Another active drag control?
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Joined: Aug 2014
Posts: 68
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Another active drag control?
Before I start I've searched and couldn't find a definitive answer on tire sizes. I have a 2011 base with a z06 rear end conversion I just ordered Weld RTS 18x9.5 18x11 im going to run a M/T 345/18/35 rear tire. What tire size do I need to run on the front to prevent this message? Remember it's still a base front end... Thanks
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,108
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Usually it's a good idea to resolve all those possible issues before you order stuff. 
You do the math, because I'm not doing it for you.
Find the circumference of new OEM tires and the tread depth. Calculate the front to rear ratio of new on the front and bald on the back. Then repeat reversing bald and new. Now you have the ratio limitations that are assured to fit within the computer programming. Try to pick tires that fit near the center of those ratios. Once you determine the rear tire size, then calculate the diameter at half the tread depth and enter that in the tune to correct your speedometer, since I assume this is just for show on the street.
You do the math, because I'm not doing it for you.
Find the circumference of new OEM tires and the tread depth. Calculate the front to rear ratio of new on the front and bald on the back. Then repeat reversing bald and new. Now you have the ratio limitations that are assured to fit within the computer programming. Try to pick tires that fit near the center of those ratios. Once you determine the rear tire size, then calculate the diameter at half the tread depth and enter that in the tune to correct your speedometer, since I assume this is just for show on the street.
Drifting
Joined: Mar 2013
Posts: 1,841
Likes: 21
From: toms river new jersey
ooo no can u run 345 on an 11? thought it was 12 rim..i have them on a 12 rim..i am looking at m and h 325 /45 tires now ......I solved the active drag light by keeping fronts at 35 lbs and rears at 32 hot,,285/35 got me the light...so 295/35 would have been better for me....but I have a c6 z06
