So in the trunk lid example, the energy that helps raise the lid was stored in the spring from the last time you shut the lid. The gas spring provides resistanc

So in the trunk lid example, the energy that helps raise the lid was stored in the spring from the last time you shut the lid. The gas spring provides resistance on the closure, and assistance on the opening. With this wheel, the energy that goes into compressing the 12 o'clock spring must be provided (partially!) from the expanding 6 o'clock spring, plus additional energy from the cyclist to cover the mechanical losses in the system. I don't see any left over energy that can be used to help with forward propulsion. Maybe on very rough terrain it helps out by trading forward velocity with assistance up a bump, then trading the gravity on the other side of the bump to push forward again. But that's a far cry from the claims being made on the page.