[CC2018SS1LE]

Hi Guys, i heard so many guys say that going to a square set up, makes the car handle neutral. So I decided to try it at Sebring, what a difference. Here is my video POV on this set up

[N Camarolina]

Thanks for making this video and giving your opinions on the benefits of square set up. I'm currently running a square Apex set up on the street so I can rotate the tires, but switch back to the 1LE OEM wheels/tires for the track. Are you running 10.5 width rims?

BTW, if you want to calculate your revised speedo with your new vs old tire size, check out this web app: https://tiresize.com/speedometer-calibration/

Assuming the app is correct, you'll see that the speedo error difference is actually larger than the 1-2 mph difference than you thought, especially at higher speeds (so the speed advantage through the corners and onto the straights with the new wheel set up is not as large as you were thinking). But the car is still legitimately a couple of mph faster, and if you like the neutral balance better, then that's all that matters.

I'm less experienced in my HPDE life than you, so am currently fine with the mild understeer balance. I can practice trail braking and purposely increase yaw rate without running the risk of oversteer, at least most of the time.

Please report back after you've had a chance to do some more track sessions.

[CC2018SS1LE]

Originally Posted by N Camarolina

Thanks for making this video and giving your opinions on the benefits of square set up. I'm currently running a square Apex set up on the street so I can rotate the tires, but switch back to the 1LE OEM wheels/tires for the track. Are you running 10.5 width rims?

BTW, if you want to calculate your revised speedo with your new vs old tire size, check out this web app: https://tiresize.com/speedometer-calibration/

Assuming the app is correct, you'll see that the speedo error difference is actually larger than the 1-2 mph difference than you thought, especially at higher speeds (so the speed advantage through the corners and onto the straights with the new wheel set up is not as large as you were thinking). But the car is still legitimately a couple of mph faster, and if you like the neutral balance better, then that's all that matters.


I'm less experienced in my HPDE life than you, so am currently fine with the mild understeer balance. I can practice trail braking and purposely increase yaw rate without running the risk of oversteer, at least most of the time.

Please report back after you've had a chance to do some more track sessions.

Hey thx for that mph calculator, if it’s accurate there is a 3.5mph difference at 100mph. So if the calculator is correct, I am still several mph faster, then with OEM diameter tires.
I run 11in rims all around. I definitely feel a huge difference in the car, I think I will get faster, as I get used to not understeering. No to mention my toe moving, due to a bad alignment shop in boca called autobahn, stay away. I will definitely post as I do more track days. Thx for you input

[N Camarolina]

Your welcome.

The other thing that would be great to hear more about is your experience with how the PTM traction control behaves on corner exits with the new sqaure setup, given that it was calibrated against a stagger setup with more relative rear end grip.

I choose not to mash the pedal on corner exit as PTM would theoretically allow, and instead roll onto it while trying to stay just below the threshold of traction control activation. So with my approach, it might not make a difference if I went to a square setup. But I could see how it might, if instead you use PTM Sport 2 or Race and had gotten used to mashing the pedal on corner exits with the staggered wheel setup.

[CC2018SS1LE]

Originally Posted by N Camarolina

Your welcome.

The other thing that would be great to hear more about is your experience with how the PTM traction control behaves on corner exits with the new sqaure setup, given that it was calibrated against a stagger setup with more relative rear end grip.

I choose not to mash the pedal on corner exit as PTM would theoretically allow, and instead roll onto it while trying to stay just below the threshold of traction control activation. So with my approach, it might not make a difference if I went to a square setup. But I could see how it might, if instead you use PTM Sport 2 or Race and had gotten used to mashing the pedal on corner exits with the staggered wheel setup.

Another good point , whenever I test a new setup I use the nanos (sport 2), just as a backup, if there are any handling surprises. As you can see in the videos I can mash the throttle with this set up, the PTM was not affected by the smaller diameter wheels.
This square setup is so good, I will be in race mode next time I take it out

[Christian1LE]

Why did you decide to go with different wheels in the front and back instead of a true square setup? Doesn't your setup still only allow you to change tires from left/right.

Wouldn't it make more sense to go with the Front & Rear @ 19x11" ET35, using 26mm spacers in the front?

[CC2018SS1LE]

Originally Posted by Christian1LE

Why did you decide to go with different wheels in the front and back instead of a true square setup? Doesn't your setup still only allow you to change tires from left/right.

Wouldn't it make more sense to go with the Front & Rear @ 19x11" ET35, using 26mm spacers in the front?

Hi it’s a square set up diameter wise. I have no need to swap front to back. I did not want to put on extended wheel studs, I want to keep it looking stock. All I did was make the car go faster.

[carguy55]

Been running 305 true square for 4 years with 10.5x19 ET22 Apex wheels. Works great on SS 1LE

[Christian1LE]

Originally Posted by CC2018SS1LE

Hi it’s a square set up diameter wise. I have no need to swap front to back. I did not want to put on extended wheel studs, I want to keep it looking stock. All I did was make the car go faster.

I see, I am going to get a square setup soon. I feel like allowing front/back rotation will get me at least 1 maybe 2 days extra out of the tires. As of right now when my fronts are down to the cords the rears still have a good amount of life left in them.

[CC2018SS1LE]

Originally Posted by Christian1LE

I see, I am going to get a square setup soon. I feel like allowing front/back rotation will get me at least 1 maybe 2 days extra out of the tires. As of right now when my fronts are down to the cords the rears still have a good amount of life left in them.

Understand, but I can just have a shop, swap tires, if in need. So it’s not that big of a deal, for me. Thx for input

[DaveC113]

I've got a set of Anthracite Apex SM-10 19x11 et 35, 26mm spacers and longer wheel studs that will be going up for sale soon. Studs do not require removing the front hubs to install, just take off the brakes.

I'm going back to staggered for AX use, less likely to see ice mode.

[VR Baron]

Originally Posted by DaveC113

I've got a set of Anthracite Apex SM-10 19x11 et 35, 26mm spacers and longer wheel studs that will be going up for sale soon. Studs do not require removing the front hubs to install, just take off the brakes.

I'm going back to staggered for AX use, less likely to see ice mode.

I will add as others have said on lack of ice mode, my 21 doesn’t have it. Even with square re71s. On a low grip autocross surface.

Another bit of info, if it helps anyone, my 19x10.75 cheapy wheels I can’t rotate as offsets are 15 and 35, but not my street set and only autocross. Wear is only 1/64-1/32 more on the front then back. Probably as I run32/28 psi split for best rear grip and getting close to same fro t rear tire temps. Best as I can tell anyway.

[DaveC113]

Originally Posted by VR Baron

I will add as others have said on lack of ice mode, my 21 doesn’t have it. Even with square re71s. On a low grip autocross surface.

Another bit of info, if it helps anyone, my 19x10.75 cheapy wheels I can’t rotate as offsets are 15 and 35, but not my street set and only autocross. Wear is only 1/64-1/32 more on the front then back. Probably as I run32/28 psi split for best rear grip and getting close to same fro t rear tire temps. Best as I can tell anyway.

The '19+ cars do have ice mode, but it's less likely to activate during track use vs previous models. M Squared says his '20 gets it a couple times a season. The GM engineer on the AX thread says '19+ is more robust for use with different tire setups, but he does not say there's no ice mode at all. I got a '19 ABS module from ebay on the way, that will help a lot, but it's well known that a staggered setup reduces the likelihood of ice mode too. After experiencing it going into a tight turn I never want to again if I can help it. Right now I have one set of 305s and one set of 315s equally worn, at this point I can combine them into 2 staggered setups, so that's what I'm going to do. I also don't notice huge differences in wear front to rear so I don't think it's going to cost me much in tire budget.

I will have to change wheels but SM-10 are on sale right now, should only cost me a few hundred bucks or so. I'll also get to get rid of those longer front wheel studs, lol.

To OP, you do get more oversteer with a square setup, and this might work well on track, but without other changes it makes corner exit pretty sketchy for autocross, as I have the nannies all off. If you're using PTM modes it won't matter as much, but stability controls will be more active. As far as it being faster, there's no great way to compensate for tire type or condition unless you get 2 sets of brand new tires. There's no doubt you're faster but imo it's important to understand exactly why.

[VR Baron]

Originally Posted by DaveC113

The '19+ cars do have ice mode, but it's less likely to activate during track use vs previous models. M Squared says his '20 gets it a couple times a season. The GM engineer on the AX thread says '19+ is more robust for use with different tire setups, but he does not say there's no ice mode at all. I got a '19 ABS module from ebay on the way, that will help a lot, but it's well known that a staggered setup reduces the likelihood of ice mode too. After experiencing it going into a tight turn I never want to again if I can help it. Right now I have one set of 305s and one set of 315s equally worn, at this point I can combine them into 2 staggered setups, so that's what I'm going to do. I also don't notice huge differences in wear front to rear so I don't think it's going to cost me much in tire budget.

I will have to change wheels but SM-10 are on sale right now, should only cost me a few hundred bucks or so. I'll also get to get rid of those longer front wheel studs, lol.

To OP, you do get more oversteer with a square setup, and this might work well on track, but without other changes it makes corner exit pretty sketchy for autocross, as I have the nannies all off. If you're using PTM modes it won't matter as much, but stability controls will be more active. As far as it being faster, there's no great way to compensate for tire type or condition unless you get 2 sets of brand new tires. There's no doubt you're faster but imo it's important to understand exactly why.

I don’t get ice mode as I said. Not sure why and regardless of what gm says, but I will take it! Only two times I may have noticed a tiny bit, if it was, and it was more of a momentary front tire slip then re grab during braking . No hard pedal.And that was going downhill and braking at 70 through the timing lights..lol