Mohtalim

I just saw a commercial that claimed Michellin tires are the most fuel efficient tires on the road. How could properly inflated tires affect fuel efficiency? I guess you could have lighter tires, but they'd wear out faster and be less safe, so I'm not sure that's a selling point.

Actually, harder tires would be more fuel efficient, but they're likely less safe since they wouldn't grip the road as well... Dave, you're our resident MechE who did plenty of tests on tires if I recall. Feel free to chime in!

maybe this?

http://www.mpgomatic.com/2008/08/21/tire-inflation/

Right, that's why I said properly inflated in my original post. I know underinflating reduces efficiency.

Hardness does not necessarily mean how inflated it is, but how hard the rubber is as well...

Clearly my reading comprehension skills have deteriorated.

When I worked for Goodyear, they basically admitted Michilin tires were better and had divisions reverse engineering them. This was aircraft tires, but yah know... maybe they have a certain layering pattern that sucks less?