[07b2300]

Thanks for all your responses. Both tires take the same max inflation--35 psi. For some reason the X radial carries a higher load at 35 psi (150 lbs more). The 215 is .1" higher so almost identical there, and the 215 has a .3" narrower contact (8.7 instead of 9) so very close there too.

Michelin doesn't put the weight of the X on their website so no idea if the X is any lighter, but probably--the treads are a little shorter in the X (10/32 insead of 13/32) so likely a harder rubber and somewhat lighter at the outside circumference where it counts. Also although both are a P rated tire, they consider the LTX suitable for trucks so is likely heavier...

So without knowing weight or RR of each tire makes it hard to know which would get better mileage. While consumer reports gave the X an "excellent" RR rating in their recent test (and #1 overall out of all tires with an excellent RR rating they tested), a previous test had said one of the benefits of the LTX was RR too. But CR gives no hard numbers and both tires weren't on the same test.

With the info I have I should probably go with the LTXs. Lots of great reviews on tire rack for their snow traction, etc and sounds like you had good luck with them whokilledthejams. But if the X would save even 2 mpgs that would be ~$142 per year or $1287 for the life of the tire (at $4 per gallon). Too bad there is so little info or reviews to go on.