To make our most advanced trail, enduro, E-bike, and DH hub even better, we put durability at the forefront, systematically eliminating potential failure points using data gleaned from the 100,000+ Hydra hubs in use around the world.

The result is a hub that can shrug off extreme use by the most demanding riders. Here’s how we achieved it:

A 65% thicker axle that’s been redesigned to dissipate stress more effectively.
Larger 6903 bearings throughout, and a new labyrinth channel and full-contact radial lip seal to keep out elements that cause premature bearing wear.
A new, foolproof design to ensure consistent bearing preload, regardless of variations in axle tightness.
Larger, 5.5mm pawl pockets that dissipate force 26% better, preventing stretching and elongation of the pockets over years of use.
Tougher metal for the drivering and an extra tooth on each pawl, guaranteeing Hydra2 can easily handle the torque of the most powerful ebike motors.

In our effort to make the Hydra2 hub bomb-proof, bullet-proof, and Brandon-proof, we didn’t compromise on meaningful performance gains, and the next generation has both quicker 0.41° engagement and 60% less coasting drag than its predecessor.

Combine I9’s trademark direct thread hubshell and machined aluminum spokes, and you’ve got a hub system with brains, brawn, and beauty — a piece of rideable art built by some of the most innovative engineering minds in the cycling industry.

For the next generation of riders, bikes, and trails that demand the very best, Hydra2 is the pinnacle of hub performance.

Technical specifications

Weight - 157g
Spoke Holes - 28 or 32

Frequently asked questions

Which end caps do I need, and are they included?

They’re included and we fit them before it ships – no extra cost, nothing else to buy. Add the hub to your cart and tell us your fork in the order comments, and it arrives ready to build. If you’re not certain what your fork takes, give us the model and we’ll work it out.

Worth knowing, because most overseas listings sell end caps as a separate kit. The three options are 15×110 Boost, 15×110 Torque Cap, or 20×110 Boost. Torque Caps suit RockShox forks with the wider 31mm inset crown, and they only fit 6-bolt hubs like this one.

If I change forks later, do I need a new hub?

No – this is the main reason to buy a hub like this rather than a cheap one. The end caps pull off and push on, so moving between 15×110, Torque Cap and 20×110 is a small part and a few minutes’ work, not a new wheel. The hub shell, bearings and spokes stay exactly as they are.

Buy it for the fork you’re running now rather than paying for options you may never use. If you change forks down the track, bring the wheel in and we’ll swap the caps.

Should I choose 28 or 32 hole?

Let the rim decide, and don’t assume more spokes is automatically better. Plenty of enduro wheelsets are specced 28 hole on purpose – a slightly more compliant wheel tracks better and finds more grip on rough ground than a stiffer one does.

Follow the rim manufacturer’s guidance for the rim you’re building onto; they’ve tested it. If you’re replacing a hub in an existing wheel, match what your rim already has. Tell us the rim and we’ll confirm before you order.

Can I build this with normal spokes?

Yes. This is the Classic hub, which takes standard J-bend steel spokes with scalloped flanges – so any decent spoke will do and you’re not tied to Industry Nine’s proprietary alloy ones. That’s the difference between these and I9’s System wheels, which is where most of the confusion comes from.

We build wheels in-house, so if you’d like it laced to a rim, tell us the rim and spoke count and we’ll quote the build with it.