FRONT SPROCKET: 4059 K teeth number : 17 16CrNi4 Steel REAR SPROCKET: 2104 C teeth number: 38 Rear sprocket C45 steel CHAIN: 525GXW plates number: 116 The leading edge XW-Ring seal is made of an advanced nitrile butadiene composite and features six contact lips and two convex inner/outer stabilizers. This means four lubrication pools to protect against high-speed abrasion, heat build up, torsional flex and the loss of lubricant under these extreme conditions. As a result GWX chains provide the user with 10 times longer wearlife compared to standard chains