Video: How an Onyx instant engagement hub works

Onyx Sprag Clutch, 432-Z 039661

Sprag Clutch – Onyx Racing Products uses sprag clutches in its rear bike hubs. Sprag clutches are unique because they engage instantly but operate silently. In addition, all sprag elements maintain gentle contact with the driver and hub body, gliding with minimal friction until torque is applied. Their unusual shape allows freewheeling in only one direction. When a rider pedals to induce torque, the sprags rock slightly to wedge between the hub and driver, giving Onyx hubs infinite points of engagement, always ready to go when you are. Since there are no teeth or spring-engaged pawls like those found in conventional ratchet mechanisms, Onyx hubs are almost noiseless during freewheeling.

Modular Freehub Unit (MFU) – The MFU design is standard on the Onyx Vesper hub line and Classic hub series. Rather than sharing the drive and axle loads in our freehub system, the drive and axle loads work independently. Two oversized bearings in the hub shell support the driver, which also actuates the sprag clutch engagement system. The freehub body interfaces with the driver but spins on a separate set of bearings. This design generates longer bearing life in the freehub and stiffens the rear axle assembly. MFU also makes adopting current and potential Freehub body standards easier for Onyx without replacing the clutch or driver assemblies.

Hyperglide Alloy Freehub – Onyx Hyperglide alloy freehub bodies are not like the rest. They feature steel inserts to combat gouging while saving weight over a steel freehub. The freehub itself is machined from 7075 aluminum alloy and utilizes steel pins to reinforce seven of the splines. This patented design enables cassette alignment using the two key slots and replaceable wear faces on the remaining slots. When worn out, the steel pins are replaceable by hand or with a set of pliers.

Ceramic Hybrid Bearings are standard on Onyx BMX Race hubs and Classic Hubs. Specially formulated for Onyx Racing Products bicycle hubs, these bearings feature ceramic (Si3N4) ball bearings and a hardened chrome steel race. Each bearing contains a heavy dual-lip seal for the outboard facing side and a lighter seal on the inboard side. A synthetic grease blend fill keeps these bearings spinning free and fast! Perfect for racing applications where every watt counts. Serviceable for long life.


Floating Axle – All Onyx rear hubs utilize a floating axle. This design separates drive forces from axle load under normal riding conditions. This approach further reduces drag when freewheeling and extends the bearing life of freehub bodies.