Industry Nine Hydra 2 MTB Rear Centerlock Disc Hub
The Industry Nine Hydra 2 is the second generation of the hub that made instant engagement mainstream, and it fixes the things people complained about on the first one. It still has the phased six-pawl freehub, now on a 145-tooth steel drive ring for 870 points of engagement, which is 0.41 degrees of crank rotation before the wheel picks up. What changed is everything around it: a 65% thicker axle, deeper pawl pockets, a spacer between the shell and freehub that cuts shear loads roughly in half, bigger 6903 shell bearings with full-contact lip seals, and about 60% less coasting drag. Industry Nine machines and anodises it in Asheville, North Carolina, in every color it makes. This page covers the Industry Nine Hydra 2 MTB Rear Centerlock Disc Hub.
The Hydra 2 comes from us only as a finished wheel: pick the rim, spokes and nipples, and we lace, tension and true it by hand in Georgia before it ships.
Design and construction
Industry Nine's engagement trick is phasing: six pawls sit at slightly different angles so that only one or two engage at any instant, which multiplies the 145 teeth on the drive ring into 870 engagement points. The Hydra 2 keeps that and makes the parts around it bigger. The axle is much thicker than the original Hydra's, which was the part that flexed under big riders; the drive-side shell bearing grew, and the freehub now sits on a spacer that keeps it from loading the pawls sideways. The seals are full-contact lips that keep water out without the drag of the old design, and the freehub uses lighter spring pressure, which is where the 60% cut in coasting drag comes from.
The hubshell is machined from aluminum bar with J-bend flanges in 28 and 32 hole, anodized in Industry Nine's full color range, with centerlock or 6-bolt rotor mounts and end caps for Boost, Superboost and standard spacing. Freehubs swap between HG, XD and Micro Spline without tools.
How it rides
A Hydra 2 engages before you have finished thinking about it. On a technical climb or a trials-style move there is no dead stroke, and because the engagement is phased rather than a single huge ring, the pickup is smooth rather than harsh. The new hub coasts noticeably freer than the original and the freehub is quieter, though still unmistakably an Industry Nine.
We build the Hydra 2 for trail, enduro, downhill and e-bike wheels; the thicker axle and bigger bearings make it a better e-MTB hub than the original.
Specifications
| Position | Rear |
|---|---|
| Axle options | QR 5x141mm Boost Rear, Thru Axle 12x148mm Boost Rear, Thru Axle 12x150mm Rear, Thru Axle 12x157mm Super Boost Rear |
| Driver bodies | Shimano HG 8,9,10,11 & Road 12spd, SRAM XDR 10,11 & Road & MTB 12spd, Shimano Micro Spline 12spd |
| Drillings | 28h, 32h |
| Spoke head | J-bend |
| Brake | centerlock disc |
| Left flange diameter | 48 mm |
| Right flange diameter | 62 mm |
| Spoke hole diameter | 2.6 mm |
| Weight | 278g |
| Material | Aluminum |
| Finishes | black, blue, bronze, gold, green, lime green, orange, pink, purple, red, silver, turquoise |
About this listing
What sets this listing apart from the other Hydra 2 versions: centerlock rotor mount, QR 5x141mm Boost, Thru Axle 12x148mm Boost, Thru Axle 12x150mm, Thru Axle 12x157mm Super Boost, 28h, 32h drilling, about 278g, in black, blue, bronze, gold, green, lime green, orange, pink, . Pick the one that matches your frame and rotor and the rest of the hub is identical.
Centerlock is the lighter, quicker rotor mount: a splined rotor drops onto the hub and a single lockring holds it, so a rotor swap takes a minute with a lockring tool and there are no six small bolts to torque or lose. Shimano and most current road and gravel rotors are centerlock; 6-bolt rotors fit with an adapter.
Sizes, fit and compatibility
The Industry Nine Hydra 2 MTB Rear Centerlock Disc Hub comes in the drillings listed on this page with the axle, rotor and driver options shown in the configurator. J-bend spokes in any gauge; we build most Hydra 2 wheels with Sapim Race, D-Light or CX-Sprint spokes or DT Competition and brass nipples, and Industry Nine also sells a straight-pull version for its own alloy spokes.
It pairs naturally with Industry Nine's own Grade 300, Triad and Sector rims, and with Reserve, ENVE, We Are One, Nox, DT Swiss, Race Face and Stan's rims that match its drilling. Pick your bike type and weight in the configurator and it recommends a spoke count and lacing pattern.
Build it into a wheel
This hub is live in our Custom Wheel Program for mountain bike, fat bike and tandem and e-bike builds. Start a build with the Industry 9 Hydra 2 MTB Rear Centerlock Disc Hub and the configurator opens with this exact hub pinned at the top of the Industry Nine list — you choose the rest of the parts and it validates every combination as you go.
Testing, standards and warranty at Industry Nine
Industry Nine states it "has been anodizing & machining hubs, spokes, and drive systems in Asheville, NC since 2004" and that it engineers and manufactures every component of its hub and wheel systems in-house, including hub shells, axles, spokes and anodizing: "If it moves inside an I9 hub, we made it." Coverage of the Hydra2 launch (March 2025) reports Industry Nine drew on data from over 100,000 Hydra hubs in use to redesign the hub, with a 65% thicker axle "engineered for superior stress dissipation", larger 6903 bearings throughout, a labyrinth channel and full-contact radial lip seals against contamination. Industry Nine publishes no bearing-cycle, salt-spray, ISO 4210 or laboratory test figures for its hubs.
Warranty: Industry Nine states "Hubs are covered for five years against defects in materials and workmanship." Years 0-2 include parts, labor and return shipping; in years 3-5 parts are covered and labor and shipping may apply. Warranties apply to the original purchaser only with proof of purchase from a certified dealer; bearings and other normal wear items are excluded. Industry Nine says service needs only basic tools, "no proprietary tools are required".
Industry Nine's videos
Certifications
- Made in USA (Asheville, NC) — Industry Nine states hubs, spokes and drive systems have been anodized and machined in Asheville, NC since 2004; site tagline "HANDBUILT - ASHEVILLE, NC - KAMLOOPS, BC" (source)
- 5-year hub warranty — Parts, labor and return shipping years 0-2; parts only years 3-5; original purchaser; bearings excluded (source)
Sources on Industry Nine's site:
- About Industry Nine
- Industry Nine Warranty
- Industry Nine Hydra 2 Hubs (product page)
- Industry Nine Support Documents
- Industry Nine Hydra2 Support
Everything in this section is published by Industry Nine. ProWheelBuilder is the wheel builder, not the tester, and the hub reaches us as the maker ships it.
Building it at ProWheelBuilder
Industry Nine makes the Hydra 2 in Asheville, North Carolina; ProWheelBuilder is an independent custom wheel builder in Georgia and not the manufacturer. We measure the rim before we cut a spoke, bring the wheel up in three or four rounds with a gauge, stress-relieve it between rounds and true it last, then tape it and fit a valve if you want it tubeless.
Only compatible hubs and spokes appear in the configurator, impossible combinations are struck through rather than hidden, and the price is live.
Warranty
Industry Nine's warranty. Industry Nine covers its hubs against defects in materials and workmanship for five years from purchase, with two years on the anodized finish. Its alloy and carbon rims carry a lifetime defect warranty to the original purchaser, with parts, labor and return shipping covered for the first two years and parts thereafter. Bearing wear, impact and crash damage are not defects.
ProWheelBuilder. Any wheel we build on this part carries ProWheelBuilder's one-year warranty in addition to the manufacturer's. Broken spokes are replaced for a year whatever the cause, and all wheel-side labor is included - truing, re-tensioning, rebuilding. Where the maker covers a failed rim or hub we handle that claim for you; where they decline, an eligible replacement comes at 25% off current retail. The customer covers shipping in both directions. Components supplied by the customer are not covered.
Full terms are on our Policies & Warranty page.
Hydra 2 MTB Rear Centerlock Disc Hub questions
Will my rotors fit this hub?
This is the centerlock version, so a splined centerlock rotor drops on and a lockring holds it - one tool, no six bolts to torque or lose. If your rotors are 6-bolt they will fit with a centerlock adapter, or take the 6-bolt version of the same hub, which is a separate listing.
What changed from the Hydra to the Hydra 2?
A 65% thicker axle, bigger shell bearings with full-contact seals, deeper pawl pockets, a spacer that cuts freehub shear loads, engagement up from 690 to 870 points, and about 60% less coasting drag.
Is 870 points of engagement too much drag?
Not on the Hydra 2. Industry Nine cut spring pressure and improved the seals so it coasts freer than the original Hydra despite the higher engagement.
Which freehub bodies fit the Hydra 2?
Shimano HG, SRAM XD and Shimano Micro Spline, swappable without tools and selectable in the configurator.
Is the Hydra 2 e-bike rated?
Yes. The thicker axle and larger bearings were designed with e-MTB loads in mind; tell the configurator it is an e-bike and it picks the spokes.
Which axle spacing does it fit?
QR 5x141mm Boost Rear or Thru Axle 12x148mm Boost Rear or Thru Axle 12x150mm Rear or Thru Axle 12x157mm Super Boost Rear. Measure between the inside faces of your dropouts if you are unsure, or text us.
Does it need special spokes?
No. It takes standard J-bend spokes, which the configurator offers in every gauge and finish we stock.
Not sure? Text or leave a voicemail on 470-253-0929 or email info@prowheelbuilder.com — you will be talking to the people who build the wheels.
