You can't just generically put a number on tire pressure. Well , you can but it will be wrong. Tire pressure in this application should be based on how you ride , how much weight you are carrying , and as Monk said , where you ride. I run 40 lbs in my Alpin. I'm a big guy and my wife isn't petite. Most if the time I'm riding 2 up. With myself and my wife my passenger weight is close to 500 lbs. The right tire pressure for that isn't going to be the same as a 175 pound guy. I get even tire wear at that pressure and it feels great solo or two up.