...because of the mileage penalty incurred for the first 1000 or so miles until the new rubber gets broken in. After the break-in, the mileage will steadily increase over the course of the tire's life and will be at its highest when the wear marks appear on the treads. I've experienced this MPG drop every time I've had to replace the tires on my car. This time I replaced my Michelin RainForce (with 70,000 miles on them) with Michelin Harmony tires. They discontinued the RainForce and the Harmony is the most similar tire Michelin is currently selling. Its been getting harder to find tires in my car's size each time I've had to replace them. In the process or re-tiring my car, I went from around 52MPG for my past several tanks to 49MPG for my first tank on the new tires and this second tank looks like it will be about the same.

I suspect the mileage drop from new tires has several causes. The deeper treads on a new tire create more aerodynamic drag than the shallow dimples of a worn out tread (closer in form to the low drag dimples of a golf ball). Also as the thick rubber on a new tread flexes, it creates more heat then the thin rubber of a worn out tread. Rubber also gets harder as it ages and loses its plasticizers. A harder tire has less rolling resistance than a tire consisting of a softer rubber. But the drop in coasting ability was instantly apparent as soon as I started driving on the new tires.

Out of curiosity, I was wondering why you stayed away from the Low Rolling Resistance tires (Bridgestone B381 and Michelin Energy)? It seems they attempt to have the characteristics you mention, but they are this way when new (harder rubber, better coasting, less aerodynamic drag).

dasjoos, dont forget the extra weight from the unworn rubber that must be accelerated each time the car moves.

Hidden Views Photography

Chuck, I investigated LRR tires, but unfortunately, they don't make them in a size that will fit my car.

I don't consider myself a tire expert, however I'm very interested in what new, better quality, tires will be like when I finally replace the OEM Integritys. Honestly, I'm not that impressed with the Good Year Integrity. They seem pretty typical of factory tires. Good enough to keep you on the road for 30,000 miles, but not much beyond that.

I read in a forum once that the mileage hit with new tires is caused by the sharp, just molded, edges on the tires. And with a few thousand miles those edges get worn down and resistance reduces to a normal level.

It has been said:
Hybrid drivers come in 3 flavors, greenie, techie and cheapie. Pick any 2.
2005 Prius, Melinium Silver over gray, package 5 (AI)

Time to get out an exacto or some other blade and knock of those hard edges

My hydroponics experiment

You ever notice how hard it is to lip read cartoon characters?
"Crazy is what the sane call Delta Flyer"

It took about 2000 miles, but now my MPG's and coasting speeds are finally getting back close to normal.