Interesting analysis of MPG effect of replacing worn tires with new ones. Excerpt: Conclusion While many of these individual differences may seem insignificant, it is easy to understand that when they are added together, the new tires may appear to reduce vehicle fuel economy. It also means that a Toyota Prius appearing to get 50.0 mpg just before replacing its worn-out tires with new tires of the same brand, type and size, might be reduced to registering just 47.25 mpg afterwards, even if all of the driving conditions were identical. Remember, "your mileage may vary." Full article is at: Tire Tech Information - Tire Rolling Resistance Part 3: Changes to Expect When Switching from Worn-Out to New Tires
Great article! Maybe this should become part of the KB section even though it's not Prius specific. The high mileage of the Prius really magnifies the percentage effect along w/Prius owners' tendency to care or monitor their mileage.
Interesting. I have noticed this before on three other cars--a VW and two Acuras--and it was indeed noticeable upon switch-out. I attributed it to larger diameter and different tire characteristics, but the material hardening with age and thus less rolling resistance makes sense. (And hey--it's before 5AM, and I already learned a new term--'rubber squirm'! By any reasonable measure, today should be a good day!) CHeers ~T
I changed the factory Yoko Avid tires, 195x65x15, to Michelin Energy Saver tires,, 195x65x15 at 11,000 miles. I now have over 16,000 miles on those Michelin tires. All 4 have 44psi of Nitrogen. When I first purchased I noticed a 2-4 mpg increase over the Yoko Avid tires. Those Michelin tires continue to deliver the MPG's that Michelin promised. alfon
I use helium in my tires because it makes the tire almost weightless which increases gas mileage and increases tire life.
But then road noise becomes very high pitched and you can only refill your tires from clowns. :focus:
