Tire Size Help, Traction Sys Active issues
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7th Gear
Joined: Mar 2023
Posts: 7
Likes: 3
Tire Size Help, Traction Sys Active issues
Hi folks,
I've been having the "Traction Sys Active" kick in when going above 55mph or so, but no other error codes appearing. Upon searching the forums, I think I've found my issue: the diameter of the front/rear tires are wrong. Per the posts, I need the rear tires to be at least 0.5" to 1.5" larger in diameter than the front tires. But my rears are somehow slightly smaller:
Front: 255/40ZR-17
Rear: 285/30ZR-18
Both front and rear tires are in very good shape, so if possible to keep using one set, that would be much preferred. At least for now. The other slightly complicating factor is that I don't know anything about the wheels currently on the vehicle. The pattern makes it look like the C6 Z06 wheels but I assume they are knockoffs. But there doesn't seem to be an easy way to find the dimensions. I would also like to keep using the wheels.
Of the tires currently on the C5, which would folks recommend replacing, the front or the rears? And with what size tire? Or are both front/rear tires just not salvageable and do I need to replace all 4 tires? I'm playing with the calculators now but wanted to get my work double checked before I pulled the trigger. I'd rather not screw this up!
Thank you!
Edit: I should add, the C5 is being driven as a daily, with occasional spirited driving on the weekends. Not being tracked or anything. But would still like for it to perform as well as it can.
I've been having the "Traction Sys Active" kick in when going above 55mph or so, but no other error codes appearing. Upon searching the forums, I think I've found my issue: the diameter of the front/rear tires are wrong. Per the posts, I need the rear tires to be at least 0.5" to 1.5" larger in diameter than the front tires. But my rears are somehow slightly smaller:
Front: 255/40ZR-17
Rear: 285/30ZR-18
Both front and rear tires are in very good shape, so if possible to keep using one set, that would be much preferred. At least for now. The other slightly complicating factor is that I don't know anything about the wheels currently on the vehicle. The pattern makes it look like the C6 Z06 wheels but I assume they are knockoffs. But there doesn't seem to be an easy way to find the dimensions. I would also like to keep using the wheels.
Of the tires currently on the C5, which would folks recommend replacing, the front or the rears? And with what size tire? Or are both front/rear tires just not salvageable and do I need to replace all 4 tires? I'm playing with the calculators now but wanted to get my work double checked before I pulled the trigger. I'd rather not screw this up!
Thank you!
Edit: I should add, the C5 is being driven as a daily, with occasional spirited driving on the weekends. Not being tracked or anything. But would still like for it to perform as well as it can.
Last edited by Hobbes259; Mar 18, 2025 at 10:25 PM.
Pro
Joined: Apr 2004
Posts: 536
Likes: 85
From: McKinney TX
Not sure what your issue is, but I ran the same size front and rea, commonly called :"square setup" on two of my C5's without any traction control issues, I would troubleshoot more before buying anything new
