http://www.michelin-green-meter.com/main.php?cLang=en

I came across this "cute" Website done by Michelin while registering my snow tires (discussed on previous thread). If you are not clear on what LRR tires are about, and why it is the action of the tire (flex), and not its traction that is the important parameter, watch the video in the "Green Tire Technology" tab.

Even if you already know the theory and advantages of LRR tires, there is a lot of good stuff here to explore. Also sorta fun for non techinical types.

It is the ignorant among us that will eventually destroy us all.

First I want to thank you for the link. However, Michelin is doing themselves no favors and in fact, making me into a grumpier old man. For Michaelin:

Ok, so what is the ranking in rolling resistance between:

• Energy 3A
• Primacy HP
• Latitude Tour HP
• Alpine 3
• Pilot Alpine 3
• Primacy Alpine 3
• Energy LX4
• Energy MXV4 Plus
• Energy MXV4 58
• Energy MXV8
• Energy XM1+

Just within one manufacturer, 11 different tire models and not one of them has a rolling resistance metric. Just a bunch of weasel words numbers compared to some unidentified "competition." How is anyone to make an informed choice except by going to independent testing services like Consumer Reports.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

Yes, I agree that a label standard is badly needed, and not only by Michelin. I think California is going to make it mandatory in the next few years, so hopefully we will get a decent metric soon.

There are some words, if not metrics, on the Michelin website in the section on LRR research that hints at what is going on. Also, the Michelin American reps are very responsive if you ask them for data outright (but they are hard to reach). The one I talked to before buying the Primacy snow tires was very aware of rolling resistance. He indicated that the Primacy line would eventually replace the entire Energy line -- the reason being improved chemical composition for flexing. As I understood him, the Primacy was basically the next generation of the Energy series.

Incidently, although I have no empirical data because of other seasonal variables like termperature, lower winter driving speeds and different road surface conditions, I have come to the conclusion that the RR ratio for the Primacy Alpin PA3 winter tire is actually equivalent to or better than that of the Energy MXV4 OEM road tires. I think this is the case because my winter FE has not dropped as much as I anticipated (only about 1.8 MPG, average so far this winter) and becasue I know the winter tire is more flexible due to the winterization oil additives. If it were not for the softer compound, and the effect it has on tread wear, I would probably run the winter tire all year long.

It is the ignorant among us that will eventually destroy us all.

I commend Michelin for making efficiency a priority. My Saab 9-5 came with Energy MXV4 Plus tires which must have made a significant contribution to MPG since the car will consistently achieve 30mpg on the open road at a true 70-75mph. Not bad for a luxury sports sedan with a turbo. I recently replaced the worn tires with the new MXV4 Primacy's. Same mpg, but even quieter and smoother with better wet grip (subjective, since prior set worn).

I intend to put these tires on every car I own.