[6spdhyperblue]

Originally Posted by wnta1ss

Here's what Chevy put for the front tire sizes in the regular SS and the 1LE (non-driven tire circumference). Note how the 245/40-20 F1 runonflat was listed as 2164 mm circumference, then the 285/30-20 F1 Supercar 3 was listed as 2123 mm circumference. Rears list the same for both, but really they are not, the 305/30-20 is slightly shorter than the 275/35, and makes the speedo read a little higher in my experience. Screenshot of stock SS vs 1LE below:


Attachment 1101202

I’ll further complicate this deal with a screenshot of my ‘22 1LE m6 stock file

[SATINSTEEL1LE]

For my ZL1 I run the 17" 305/45 MT ET street SSs. They are awesome on the street and at the track. And I've gotten caught in the rain on them and they worked well driving carefully. Something that happens often here in FL. They fit perfectly.

[SATINSTEEL1LE]

Originally Posted by 6spdhyperblue

I’ll further complicate this deal with a screenshot of my ‘22 1LE m6 stock file

And here's my stock file from my 21 ZL1 a10.

[wnta1ss]

Originally Posted by SATINSTEEL1LE

And here's my stock file from my 21 ZL1 a10.

Interesting that they made the rear tire numbers closer to reality in the newer cars. With the 2017s having the 748 revs/mi in their tune, video of an SS/1LE and a ZL1 going through timing traps showed that the speedo was reading a couple mph high, meaning that the 305/30 tire actually makes more than 748 revs/mi.