC variability is spec'd at, I would seriously doubt that a change of less than 1% would get the E-nannies all riled up.

PittMD1

I don't see anyone saying they would use the Brigstones which is what I was considering. Currently my 2012 GS has 17K but still have a lot of tread left. I would value any input as to why you chose the tire you did.

ButWhatDoIKnow

The larger tires could hurt your acceleration some by changing the rear ratio.

But with the torque and six gears, you won't notice unless you race your car.

5W30

http://forums.corvetteforum.com/c6-c...ed-stance.html

'12 GS Driver

I'm just going with what most of the Forum members are saying..never bought a set of tires for a Vette before,,, had an 04, sold it after 4 years, 12,000 miles on tires, and still looked decent. I have considered the Bridgestones,, but for what I seen most members are using Michelins.

'12 GS Driver

That's another can of worms I'm not ready to tackle yet!!!

Stavesacre21

Considering how monstrously large the Grand Sport tires already are, I don't feel that there really is much of a reason to go a size larger. Just my $0.02

olefam

I am also looking at increasing the tire size for our GS. I don't need more rubber on the road, but for some reason, 345-19s are sometimes less expensive than 325-19s. I was told it is because there are other cars using this larger tire, and so more are being manufactured, and the price is slightly less per tire.
Glen

mww3519

I made this exact change myself last spring on my 2010 GS. I have had absolutely no issues in going with the 285/345 combo with the Michelin PSS tires. Ride and traction are both much improved. The PSS have way less road noise, no tramlining, better ride, and traction is way better. They do feel a bit different than the GY run flats though, not quite as planted, a little "wiggle" to them (best way I can think to describe them). Certainly not bad, just different, I am sure that is the trade off for the softer side wall.