Keep your valve stems clean! In order to keep your MORRFlate working evenly on all tires, it is extremely important to keep your valve stems clean! The valve core already restricts air flow so much... if there is ANY bit of dirt, sand, or debris in your valve stems (even 1 grain of sand!), then your MORRFlate 4 Tire Kit won't be able to evenly inflate or deflate your tires. But, at the same time, who wants to sit there and spend the time to unscrew and screw on your valve stem caps? Especially if it's raining, snowing, or just a really cold morning in Moab and your fingers don't want to work.