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Old 10-09-2011, 09:37 PM   #1 (permalink)
MetroMPG
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Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 21,007

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 53.47 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 73.57 mpg (US)
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Lower rolling resistance: space saver spare tire donuts @70 psi, or RE92's @ 51 psi?



Just for fun: what do you think would win a slow speed coast-down test, all else being equal:
  • four Bridgestone Potenza RE92 LRR tires @ 51 psi (OEM tire installed on the first-generation Honda Insight)
... or ...
  • four Goodyear space saver spare tires @ 70 psi (OEM donut provided with 1991-2008 Metros, Fireflies & Swifts.)
Today I did a comparison of the rolling performance of all the different tires in my expanding Suzukiclone fleet. I tested everything at 51 psi on one car (the ForkenSwift) in repeated coast-downs. (My life is so exciting. )

For kicks, I also threw the spare tires into the shoot-out, testing at both 51 & 70 psi (sidewall says: "inflate to 60 psi"). Why? Because these wee tires seem to regularly find their way into discussions about RR, wheel/tire aero & weight... sometimes in a speculative, hopeful way.

I will say this: I was surprised.

Will post the details/results tomorrow!


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EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
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