Use a 25mm axle in a 50mm opening.
Converter Bush (25mm to 50mm)
This converter bush allows you to use a smaller diameter axle (25mm) in a larger opening (50mm). This can also be used as a 5cm spacer on a 25mm axle to move your wheels further out along the axle. This bush is nearly indestructible.
|Outside Diameter||46.5 mm|
|Opening||Designed for 50 mm opening|
|Inside Diameter||25 mm|