Tire diameters for an AWD 7.2
04-25-2016, 11:31 PM
#1
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Tire diameters for an AWD 7.2
Posted under the 997 forum but good to try here as well.
I am trying to piece together a track dedicated set of rims and tires for my '12 GTS 4. I would have thought that on an AWD system it would be imperative to have F and R diameters virtually identical to minimize driveline 'grind'. However when I look at specs for various tires on TR there is quite a difference between F and R diameters for OEM sized tires. For example, with the MPSC2, the 235/35-19 is 25.5" while the 305/30-19 is 26.3". 0.8" diameter delta! Is that intentional? Does the drivetrain design somehow require the fronts to turn faster than the rears? Seems not intuitive.
My thoughts otherwise, for 8.5"/ 11" F/R rims, would be to oversize the fronts to a 245/35 (dia 25.8") as that is still smaller diameter than the rears . Heck even a 255/35 is smaller than the OEM-spec rears.
Any issues with that?
I am trying to piece together a track dedicated set of rims and tires for my '12 GTS 4. I would have thought that on an AWD system it would be imperative to have F and R diameters virtually identical to minimize driveline 'grind'. However when I look at specs for various tires on TR there is quite a difference between F and R diameters for OEM sized tires. For example, with the MPSC2, the 235/35-19 is 25.5" while the 305/30-19 is 26.3". 0.8" diameter delta! Is that intentional? Does the drivetrain design somehow require the fronts to turn faster than the rears? Seems not intuitive.
My thoughts otherwise, for 8.5"/ 11" F/R rims, would be to oversize the fronts to a 245/35 (dia 25.8") as that is still smaller diameter than the rears . Heck even a 255/35 is smaller than the OEM-spec rears.
Any issues with that?
Last edited by Skid; 04-26-2016 at 01:08 AM.
