Why is it that we spend a fortune on our bikes but then make them sound like they have a soda can wedged between the frame and tire? For some reason, loud hubs have become cool, and so synonymous with quality that nine times out of ten you can guess who spent the most on their bike just by hearing them coast across the trailhead parking lot.
It's true: Some of the loudest hubs on the market are also the highest quality. It probably started with Chris King's hubs, which are well-made and last forever, but create a sound so intolerable that the only way they'd sell is with a marketing campaign around the sound itself: Loud equals good. Also, people like hubs with fast engagement, which usually makes them louder–more pawls running over more teeth make more noise.
You could opt for quieter hubs with slightly less engagement if you don't ride super-technical trails where quick-ratcheting hubs add a huge advantage. Or you could get an Onyx hub, which is not only completely silent, but also engages instantly. Yes, instantly.
To make this possible, Onyx uses a sprag clutch instead of traditional pawls. A sprag clutch looks like a roller bearing with non-rotating, figure eight-shaped sprags that, when turned the opposite way, instantly tilt and lock. Sprag clutches are used on helicopter rotors, car transmissions and other insanely high-load applications. They work.
The $445 Onyx hub has two rows of sprags to ensure solid engagement. I've never been able to make the thing slip and I've had it completely submerged in river crossings, blasted by fine desert sand and everything in between. The bearings–there are four of them, one in the driver and three in the hubshell–are still running as smoothly as the day I built the wheels last September.
I don't know if it's because the hub makes absolutely no noise, or because it has basically zero drag, but it feels incredibly fast. Until you ride this silky-smooth masterpiece, you don't realize how tactile the loud ratcheting sound of other hubs is–as if you can actually feel the vibrations through the bike. The Onyx hub feels like the epitome of precision, and it makes other hubs seem unrefined in comparison.
Downsides? At 450 grams, it's the heaviest high-end hub around. Also, the power transfer feels almost rubbery in comparison to a pawled hub. It feels like riding a belt-drive bike–it's smooth and firm, but a touch vague. Actually, I'd hesitate to call this a downside, but it's worth mentioning. Onyx flips the widespread correlation between noise and engagement on its back, gives a middle finger to loud hubs, and does it all without a hint of drag.