Quality deep groove ball bearings made in Japan NTN Bearings specialists. These ball bearings are suitable depending on the design for various uses on scooters, motorcycles or quads/ ATVs. For example, as wheel bearings, gear bearings, motor bearings or bearings for chassis and frame. Inside diameter (mm): 17 outer diameter (mm): 40 thickness / depth (mm): 12 clearance: C4 embodiment: open on both sides. In addition these bearings are used as crankshaft bearings on Puch Maxi and Puch Maxi P1.