Quote:
Originally Posted by CapriRacer
Ernie,
I am sure you are aware that new tires will have more RR than worn out tires - all other things being equal. I'm wondering how you account for that when you purchase new tires.
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Hmmm,
I KNOW I wrote a long reply to this question, but it's not posted. Hmmm.
My laziness is controlling tonight, so I won't reconstruct that reply--here's the short version. I'm not so sure that new tires are worse just because the tire is thicker through the tread area. I did a calculation and found that for my particular car, just the extra diameter of a new tire potentially raises fuel efficiency by about 2%. (Improves engine RPM.) And, I think a new tire loses less energy due to squirm because the deep tread allows more lateral flexibility.
I said to watch for a change in mpg with the new tires. I have an embarrassing story to tell--
I just got on a new set of tires last week. To save money, I went to a lower-quality tire--went from Michelin Energy MXV4 S8 (one of the very best) to a much cheaper tire, the Michelin Energy MXV4 Plus, apparently now on close-out by the factory.
Well, just watching my ScanGuage, it looks like my mileage has dropped by about 4 or 5 mpg, an 8% drop in fuel economy for my car.
I'm disgusted. I could take them back, but a set of S8s just isn't in my budget right now. Hmmm
Ernie Rogers