Does anybody know .....?
Thread Starter
Safety Car
Joined: Aug 2017
Posts: 4,243
Likes: 1,133
From: North Myrtle Beach SC
Does anybody know .....?
if you use taller tires (on rear) I know it can mess up the traction control/stability. If you change to the correct tire size in the computer, will that allow the taller tires with no codes?
Le Mans Master
Joined: Dec 2005
Posts: 6,998
Likes: 1,681
From: Southeast TX
The ratio of front to rear diameter needs to remain the same. Don't think you can change that in the tune and keep the nannies happy. So, if you add a 10% taller tire in the rear, you need to similarly get a 10% taller tire in the front. The rears need to be about 4.6% taller than the fronts no matter how tall the rears are.
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Here's a method that assures the minimum ratio limits and can be used with replacement tires, especially when only replacing one axle pair. BTW, not all tire manufacturers tire data is accurate, but short of measuring the tire properly inflated and on the car, it's all we have.
Find the OD of the OEM front tire and the tread depth. Do the same for the rear tire.
Calculate the circumference of each with full new tread and also when no tread remains.
Calculate the percentage of difference between full tread on the front vs no tread on the rear, then do the same for no tread on the front vs full on the rear. Those are the known limits. It may be more, but GM doesn't appear to let that information be public.
Racer
Joined: Jan 2015
Posts: 375
Likes: 31
From: San Antonio TX
Going with rear tires that are more than an 1" taller than stock while keeping stock diameter front tires has been known, in the 94-96 B-bodies to disrupt/disable the ABS.
KW
Last edited by KW Baraka; Jan 14, 2019 at 11:16 PM.
