Harley air shocks are designed to be inflated to a specific pressure, depending on the model of motorcycle. For example, the 2017 Sportster models have a recommended psi range of 25-35. The 2017 Dyna models have a recommended psi range of 30-40. The 2017 Softail models have a recommended psi range of 35-45. Always refer to your owner's manual for the specific psi recommendations for your Harley air shocks.