Does anyone know how the hubs are attached on the Alsport trikes? The setup I have is a 5 on 4 1/2 bolt pattern hub on a differential axle. The end of the hub appears to be fitted with a cap, but I was unable to persuade it to come off if it is a cap. I didn't want to go overboard, just in case it isn't how the hubs come off. Any help on this would be greatly appreciated.