[NotFast]

I can't wait to dump the stock run-flats. I have nothing to compare them too currently, but it seems like my LT1 rides like a truck in the cooler weather.

[6sigma]

Originally Posted by ProdigalLunatic

I love that Rally green. Wish had still been available on the '21s. Looks sharp! I'd like to do the same thing you did, pick up some 1LE wheels. But that may be next year's project. I'm jealous.

Thanks! It is my favorite color of the 45+ cars I've owned so far. And I prefer lighter colors generally, but there is something about the dark green on this car that looks just right. In bright sun and when clean it really shows the metallic green. Was really disappointed they canceled it.

[TenTwo]

Originally Posted by arpad_m

Aren't your wheels 8.5" all around? If yes, 275 will to be too wide, using softer sidewall tires such as the PS4S will probably result in sloppy steering response, plus they'll look bad, too. Not saying a square setup can't be good, but AFAIK it's typically chosen for cost savings through front-to-back tire rotation.

Here's a (slightly conservative, but still practical) wheel/tire sizing guide:

Wheel and Tire Widths
Rim     Min        Ideal       Max
5.0     155     165 or 175     185
5.5     165     175 or 185     195
6.0     175     185 or 195     205
6.5     185     195 or 205     215
7.0     195     205 or 215     225
7.5     205     215 or 225     235
8.0     215     225 or 235     245
8.5     225     235 or 245     255
9.0     235     245 or 255     265
9.5     245     255 or 265     275
10.0    255     265 or 275     285
10.5    265     275 or 285     295
11.0    275     285 or 295     305
11.5    285     295 or 305     315
12.0    295     305 or 315     325
12.5    305     315 or 325     335

Late response, but the search function brought me here. Just wanted to say thank you for sharing this info.

[ilovemusclecar]

Originally Posted by seethruya

Your only option is purchasing aftermarket rims (20x11 in the rear) and going at least 295-305 in the rear. The stock 245s are one of the better all seasons but they’re not performance tires. They’re fine if you never push your car but if you do, they’re hopeless. In everyday driving, I could inadvertently spin the tires with a half throttle acceleration.

All the stock rims available with the LT1 are worthless if you’re looking for performance as they’re all 20x8.5. The widest tire you can fit on 20x8.5 rim are 255’s. 255’s are simply not enough tire for 455 ft/lb’s of torque, regardless if they’re performance or not.

Do you think 255s instead of 245s are enough of an increase? I just got my car tuned and it is ripping the tires loose in second and part of third, 6MT. I don't have space to buy new wheels. If I could safely fit 265s on there that may be good enough.

I think the tune is probably going to gain me 40 WHP, but it feels like a lot more. The car is pulling like a freight train compared to stock. I never ran into traction issues on stock tune but now it is every time I go full throttle. If I gained 40 HP / 10% then +10 mm tire size / 5% doesn't sound like enough.. so far I have just been being careful and haven't crashed yet but I am concerned.

Edit: I could also get quality summer tires like PS4S instead of the factory runflats. That + 10mm may be enough.

[Gen6cyl]

Get summer tires 245-40-20. Proper fit with a proper tire will make a difference. You might still be able to get Bridgestone potenza sport on tire rack for half price about $150 each. I have bought 2 sets of them over the last 2 years.

[ilovemusclecar]

Originally Posted by Gen6cyl

Get summer tires 245-40-20. Proper fit with a proper tire will make a difference. You might still be able to get Bridgestone potenza sport on tire rack for half price about $150 each. I have bought 2 sets of them over the last 2 years.

Thanks!

Do you think that setup can hold 440~ RWHP?

[Gen6cyl]

For a 20-8.5 wheel probably best your gonna get.

[arpad_m]

Originally Posted by ilovemusclecar

Thanks!

Do you think that setup can hold 440~ RWHP?

You can 100% safely go up to 255/40/20 all around, and if you don't mind the stretched look, even to 265/40/20, which I don't recommend personally, but it would work, technically speaking. The size change won't make as much a difference as the compound, though.

Unfortunately the Nitto 555RII only comes in 275 and above widths, so you can't reach for that if you stick with your wheels, but a better tire such as the PS4S or the Conti ExtremeContact Sport 02 will give you tangibly better overall performance. They aren't cheap, but in these smaller sizes you can get them for $280-$300 a corner, much less than what ZL1 folks need to plop down.

[Chutzpah]

Originally Posted by ilovemusclecar

Do you think 255s instead of 245s are enough of an increase? I just got my car tuned and it is ripping the tires loose in second and part of third, 6MT. I don't have space to buy new wheels. If I could safely fit 265s on there that may be good enough.

I think the tune is probably going to gain me 40 WHP, but it feels like a lot more. The car is pulling like a freight train compared to stock. I never ran into traction issues on stock tune but now it is every time I go full throttle. If I gained 40 HP / 10% then +10 mm tire size / 5% doesn't sound like enough.. so far I have just been being careful and haven't crashed yet but I am concerned.

Edit: I could also get quality summer tires like PS4S instead of the factory runflats. That + 10mm may be enough.

I have the stock tune w/1LE wheels and tires. At ~ 65-70F the car still steps out under moderate to hard acceleration (from a stop, pulling into traffic). Crashing shouldn’t a concern, let off the gas and the it’ll straighten right out.