Am I the only one who has trouble checking the rear tire pressure on my ST13? I have several tire gauges and none of them seem to be able to get a good reading since the valve stem is so close to the wheel. I'm losing pressure and I can't find any nails or anything else so I'm guessing that I have a bad valve stem or valve stem core. I have a brand new 45 degree valve stem left over from my Concours days that I'm going to have installed. The tire is almost brand new so I really don't want to replace it unless I have no choice. Also I really want to change over to the Michelins when this Dunlop Sportmax set starts to wear out. I've read two opposing reviews. One reviewer stated that the PR3 gave him better traction than the PR4 and one said the opposite. Does anyone have any suggestions or experience with the Michelins? Also, has anyone tried a Michelin on the rear and a Dunlop on the front? I've never mixed tires like that but I've seen others get away with it. I'm a little leery about breaking down a nearly new tire but I've done it before with no problem, although that was with a spoke wheel and tube.