Importance of diameter for competition tires
Thread Starter
Senior Member
Joined: May 2004
Posts: 474
Likes: 36
From: Central Ohio
2017 C43, 1966 230SL, 2006 Jeep Rubicon
Importance of diameter for competition tires?
I'm shopping for competition tires (first time on this car, 2017 C43) and it is difficult to find a set for stock staggered 18" or 19" wheels, or even fitting on +1 inch wider wheels than stock. I'm trying to stay close to the stock diameter of 26.0 inches. Is that important? For example, this set of Toyo R888R - are they too small? Does it matter?
Front https://www.discounttiredirect.com/b...-r888r/p/40831 25.39"
Rear https://www.discounttiredirect.com/b...-r888r/p/40828 25.31"
I assume nobody goes with a square setup with, for example, 8.5" wide wheels on all 4 corners? I know the offsets would be different, but the tires would be the same.
Thanks for your input.
Front https://www.discounttiredirect.com/b...-r888r/p/40831 25.39"
Rear https://www.discounttiredirect.com/b...-r888r/p/40828 25.31"
I assume nobody goes with a square setup with, for example, 8.5" wide wheels on all 4 corners? I know the offsets would be different, but the tires would be the same.
Thanks for your input.
Last edited by GermanCarShow; May 4, 2022 at 06:32 PM.
square set up would be ideal, would counter balance the understeer.
within 3% is the go to for diameter. 235/45/18 would be closer but adds rotational mass and roll over - which, without proper suspension modification is a moot point I guess. K3's with stiffening braces would be at the top of my list. Even then you'll be wanting more. It's a big heavy car that wallows in turns.
within 3% is the go to for diameter. 235/45/18 would be closer but adds rotational mass and roll over - which, without proper suspension modification is a moot point I guess. K3's with stiffening braces would be at the top of my list. Even then you'll be wanting more. It's a big heavy car that wallows in turns.
Thread Starter
Senior Member
Joined: May 2004
Posts: 474
Likes: 36
From: Central Ohio
2017 C43, 1966 230SL, 2006 Jeep Rubicon
I had not thought of that, interesting point. Do others with significant track time want to back that up?
Within 3% difference between front and rear? Or, within 3% of stock 26.0" diameter? My example R888R's are nearly identical front and rear, but are near the 3% limit from stock of 25.22".
Well, I know it's not a 911 or Elise. And I'm no pro, so the car has better skills/limits than me. I'm just getting started. I'm thinking wheels & tires this year. Maybe brakes next year. Suspension would be after that, eventually (biggest cost). This is my daily driver that I just got last week, so the wallet is a bit light and I'm only planning a few events this year. I get more vacation days next year!!
Within 3% difference between front and rear? Or, within 3% of stock 26.0" diameter? My example R888R's are nearly identical front and rear, but are near the 3% limit from stock of 25.22".
Well, I know it's not a 911 or Elise. And I'm no pro, so the car has better skills/limits than me. I'm just getting started. I'm thinking wheels & tires this year. Maybe brakes next year. Suspension would be after that, eventually (biggest cost). This is my daily driver that I just got last week, so the wallet is a bit light and I'm only planning a few events this year. I get more vacation days next year!!
