does rim size affect handling????
Club240 Staff
Joined: Jun 2004
Posts: 483
From: tampa, fl
I am building a all-around handler biased towards road courses. I have 17X8s in the front wrapped in 235/45/17 Proxes4s and 17X9 245/40/17s on the rear. Once the fronts wear, I will be dropping down to 225 in the front as the 235 is juuusstt a bit too heavy.
While the car now has PHENOMINAL grip and near perfect feedback, it is markedly slower due to the wider contact patch (increase in rolling resistance) combined with the diameter increase. The engine works noticeably harder to move the car and my fuel mileage has plummeted. I estimate that I will need to find about 15 - 20HP to overcome the width increase.
Not that I am really complaining, the car sticks to EVERYTHING and I havent chosen coilovers or what I am doing to the engine. It's a problem that will disappear soon.
While the car now has PHENOMINAL grip and near perfect feedback, it is markedly slower due to the wider contact patch (increase in rolling resistance) combined with the diameter increase. The engine works noticeably harder to move the car and my fuel mileage has plummeted. I estimate that I will need to find about 15 - 20HP to overcome the width increase.
Not that I am really complaining, the car sticks to EVERYTHING and I havent chosen coilovers or what I am doing to the engine. It's a problem that will disappear soon.
For the Club240 Time Attack car, we will be going much more agressive with probably a 255/285 combo to start, but we will be working off nearly 500whp, serious aero, and about 2150lbs. Even with this, we may have to go smaller on the front
Registered User
Joined: Mar 2007
Posts: 43
From: East Coast
Thanks man. It's fun to be able to apply the same concepts on my street car.
On our GT 360 (2002 and 2003 Rolex Champion car,) we actually have fronts that are only slightly smaller than the rears and a much larger offset. Full splitter, wing, and aggressive DF package that really came in handy on road courses since the front width was just huge. Hurt at Daytona and Phoenix on the banking, but you pick your battles, you know? Speed through the turns... Sounds familiar...
Factory Challenge (500HP, 350 lbft) cars only run 235s in front and they are scary sticky through turns. Turn-in so fast we've had new drivers get queasy. Stock bodies, though. No aero. The GT 430 is sikkk.
When you test have all of your size options ready to go.
On our GT 360 (2002 and 2003 Rolex Champion car,) we actually have fronts that are only slightly smaller than the rears and a much larger offset. Full splitter, wing, and aggressive DF package that really came in handy on road courses since the front width was just huge. Hurt at Daytona and Phoenix on the banking, but you pick your battles, you know? Speed through the turns... Sounds familiar...
Factory Challenge (500HP, 350 lbft) cars only run 235s in front and they are scary sticky through turns. Turn-in so fast we've had new drivers get queasy. Stock bodies, though. No aero. The GT 430 is sikkk.
When you test have all of your size options ready to go.
Last edited by Scuderia; May 1, 2007 at 08:06 AM.
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