cnc machined one piece rocker einteilig gefräster 3D Umlenkhebel quadruple sealed industrial ball bearings 4fach gedichtete Industrie- Kugellager rado dropout with Maxle Axle RADO Ausfallende mit Maxle Achse PM180 142x12mm Maxle Axle Postmount 142x12mm Maxle ET-Key