What is the deal with presta tubes in mountain bike tires? I have used at least three pairs and I've had problems with leaks. They are Kenda tubes, too. The last one doesn't inflate properly. It says that a 1.95" tire is in the range, but when I pump it and go to 165 pounds of pressure, which is well above the recommended of 80, the tire is still not tight. I can't figure it out. I think I will just stick with Schrader tubes in the future on the mountain bikes. Will hybrid rims fit Schrader valves? If so, maybe I will replace those down the road when the current tubes go bad on my hybrid.