Not sure why it wouldn't let me do it in PM. 
Running a 28 inch tire
Burning Brakes
Joined: May 2017
Posts: 1,146
Likes: 170
From: Friday Harbor WA
Melting Slicks
Joined: Jun 2006
Posts: 2,497
Likes: 261
From: Miami Florida
Former Vendor
Joined: Apr 2012
Posts: 9,270
Likes: 81
From: Riverside CA
St. Jude Donor '12
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Burning Brakes
Joined: May 2017
Posts: 1,146
Likes: 170
From: Friday Harbor WA
I'm relatively new here and am no expert, but it is my understanding as long as the front and back tires are within an inch to 1-1/4" in diameter of each other you should be alright. You'll have problems with a 2 inch diameter difference.
Last edited by TomdaToolman; Nov 21, 2017 at 12:02 AM.
Le Mans Master
Joined: Apr 2013
Posts: 5,376
Likes: 1,118
The real challenge is finding a tire, any tire, that matches the specified diameter. I run Nitto NT05R 345/30/19s as a daily drive tire. They’re supposed to be 27.36” diameter, but they’re closer to 26.5”.
The M&H 325/45/17s that I have are supposed to be 28” dia., but are actually only 27.5” dia. And front runners are just as bad or worse, the M&H 185/55/17s that I have are supposed to be ~ 26” dia., but they are actually not even 25” tall (24.75” measured, loaded @ 40psi)
Having said that, I’ve run the M&H 185 front runner (@ 40psi cold) and 325 (@ 18-24psi cold) combo on my car for many weeks, albeit for relatively short trips (less than 10 miles per drive) without triggering the AH MIL. I always switch off the traction control, which some folks say makes the difference.
I don’t know if there is an actual, true 28” diameter tire that fits on the C6 without rubbing problems? I think the biggest tire that will fit is the M&H 325/45/17 and that rubs slightly on bumps.
The M&H 325/45/17s that I have are supposed to be 28” dia., but are actually only 27.5” dia. And front runners are just as bad or worse, the M&H 185/55/17s that I have are supposed to be ~ 26” dia., but they are actually not even 25” tall (24.75” measured, loaded @ 40psi)
Having said that, I’ve run the M&H 185 front runner (@ 40psi cold) and 325 (@ 18-24psi cold) combo on my car for many weeks, albeit for relatively short trips (less than 10 miles per drive) without triggering the AH MIL. I always switch off the traction control, which some folks say makes the difference.
I don’t know if there is an actual, true 28” diameter tire that fits on the C6 without rubbing problems? I think the biggest tire that will fit is the M&H 325/45/17 and that rubs slightly on bumps.