Thompyt

Looking to buy new tires for 08 LT2 (18x8.5) & (19x10). Stock is 245/40-18 (25.7) Rear is 285/35-19 (26.9). Wanting to put on 255/40-18 (25.9) and 305/30-19 (26.2). Wheel height difference is Fr (.2), Rr (.7). Will this screw with traction control with a rear to front difference of 1/2 inch? Rather have more sidewall for the rear though. Any suggestions on "affordable" tires for a DD?

MARSC6

Check out http://www.tirerack.com/index_w.jsp

There are many tire options in the correct sizes.

JoesC5

The rears on my Z06 are 4.3% larger then the fronts. I believe that it is about 4.7% for the base C6. I would shoot for that same % with larger tires.

Thompyt

Understood and have checked the website previously. I was looking at the Nitto Invos with the larger sizes for my new rims. I was wondering about other options in those sizes and the discrepancy of the ratio between OEM tire height and the stated size wanted.

MARSC6

If your playing with sizes this might help http://1010tires.com/TireSizeCalculator.asp

Thompyt

I took 4.5% median and applied to tire heigth. OEM comes out almost exat with front vs rear. Sor a 305 I need to find a 305/35 or 27" rear tire to keep 255.

Thompyt

Thanks, that helped the process a lot. I've got it now. 255/35-18 and 305/30-19 gives the 4.5% ratio. Found some additional tire brands in my price range.

m R g S r

275/35/18 and 295/35/18 on my base coupe and no TC problems.

deecount

I remember reading a thread where this was discussed -

http://forums.corvetteforum.com/c6-f...d-upfront.html

Powerlabs (post #15) made mention that the BCM requires no more than +/- 3% size difference in diameter to the factory sizes.

C6Vette1

Did you decide to go with the 255/35/18 and 295/30/19 on the stock rims? How do they work in autoX and HPDE's?

taken19

275/35/18 and 305/30/19 on stock rims here. Thats about 0.7" difference in diamater. Only run into computer issues on the road course above 90 mph.

265/35/18 and 305/30/19 has proven to work just fine on the street and the track. This maintains anout 1.0" diameter difference.

If the computer sees anything much different than the expected 1.1-1.2" diameter difference, you could have issues at higher speeds.

haljensen

Diameter is just one consideration for a tire size change.

The 245mm front tire on a 8.5" wide wheel is correct, a 275mm tire on a 8.5" is not correct.

The 285MM rear tire on a 10.0" wheel is correct, the 305mm tire on a 10.0" wheel is not correct.

You are losing sidewall support and affecting handling by going a wider tire on a narrow wheel.

C6Vette1

What HPDE tracks have you run with this combination? Have you run the same tracks with the stock 245 and 285's? Are your lap times, and overall feel and control as good with the 255 and 295's?

taken19

I have only run Homestead Motor Speedway. The 275/305 PS2 combo is running 6-7 sec faster than my 245/285 Wide Oval runflats. Now some of that is tread rating, but I don't believe it's all of it.

In addition, you can definately feel sidewall flex in the 275-305's but again, that could be the fact that they are not runflats (much thicker sidewall). Haven't run 255's or 295's yet, but plan on swapping to 265/305 for my next set of tires.

C6Vette1

6-7 secs sounds like a huge difference. What factors are leading you to consider 265's for the front next time?

taken19

265/305 should allow for TC on or Comp mode on the track. No other reason.

C6Vette1

Do you use these tires in regular street driving too? Do the lower profiles give a much harsher ride?

taken19

Yes some street driving. No significant difference in ride harshness, at least not enough for the wife or I to notice.

Neumonic2002

Good info here...helping as my rear tires will need to be replaced in the next 1-2 months. Replacing the stock sized Invo's with something a little wider is exactly what I would like to do but my front tires probably have another 10k left in them..