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      10-17-2017, 06:49 PM   #4
dc_wright
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Drives: 2006 Z43.0si Roadster
Join Date: Oct 2014
Location: Orlando, FL

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Quote:
Originally Posted by joelselman View Post
Not really familiar with your car/tire, but wouldn't you want a square setup if you're trying to reduce understeer?
You can eliminate understeer and actually transition to an oversteer condition if you go skinny enough on the rear tires. The problem though is that while you now have over steer you may be significantly slower because you've reduced overall grip.

Quote:
Originally Posted by in2twins View Post
Should I use 265-35-18 or 275-35-8 Rear tire on the stock wheel for autocross? Smallish course with slow corners.

In an RE71R both are a 9.5 measured rim. I was tending toward the 265 for the smaller diameter and faster out of the hole and can lower the car more later.

For front I was headed 245-40-18 as I was looking for the best tire to reduce understeer on the stock suspension

Experiences?
The RE71's have extremely stiff sidewalls and in my experience they don't like much pinch fit. I had 275/35 x 18 on 18 x 8.5 wheels and the pinch fit coupled with the very stiff side walls caused the shoulders of the tire to be very rounded. I dropped down to 265/35 x 18 and actually get about 5 mm more contact patch width.
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