All three models of the Stages Indoor Cycling bike models feature Gates® Carbon Drive™ carbon fiber belts. These belts are significantly quieter than traditional chain driven bikes, especially when in a classroom setting, where they are similar to a low conversational volume while being ridden at all speeds. Under normal use, a single bike puts out around 50-55 dB, which is can be compared to the noise level of rainfall or quiet conversation, but is slightly quieter than normal conversation volume.