Wrote to Michelin regarding load pressure for LT275/70R18 M/S2
tires (http://www.tundratalk.net/forums/#)....

Got this back.

Quote:


Hello ____ (me),


Thank you for your email. We welcome the opportunity to serve you.



You can use the following information for load/pressure for a LT275/70R18 LRE tire.



35 40 45 50 55 60 65 70 75 80

2070 2270 2470 2680 2840 3020 3195 3360 3530 3640

We appreciate your business and thank you for choosing Michelin.

It is our goal to ensure that your issue has been resolved or your question answered to your satisfaction. If we can assist you further, please respond to this email or call us at 1-800-642-4354 (toll free) between 8:00AM and 8:00PM Eastern Time Monday through Friday or between 8:30AM and 4:30PM Eastern Time on Saturday.

Sincerely,

Consumer Care Department
Certified Michelin Product Expert



So, it seems that running 50 psi is a little overkill for daily
driving (http://www.tundratalk.net/forums/#).