[taylorforschool@gmail.com]

Hey everybody, first of all, I absolutely love this platform, and Community. Everybody is extremely knowledgeable about my newest and strongest passion which is my 2020 LT1. I have used you guys for a lot of advice for my car so far (purchased October 2020 with 12k miles built in June 2020.) I know I have my wonders about how previous owner put that on in 3-4 months but nonetheless, getting sidetracked. I have been running the stock 245/20 run flat tires up front with 265/35/20 Ps4S out back (tire discounters claimed that was about widest I could safely out on 8.5 rim or I would of out the 295 I purchased on it. So I absolutely love this tire out back, and have pretty much zero complaints on the run flats up front... the only thing I didn’t like about the 265 PS4S was the tiniest wiggle off the hit, not even a traction light just a little wiggle but otherwise it hooked and gripped 1000x better than the runflats did in the rear. Fast forward 6 months and I’m slowly creeping my upgrades towards boosting when the warranty is gone, but I’ve managed to stay in warranty with my mods for Now.. so I went ahead and got some AR932 20x10.5 for the rear so o could put something wider than a 265 in the back and see if it would hoook without a wiggle. So after moving my PS4S TO THE FRONT, and putting some conti extreme sport 305/30/20s on the AR932s.. the car does hook like I want. However now, when pushing the car in the canyons instead of feeling like I’m driving a Porsche, it feels almost like the car is floating back and forth at high speeds... 75+mph in turns not too sharp.. and also the front PS4S actually starts to lose traction/and or turn traction control on and feels like it’s ABSing just the front wheel under load. I’m ASSUMING this is just because the TC is more touchy with the summer tires out front... and maybe I should put the 245 runflats back up front for better cornering? I never really had a problem with the runflats except the PS4S is a better ride up front and I THOUGHT would of meant better cornering/grip instead of the odd FRONT traction loss I’m now getting in turns with new setup. Sorry guys if this is all silly to most.. I am new to sports cars and younger at 25, so I still have a LOT to learn about this amazing community and passion! Thanks all!

[enzia35]

I've read that more than 1" of difference in tire height will throw off traction control. The 265/35 and 305/35 are at about an inch of difference already, and 6 months of driving may have worn down the PS4S down so that difference may be even more than an inch now.

edit: I see you have the 305/30 so that throws my idea in the trash.

[Joshinator99]

I’m confused, what are you running for wheels in the front?

[enzia35]

Originally Posted by Joshinator99

I’m confused, what are you running for wheels in the front?

I think he threw the PS4S that were on his stock 8.5" tires up front after buying just two new wheels for the rear.

[taylorforschool@gmail.com]

That is correct. Yeah with the 30 series they are damn near the same size height of tire. I’m wondering if maybe I’m also just discovering new limits without realizing because I rarely ever looked at speedo anyways. Just a new phenomena to be losing traction and it causing TC to kick in during a turn on the FRONT. I’m guessing if I wanna drive like that in the future under safe conditions I would need to turn my nannies off and give it a shot.

[Joshinator99]

Originally Posted by enzia35

I think he threw the PS4S that were on his stock 8.5" tires up front after buying just two new wheels for the rear.

Originally Posted by taylorforschool@gmail.com

That is correct. Yeah with the 30 series they are damn near the same size height of tire. I’m wondering if maybe I’m also just discovering new limits without realizing because I rarely ever looked at speedo anyways. Just a new phenomena to be losing traction and it causing TC to kick in during a turn on the FRONT. I’m guessing if I wanna drive like that in the future under safe conditions I would need to turn my nannies off and give it a shot.

Ok, in that case that tire is too wide for that front 8.5” wheel. Michelin recommends a 9.00-10.5” wheel and did their testing using a 9.5” wheel for that size. I suspect your tire is bulging just a tick on that current wheel. Probably fine in a straight line but will perform poorly in the turns. I’d suggest a little wider front wheel IMO. Just my 2 cents.

[taylorforschool@gmail.com]

Thanks josh. The 20x9 for the front I have, is currently on back order. Thanks Camaro fam

[Norm Peterson]

Originally Posted by taylorforschool@gmail.com

Thanks josh. The 20x9 for the front I have, is currently on back order. Thanks Camaro fam

Even 9" will probably behave a bit on the 'soft/vague' side, as that's only the bare recommended minimum per tire industry standards.

"Measuring width" for 265/35 is 9.5", and even that leaves some steering 'crispness' and precision on the table if you're sensitive enough to such things.



Norm

[NA18CamaroSS]

I am no expert, but the stock 1LE tire configuration is pretty good. Since you are running the 305/30/20's on the rear, maybe match it up with 285/30/20's on the front. A lot of guys are running the stock 1LE tires on the track and tearing it up.
This guy has posted a few in car videos from the track : https://www.camaro6.com/forums/member.php?u=157757
And this guy with a 1LE has a Youtube channel : https://www.youtube.com/channel/UCnk...UXE04sxJTSSCyA

[Joshinator99]

Originally Posted by Norm Peterson

Even 9" will probably behave a bit on the 'soft/vague' side, as that's only the bare recommended minimum per tire industry standards.

"Measuring width" for 265/35 is 9.5", and even that leaves some steering 'crispness' and precision on the table if you're sensitive enough to such things.



Norm

[LT4Greg]

You can run a 295/35 20 on the rear if your wheels are 10 inch width. When I put tires on my 2016 SS I used the stock sizes on the front and 285/35s on the rear 9.5 stock wheels. TireSize.com is a good website to use when you are considering changing tire sizes and wheels as compared to the stock sizes.

[Mark114]

Since you bought car used I suggest that you have the alignment checked to make sure there isn’t an underlying problem with the suspension that is causing the vague driving feel. I would also check the air pressure in the tires just to make sure it’s correct. Mixing Michelin and Continental tires front and rear probably isn’t terrible but it could be a contributing factor. I don’t think I would change it now but you might have been happier with matching PS4S 305/30/20s on the rear.

[taylorforschool@gmail.com]

I know I would of been happier, I was getting a better deal and the PS4S are hard to find and so expensive. Thanks for all the tips. I really will probably just get a slightly smaller width for up front. What is the best recommended dimensions for a 20x9 up front? Maybe a 245/255? What’s a good series? I’m trying to save a buck when I can here, so keep that in mind, this is why I didn’t just initially buy ZL1 or 1LE wheels.. just so expensive.

[taylorforschool@gmail.com]

Also I think some folks may think my stock wheels are larger than they are, to clarify, my 2020 LT1 came with 20x8.5 with 245 run-flats all around. Ridiculous but understandable seeing as LT1 is their cheapo v8. I really want to keep the 20x10.5 wheels out back and I would prefer to match the wheels up front with the 20x9. It isn’t a horrible feel even at speeds, and since the LT1 isn’t much of a track machine anyways without the cooling... I just want a tire that will behave the way it should up front in any conditions and still give me ideal maximum performance. I may just get another Conti Extreme Sport when I get the new 20x9 front I just want to make sure I get the right tire for that front wheel moving forward. To be clear I think I like the PS4S better overall, just trying to save a dollar.