If you have trouble with chronically leaking tires and nothing seems to help, check your valve stems and cores! Low-quality cores can stick open. Sometimes they just don't close properly to begin with. Either way, you're stuck scratching your head and constantly filling your tires. New valve stem cores are cheap insurance against preventable leaks.
Our valve stem cores fit most standard (not extended length) valve stems, including our Metal Tire Valve Stem (Part No. 3334). Sold individually.