Not all tire gauges read the same on the same set of tires The message there is to get a good tire gauge and use it ONLY on your car(don't loan it out either )and find which pressure works best on your car. I have ran several sets of M/T 315x60x15 on my car on the street and strip, 17 to 22 lbs on both uses. I try to remember to pump them up for crusing on the street to maybe 25 lbs, if I remember Don't expext those tires to last like a regular street tire If you can get 10,000 miles out of them on the street you will be doing great