Tires have been known to lose up to 1psi (pounds per square inch) every month, so check all tires, including your spare, once a month (or before a long trip). It’s easy. Here’s how:
Most tires are filled with compressed air. But some tire retailers have started to put nitrogen into their customers’ tires. (Nitrogen is simply dry air with the oxygen removed. Air contains nearly 79% nitrogen already.) Because nitrogen replaces oxygen, less air can escape your tires, and your inflation pressure stays higher longer. Unfortunately, there are other possible sources of leaks (tire/rim interface, valve, valve/rim interface and the wheel) which prevent the guarantee of pressure maintenance for individuals using air or nitrogen inflation.
Nitrogen and compressed air CAN be mixed, if needed. Tires manufactured by Michelin are designed to deliver their expected performance when inflated with air or nitrogen, as long as the user respects the pressures recommended by the vehicle manufacturer on the vehicle’s placard or by the tire manufacturer.