I drive about 200 miles a week on highway. I noticed that after topping the cold air pressure to 42psi for all tires. My tires slowly go down to 40 at the end of the week. Well, left rear goes to 38 and always have 2psi difference with the other ones. I might have a nail in that one. I was driving my ML360 about the same distance every week. I don't remember that I had to top off every week. Is it something that I need to ask SC to look at? My wheels are in perfect shape, the pressure loss is so minimal I am not sure a bubble test would show anything, but at the end of the week they are lower.
Onur
Onur