Your tires will arrive inflated and ready to ride, but always check tire pressure before hitting the road. Your VOLT has a maximum inflation of 70 PSI - this means pounds per square inch and we recommend checking this with a pressure gauge, which can be found on an air pump. We recommend checking your tire pressure often. If you need to add air to your tires, the VOLT tires can be filled with a bicycle hand pump, which you can find at most bike shops or sporting goods stores. Safely inflated tires should feel firm and slightly compressible between your thumb and index finger when squeezed.