265 & 295 fitment
Race Director
Joined: May 2007
Posts: 10,805
Likes: 706
From: Feverish All Over
Width wise you should be fine. You are sticking with C6 rims sizes, but the tire you have proposed for the rear will be 0.88 inches smaller in diameter - anything more than a 1/2 inch deviation is considered a no-no as it messes with speed sensors, etc....
Others may have done it though and they may chime in.
Calculating outer diameter is done as follows:
(width in mm x aspect ratio x 2) divided by 25.4 mm + wheel diameter in inches
Stock Rear = (285 x 0.35 x 2)/25.4 + 19" = 26.85"
Proposed Rear = (295 x 0.30 x 2)/25.4 + 19" = 25.96"
26.85 less 25.96 = 0.88 inches
Others may have done it though and they may chime in.
Calculating outer diameter is done as follows:
(width in mm x aspect ratio x 2) divided by 25.4 mm + wheel diameter in inches
Stock Rear = (285 x 0.35 x 2)/25.4 + 19" = 26.85"
Proposed Rear = (295 x 0.30 x 2)/25.4 + 19" = 25.96"
26.85 less 25.96 = 0.88 inches
Burning Brakes
Joined: Dec 2007
Posts: 1,015
Likes: 1
From: Maryland
St. Jude Donor '08
Width wise you should be fine. You are sticking with C6 rims sizes, but the tire you have proposed for the rear will be 0.88 inches smaller in diameter - anything more than a 1/2 inch deviation is considered a no-no as it messes with speed sensors, etc....
Others may have done it though and they may chime in.
Calculating outer diameter is done as follows:
(width in mm x aspect ratio x 2) divided by 25.4 mm + wheel diameter in inches
Stock Rear = (285 x 0.35 x 2)/25.4 + 19" = 26.85"
Proposed Rear = (295 x 0.30 x 2)/25.4 + 19" = 25.96"
26.85 less 25.96 = 0.88 inches
Others may have done it though and they may chime in.
Calculating outer diameter is done as follows:
(width in mm x aspect ratio x 2) divided by 25.4 mm + wheel diameter in inches
Stock Rear = (285 x 0.35 x 2)/25.4 + 19" = 26.85"
Proposed Rear = (295 x 0.30 x 2)/25.4 + 19" = 25.96"
26.85 less 25.96 = 0.88 inches
I am running Michelin Pilot Sport PS2's on my C6 with 18.00 x 9.5" wide front wheels and 19.00 x 11.00" wide rear wheels.
Tire sizes are:
265/35/18
305/30/19
Traction control, ABS etc is all fine with no codes thrown, but I know that my speedo is not correct and in order to do so would it would require an ECU recalibration as the OEM stock sizes are:
245/40/18
285/35/19
I have wondered as well if I could have the dealer recalibrate the ECU with the Tech II for the tire size change?
Race Director
Joined: Mar 2001
Posts: 10,030
Likes: 10
From: Prescott AZ
St. Jude Donor '04
