Onyx hubs are known for their instant engagement, thanks to a Sprag clutch system that expands metal pins between two steel rings to engage. Because the pins are basically dragging on the rings’ surfaces, they rock into a locked position within a fraction of a degree of rotation, which is virtually imperceptible. The downside is they’re heavy – that’s a lot of steel, and they need two rows of the clutch to handle the torque, especially for mountain biking.
Now, they’re working on a new design that has a lighter Sprag clutch system inside, using one full clutch with a half clutch behind it, rather than the usual full dual clutch. Shown above, the full dual clutch is on the right in the see-thru hub shell. A version of the 1.5 clutch is on the left in the cutaway, shown in a road version that’s slightly different than what will end up in the new hubs… which get both the Centerlock and 6-bolt brake mount options.
They can’t use just one clutch because it won’t have a high enough torque value. As mentioned, the clutch has to be backed by a steel sleeve on both sides, so reducing the size of it reduced weight quite a bit. The target weight for the new design on a 142×12 is 320g. Their current hub is 414g, so it’s a big drop.
They’re working on a 148×12 (Boost) model, too. No ETA yet, but it’ll also get a new end cap system that makes it easier to swap. Why not Boost to start? Because the original idea was to use it for cyclocross, and they literally just started working on this prototype a few weeks before coming to Interbike.
If you just can’t wait for those new designs, which are at least 6-9 months out, you can swap in their new alloy freehub body, which comes in 70g lighter. It’s a pinned design that slides steel u-shaped pins into the alloy body, to prevent the cassette from biting into the softer aluminum. As they wear, you can slide them out and flip them over, doubling their life, or just replace them.
All of their hubs come stock with ceramic hybrid bearings (ceramic ball, steel race), and now you can even get them with a Campagnolo freehub body.