Low Rolling Resistance

Looking at tirerack, can anybody tell me why the same tire (Michelin LTX MS/2 for example) in 245/75/16 offers low rolling resistance in the heavier rated tire while the lower rated tire (P) does not even though it weighs much less?

 

A good question for tirerack or Michelin. If you receive a response, please post. Am interested. Maybe it is related to the tread material?

This is interesting: http://www.michelinman.com/US/en/tires/products/energy-saver-ltx.html

 

I don't know for sure... but it makes sense to me.

I would think that the distortion of the tire shape as it rolls would contribute more to rolling resistance than the weight of the tire.

So a stiffer sidewall and higher inflation pressure would keep the tire rounder and create less rolling resistance.

 

Sent email, will report back.