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Old 10-31-2020, 05:53 PM   #38
lt4camaro


 
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Drives: 2021 LT1 10 speed auto
Join Date: May 2013
Location: Connecticut
Posts: 2,343
Quote:
Originally Posted by Yosh6 View Post
Couple of points. I'm not a tuner, but I'm pretty sure of these two things. 1. If the tire height in the rear is changed from stock, the speedo calibration in the tune has to be changed because a taller/shorter tire will change the VSS revolutions per mile. Not making this change to match tire height will give the transmission false data for shifting. 2. Mismatching front to rear tire height can result in a StabiliTrak nightmare. This one I know first hand. I tried 26's in the rear and left the 28's on the front. StabiliTrak went mad and put the car in limp mode. I don't know how much of a mismatch you can get away with, but my car will not tolerate a 2" difference. I'm running 28's on all four corners after Bret @ Pray educated me on this. BTW, you cant just assume that you will get EXACTLY 28" tires when you buy them. The number for the calibration comes from an actual measurement of the tire height on the car, on the ground with the correct air pressure. My Micky "28's" are actutally 26.83". Photos FYI only for reference, suggest you get a tuner to get things right, or consult before you go in a certain direction.
The car will tolerate 1 inch tire diameter diff no problem. Can go to a 27.7 to a 26.7 with no issues and tire size diff front to rear will tolerate the 1 inch difference also.
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