I've had a Tubliss front tube fail. The tube is stressed at the valve stem due to the nut required on the stem. They provide a rubber washer that protects the tube from the nut, but the nut and washer hold the tube elevated from the rim. The tube has to stretch down to contact the rim and this creates a stress point. The failure spot is about 1/4" long, right near the base of the valve stem. After having the front fail, I checked my rear Tubliss and the tube had the same failure developing (it just hadn't burst yet). These tubes were in service for more than a year. The tube would have a better fit if the valve stem nut was removed; however the tube has no reinforcement at the stem base. The brass stem is the same diameter over it's full length and only has some grooves to grip the rubber. If the nut is removed the high pressure will extrude the stem out of the tube. I beveled the valve stem hole inside the rim and gave the nut a matching bevel. This lets the nut sit closer to the rim so there is less stretching of the tube. I installed new Gen2 Tubliss systems front and rear. The Gen 2 inner tube is supposed to be thicker than the original, but I didn't notice any significant change in thickness.