fatvegan

One or both of the wheels will have a spoke that looks different to the others. It will be a tube built into the spoke and the tube contains a lug with a spring to keep it in place. The lug holds the wheel onto the axle. You can create a hole in the plastic cylinder so you can manually slide the lug away from the axle. The hole needs to be a reasonable size to be able to move the lug far enough but you don't want to destroy the cylinder. Depending on the state of the mechanism you may just be able to put the wheel back by hitting the centre with a hammer. But the spring mechanism will probably need to be in tact for the lug to stay in place.