Mismatch tire for Tracking
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Navigator
Joined: Feb 2022
Posts: 9
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From: Killeen
Mismatch tire for Tracking
Big debate I am trying to find out. I found a close out sale on 325/25R20 (Continental SportContact 6) for the rear of my C7 GS for 200$. It was a steal and I bought them. I started looking for fronts and ran into the issue that Continental does not make a 275/30R19. Reason I went with that size is to maintain same side wall height from front to rear. Now I’m in debate whether to get a different brand (Falken Azenis) for the front or go with the Continental that are 285/35R19 (but they have a massive sidewall compared to the rear). Will having a different brand fail tech or mess with my performance more then having a bigger sidewall in front compared to rear? This will see couple track days until I get my track wheels and tires. Anyone have a clear answer? I get a lot of different answers and contacted the shop as well that does tech inspection in Austin, TX. Waiting for answer.
Burning Brakes
Joined: Jan 2008
Posts: 797
Likes: 283
Curious why you care about matching sidewall height front to rear. Ideally you want to match what was there originally so that the ABS algorithms work properly as they compare wheel speed to detect lock up. This is also an issue for the traction control function. Also, if you're going to track you should get track tires. Street tires are not designed for extreme temperatures and likely melt and\or chunk the tread right off of them. Plus, well, traction is not their primary focus, wear/ride/noise are also big players of course. And no, they usually don't care about tire brand matching unless a tire sponsor has a REALLY big say in this.
Pro
Joined: Mar 2002
Posts: 732
Likes: 138
From: Allen (DFW) Texas
It's generally not an optimum setup to go with mis-matched front/rear tires, simply because two different tires/brands will have different response/breakaway characteristics that might tend to make the car a bit sketchy depending on your level of experience and "feel" for the car. But if you're only looking at a couple of track days the two you mentioned probably won't be much of an issue, again depending on your level of skill and how hard you push the car. And the C7 is relatively forgiving in terms of varying diameters front/rear as long as you don't vary too much from the stock diameter ratio and remember not to stab the brakes going into a corner (yes, you can induce ice mode via incorrect brake application - been there, done that).
Tech Contributor
Joined: Oct 1999
Posts: 41,058
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From: Charlotte, NC (formerly Endicott, NY)
If you are committing the unpardonable sin of mixing tires the rule of thumb is to always have the best handling tire on the rear whether you are on the street or track. If the best handling tire is in the rear the car will tend to understeer in corners while having the best handling tire in the front means the car will have a tendency toward oversteer. Sidewall height is only one of the factors to be considered.
Bill
Bill
