[arpad_m]

Originally Posted by grampa_ss

Try this one on. I also run my 26" rear drag radials. Again, stock front is 245/40/20 rear are 305/35/18 - 26.4 which is over 1 inch shorter. Still don't have issues. Go figure.

Grampa, we're all armchair quarterbacking here without engineering level responses from the horse's mouth. There could be several reasons, maybe the check only works in one direction (taller rears, not shorter), maybe it has an activation threshold that you never hit because you turn the nannies off when using your drag radials, etc.

This is the very kind of question we could've asked in the Ask Al forum, had it gained a bit more traction with the team... I'm not complaining, though, it's already fantastic that we got the answers we did.

[grampa_ss]

Originally Posted by arpad_m

Grampa, we're all armchair quarterbacking here without engineering level responses from the horse's mouth. There could be several reasons, maybe the check only works in one direction (taller rears, not shorter), maybe it has an activation threshold that you never hit because you turn the nannies off when using your drag radials, etc.

This is the very kind of question we could've asked in the Ask Al forum, had it gained a bit more traction with the team... I'm not complaining, though, it's already fantastic that we got the answers we did.

agreed. And yes, I do turn the nannies off and also have my tire size adjusted in each of my tunes. I have a 26" & a 28" tune.

[z28deuce]

Small point, but when you're talking about rake you'd use the tire radius since it defines the distance from the ground to the wheel/tire centerline and therefore the car's ride height. This means it's actually half the diameters and differences noted above.

For speed and traction control calculations using the difference in tire diameters would be correct, though, since the applicable factor is the distance traveled per rotation. This is based on the tire circumference and circumference equals pi x diameter.

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[Fraxum]

Been there done this. Stabilitrac issue OP. Back and front tires have to be less than one inch height difference. stick with the SS1LE and ZL1 sizes. Still moving the connector is a must on your SS. Chevy fixed that in 2019 I think. Good move there.

[FlukeSS]

Originally Posted by arpad_m

This was discussed several times, your combination of 275/35/20 fronts with 305/35/20 rears introduced a new ~3.3% front/rear bias and even inverted the rake.

I don't know the exact tolerance thresholds for the ABS and Stabilitrak, but it's somewhere around 3%, which means you are very close, and depending on tire pressure and the exact height of your Nittos, the bias may only trigger these errors occasionally. Maybe others are straddling the threshold with a bit more luck, adding extra pressure up front and letting air out in the rear, or running different tires that have a slightly different outer diameter.

Since you ruled out the proper fix from the get-go, what you can do is up your front size to 285/35/20 and add 3-5mm spacers to clear the strut perches. Although not ideal for a 9.5" wheel, this will bring the bias down to 2.2% and you will be fine.

Have to agree here, 305's on the rear. It is recommend 305/30/R20's 30's have no TC issues as far as I'm aware, I just put those on my car. No TC issues, no spacers required, just direct fit.

[FlukeSS]

Originally Posted by Fraxum

Been there done this. Stabilitrac issue OP. Back and front tires have to be less than one inch height difference. stick with the SS1LE and ZL1 sizes. Still moving the connector is a must on your SS. Chevy fixed that in 2019 I think. Good move there.

StabiliTrack can be disabled.

But you have to run in Track Mode, with TC off, and double tap to turn on Comp Mode.

Then all of the TC systems are disabled.

Note: This does NOT work in Sport mode. TC is off, but StabiliTrack will remain enabled.

Also if by connector you mean the wiring harness in the rear driver side wheel well I do not believe this was fixed. I am getting a rubbing noise from my car that I can't identify. (I need to have it checked if I need to get the wire rerouted) :(

Check your PM I'll send you the video.

[1ssa_camaro]

UPDATE: Got my tires aligned, installed the OEM tmp sensors from stock wheels. Issue has not come back since.