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Old 02-24-2012, 07:27 AM   #13
Topless
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Join Date: Nov 2006
Location: Southern ID
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Quote:
Originally Posted by LAP1DOUG View Post
About a year ago, GRM magazine did a test to confirm that a light weight wheel and tire improved times on an auto-x course. They used a Miata for the test, and found that the heavier weight wheel was actually faster!

After examining the data, it was apparent that the heavier wheel was faster just because that wheel/tire combination was just a bit smaller diameter, and thereby lowered the effective gearing and improved acceleration. Just a fraction of an inch less diameter completely over-rode the weight effects of a heavy wheel.

So, you should probably look at the whole package of resulting wheel / tire diameter, sidewall stiffness, etc. rather than being overly concerned about the last ounce of wheel weight.
I agree with your conclusions Doug. What a goofy test though. If you want to test the advantages of lighter wheels you must start with identical wheel and tire sizes and diameters.

Bottom line: You can find quality 17" Porsche takeoff 17 x 8.5 wheels that weigh 21 lbs for around $125ea on CL or you can buy ultra lightweight (18lb) racing wheels for $2500 ea. Shaving 12lbs of unsprung weight might buy you 2/10sec per lap. Are there more efficient ways to spend your $10k that will yield higher performance? Adding a 3.8L motor (2-3sec)? Professional coaching by Andy Lally (8sec)? Tires (5sec)? Suspension (2sec)? The low hanging fruit is always the driver, not the wheels.
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