True story: way back in the when I was a Inspection mechanic in the great Commonwealth of Pa. I had a feller bring his Dodge truck in and I had it on the lift , doing the usual "State Inspection, Emissions, oils change, rotate tires..." etc.etc. The guy was a talkative feller, hanging around the back of the garage bay watching me put his truck up, pull the wheels etc. it came time for the tire rotation, he said " see those green caps? you don't need to add air, they have hydrogen in 'em, its what they run at NASCAR..." without missing a beat and like the typical smart azz I was at the time i said "Oh yeah, well this isn't a race truck..." I realized I shouldn't have said it, but it was too late...:)
