A bicycle assembly can include a front or rear suspension system with a shock absorber. A front suspension system can be a suspension fork. A rear suspension system can include a rear shock absorber. The shock can have a shock body and a pressurized main air chamber within the shock body to act as an air spring. The shock can also have a valve configured to receive a pump for adding air to the main air chamber. A secondary air chamber and a control member can be used to reduce the pressure within the main air chamber by venting the secondary air chamber to the atmosphere.