I seriously doubt anyone would outfit 7 bikes with dynamos! If one did, why not just swap the dynamo hub wheel between bikes thus you only need to buy one wheel with the dynamo, then buy several mounting brackets to fit the light so you can transfer the light from bike to bike. I mean really, who would spend all that money when it could be done for far less...I'm sure some people have more money than they could ever spend here so what else do they have to spend it on?