badnewsbeers92

Has anyone had issues with traction control kicking in after going up in wheel size? Old setup was 19’s in the back and 18s up front running 305/30/19 and 265/35/18. New wheels are 20’s/19’s running 295/30/20 and 255/35/19. On the old setup I had the car up to 165 with zero issues on a couple occasions. With the new setup it seems like every time I get to around 110-120mph the traction control wants to kick in. I still have yet to have the new TPMS sensors paired, but that shouldn’t have any effect, right? Anyone dealt with this issue before when bumping up to 20’s in the rear and what’s the fix? Besides turning TC off. Driving an ‘08 Z51 M6.

FatsWaller

There's lots of threads about this. The nannies assume a stock ratio between the front and rear tire diameter. There's some allowance for cases where front or back are new, and the other very used so tread depth is less. I'd figure 1/4 " difference in that case. Overall tire diameter would be 1/2" less. Figure out what those ratios are and if you are much outside of them the nannies will complain.

badnewsbeers92

So am I correct to assume if outside those diameters the nannies will complain? Or is there a remedy someone has found? Ie is this something an experienced tuner could fix? Or I guess I could just turn the TC off completely if I plan on doing any spirited highway driving in Mexico 😎 Until it’s time for a new set of tires of course.

FatsWaller

Look at posts #4 and #5 here: https://www.corvetteforum.com/forums...tolerance.html
Ideal ratio is 1.04%. That thread claims 1.08% worked, 1.1% did not. What ratio are you at now?

As far as a remedy is concerned, you'd have to change the firmware or a software table in the system somewhere if that was even possible, but that's way over my pay grade. You might (probably will) get a better answer if you asked this in the C6-tech-performance forum.

badnewsbeers92

Thanks for the info. Given that information my ratio is at 1.038%. Rear tire diameter is 27” and front is 26”.

FatsWaller

That seems pretty close to the stock ratio. I'd still be asking this in the tech-performance forum.

gdmoore01

You mentioned that the TPMS sensors in some of your wheels haven't been initialized & paired to the system. Pretty sure the Traction Control works in conjunction with the TPMS. I had a problem with a low tire on my 2013 Grand Sport and the TC system kicked in and darn near ran me off the road and the DIC message indicated I had to stay under 50mph to drive home. Get your TPMS connected and see if that helps.

GD

badnewsbeers92

Thats what I was initially thinking too but had a couple people tell me that shouldn’t be causing issues. But to me that would make sense. Only happens around 120mph though so who knows. I’ll take it by the Chevy dealer soon and have them pair it up. Thanks for the input man!

EvanZR1

TPMS will absolutely cause issues. Always make sure all TPMS sensors are initialized and working properly as the first step in troubleshooting TC/AH issues. I don't remember for sure, but I believe there actually is a speed limit when the TPMS is not initialized/working, and if I remember correctly it's somewhere around 120MPH.

badnewsbeers92

Awesome, that’s great to hear. Hopefully that fixes my issues. I’ll update here once I get them paired and let you know if that fixed the issue. Thanks man!

badnewsbeers92

Well I got the TPMS sensors paired and still having the same traction control issues around 120. Guess I’ll just have to put it in competitive mode anytime I plan on doing anything high speed.

EvanZR1

You need to fix it not try to work around or ignore it. Issues with TC/AH can occur even if you put it in comp mode or turn it off (speaking from personal experience on this). Based on your original post, it shouldn't be a tire size issue as you're previous tires were the same diameter offset (1" larger rear) as your new tires. Although I will say that stock difference is 1.2" and while some people say it's a % difference allowance, I've also seen others say you can go larger but not smaller difference. Personally I've never tried a smaller diameter offset than stock, but have done larger on multiple cars with no issue. Anyway, you need to have someone with the proper tool check to see what code it's showing, maybe you just coincidentally have a wheel speed sensor going bad, but my guess is it's tire size related. Keep in mind, not all tire manufacturers are exactly the same, so rough numbers I gave above show them as the same diameter, they new tires could be slightly off (i.e. maybe the new 295s are slightly smaller or the 255s are slightly bigger), causing enough difference for it to cause an issue at higher speed.

FatsWaller

Do you still have the old wheel/tires? Is the rubber still safe? If so, I'd be putting them back on to see if the problem persists. If the old setup still works, then it's got to be the new setup causing the problem. If the old setup no longer works, something else needs attention.

badnewsbeers92

Yeah I wish I knew of someone reputable around here that could fix my issue. Hell, the guy at the local Chevy dealership left it in gear and stalled it when trying to pair the TPMS sensors 🤦🏻‍♂️ So definitely no one competent there lol. Had to explain to him that the car had to be in accessory mode to pair the sensors...

badnewsbeers92

No I sold them the day I got my new wheels on so unfortunately can’t check that. But it’s highly likely it’s caused by the new setup. I’m thinking I should’ve went with 295/25/20 and 255/30/19 based off what I’ve seen on another thread. And if it’s a wheel diameter issue I believe there is nothing I can do except try a different tire size once it’s time to get rid of these. Really don’t go over 120 all that often anyways. Most of my occasional roll racing is 30-110ish range anyways. Incentive to be slightly less irresponsible I guess 😅