[Tyrolblue67]

Hi,
Looking into switching stock SS wheels and tires to 1LE/ZL1 wheels and tires.
I noticed other than the tire widths, there is a difference in tire diameters.
Would this be an issue swapping the 1LE/ZL1 wheels and tires onto an regular SS?
Besides the different diameters, the front to rear diameter ratios are also different. Would this cause problems with the speedometer and/or computer that handles traction control?

1LE/ZL1..... Front-285/30/20 Diameter 26.7...Rear-305/30/20 Diameter 27.2....Rears are taller by .5


SS....Front-245/40/20 Diameter 27.7...Rear-275/35/20 Diameter 27.6...Fronts are taller by .1

Thanks,
Tyrolblue67

[bpang1234]

Driver's side rear wheel well has this little hump at the front part of it kind of in line with the axle...more or less. Behind that hump is a wire loom that you should probably move since almost all of us have worn that little hump to a hole when going to big rubber.

Not a great design move on GM's part...why make a different wheel well liner for SS vs. the one that the 1LE and ZL1 get? Doesn't make sense.

[EDFHOBBIES]

if you stick with 30 series you will not rub and be fine.

I have 305 35s 20 rear and 285 on front the F1 g2s, were to cheap to pass up. I just moved the harness over.. the 35s really feel the fender gap gives a semi lowered looked by filling up the space.

I have noticed the same thing on my 5th gen and now my 6th gen going wider makes the car follow the grooves in the highway giving the effect that car is harder to keep straight because it wants to follow these grooves on warn pavement. The grooves are not noticeable to the eye except for when it rains you will see the 2 tire channels on the hwy from car traffic where the water pools.

A buddy of mine has stock front size and went 295 on stock rims in the rear and noticed the same thing about the grooves grabbing the tire more..

[cncmotors]

Go with 30 if you consider 20" rims then you can also get 315 tires.
35 is good for 19" rims in ma opinion.

[PK Auto Design]

If you do the 285/30 and 305/30 you will be fine with no issues, if you do a 305/35 you will shine up the inner fender liner on the driver side.

[pavetim]

Old post but will these make the tires stick out and then spit rocks on the car, if you use stock wheels?

[arpad_m]

Originally Posted by pavetim

Old post but will these make the tires stick out and then spit rocks on the car, if you use stock wheels?

I wouldn't do it, especially in the front, 285 width is well beyond what a 8.5" wheel is designed to support.

[ParisTNDude]

I have just gone through an expensive lesson with 285/30/20s on the front. It began throwing the service stabilitrack traction control and brake warning lights after driving about 3 minutes. I had 305/35/20s on the rear. Went back to 245/40/20s on the front and everything is back to normal. I am using 1LE wheels which seem to fit this size tire perfectly. Just sayin'.

I am using the Nitto 555r2s on the rear and Nitto G2s on the front. I initially went with 305/35/20 G2s on the rear, but now with the supercharger, I couldn't give it WOT at anything below 65 mph.

[arpad_m]

Originally Posted by ParisTNDude

I have just gone through an expensive lesson with 285/30/20s on the front. It began throwing the service stabilitrack traction control and brake warning lights after driving about 3 minutes. I had 305/35/20s on the rear. Went back to 245/40/20s on the front and everything is back to normal. I am using 1LE wheels which seem to fit this size tire perfectly. Just sayin'.

I am using the Nitto 555r2s on the rear and Nitto G2s on the front. I initially went with 305/35/20 G2s on the rear, but now with the supercharger, I couldn't give it WOT at anything below 65 mph.

I'll tell you why. Look at these comparisons, you went 2.9% taller in the rear and 3.6% shorter in the front, which is a combined difference of 6.5%, way above the threshold that will trigger stabilitrak and ABS warnings. When you switched the fronts back to OEM, you squeezed the difference back down below the threshold to 2.9%.

I run 275/35/20 in the front and 315/30/20 in the rear on the same 1LE spec wheels, with zero issues. IMO the ideal rear tire size would actually be 325/30/20 (with 285/35/20 fronts) for this setup on a non-1LE SS, but Michelin doesn't make the PS4S in this size, hence my choice.

[DorsoDuroJohn]

This is really solid information to have, thanks for providing. I'm in the market for a new spring setup.