Overview “AC-2” = Dual Angular Contact. This describes the use of both angular contact bearings and angled bearing cups/hub bores used in the hub design. The AC-2 hub features revolutionary bearing installation and function never seen before in a bicycle hub. It has been designed from the ground up for ease of maintenance and optimal bearing performance. Here are a few key points of the AC-2 BMX Front Hub: -The AC-2 hubs use 20mm Angular Contact bearings with a wave spring pre-load. Bearings are pressed into tapered cups that mate with the angled bores machined into the hub shell. This design feature allows bearing/cup to be easily installed and removed from hub shell without any special tools. No more presses or hammers needed! Another attribute of the tapered bearing cup/angled hub shell bore design is how the bearings seat in the hub. The bearings/cups on each side of the hub shell are in perfect alignment with each other! This ensures superior bearing performance and less chance of premature wear. -Hub shell literally “floats” on the axle. The only force on the bearings is supplied by the wave spring(which delivers the appropriate bearing pre-load needed for angular contact bearings). Tightening of axle bolts has absolutely no affect on the bearings! -The bearings, wave spring, and shim(s) are secured on the axle by one retaining ring. The only tool used to assemble/disassemble the AC-2 hub is a pair of snap ring pliers! ###section### Product Specs AXLE SIZE: Female SPOKE HOLES: 36h BEARINGS: Angular contact WEIGHT: 245g (8.64oz) Colour: Red, Green, Blue, Matt Black, Gold, Black, Silver