[rbpeirce]

I need two rear tires for my 2021 718 GT4. I've been using Goodyear Eagle Supercar 3 but the 295 has been backordered at TireRack for over a year. They do have a 285 and a 305. Any preference? Will the 305 fit? If so, will it cause a tendency to understeer?

I previously read that the 285 is what they run on the Chevy, is widely available and will work on the GT4. I'll likely go that way unless I hear otherwise in the next few days.

[vranko]

As I recall the general rule is to not exceed a 3% difference in diameter front to rear, to insure ABS / stability control doesn't get confused. What is the height of the 305s? Same as the 295s?

[rbpeirce]

Originally Posted by vranko

As I recall the general rule is to not exceed a 3% difference in diameter front to rear, to insure ABS / stability control doesn't get confused. What is the height of the 305s? Same as the 295s?

The diameter of the 245 front is 26.8". The 295 is 27". The 285 is 26.8" and the 305 is 27.2", about 1.5% more than the front.

I checked with my shop and the 305 will fit and that's probably a better choice. Interestingly, both the 285 and the 305 have 7/32" tread depth while the 295 has 8/32". No idea why that is. However, I just need to get thru the season when the fronts will be gone so it shouldn't matter one way or the other.