Onyx Fat Bike Rear Centerlock Disc Hub
The Onyx fat bike hub brings the sprag clutch to fat-bike spacing: instant engagement with no teeth to skip between and total silence when coasting, in a hubshell spaced for 150mm front and 177 or 197mm rear thru-axles, with centerlock or 6-bolt rotor mounts, machined and anodized in Minnesota. A fat tire at 6 psi has so much grip that any dead stroke on a snow climb is lost momentum, and the Onyx has none. This page covers the Onyx Fat Bike Rear Centerlock Disc Hub.
The Onyx fat bike hub is not sold bare. You choose the rim and the rest of the build in the configurator, and it ships from our shop in Georgia laced, tensioned and trued by hand.
Design and construction
Fat-bike spacing asks a lot of a hub: 150mm at the front and 177 or 197mm at the rear puts the flanges a long way apart and the bearings under a wide, twisting load. Onyx machines the shell and anodises it in Minnesota for those widths, with centerlock or 6-bolt rotor mounts and the same sprag clutch as the rest of the range.
Silence is worth more in winter than anywhere else. A freehub packed with snow and grit is the one that starts skipping, and a clutch with no teeth has nothing to skip over.
How it rides
An Onyx fat hub engages the moment you push, which on snow and sand is the difference between cleaning a climb and walking it, and it coasts in silence through the woods. The labyrinth seal keeps slush and salt out and the hardened stainless driver shrugs off winter. It is the fat-bike hub for riders who want the best.
Specifications
| Position | Rear |
|---|---|
| Axle width | 170, 177, 190, 197 mm |
| Driver bodies | Shimano HG 8,9,10,11 & Road 12spd (Aluminum) (+$45), SRAM XD 10,11 & MTB 12spd (Aluminum) (+$45), Shimano Micro Spline 12spd (Aluminum) (+$45), Shimano HG 8,9,10,11 & Road 12spd (Steel), SRAM XD 10,11 & MTB 12spd (Steel), Shimano Micro Spline 12spd (Steel) |
| Drillings | 32h |
| Spoke head | J-bend |
| Brake | centerlock disc |
| Left flange diameter | 54 mm |
| Right flange diameter | 54 mm |
| Left center-to-flange | 47.4 mm |
| Right center-to-flange | 47.4 mm |
| Spoke hole diameter | 2.6 mm |
| Weight | 459g |
| Material | Aluminum |
| Finishes | baby blue pc, black ano, black aura pc, black matte ano, blue ano, blue candy pc, clear ano, gold ano, green ano, green anti freeze pc, green florescent pc, green kawasaki pc, orange ano, orange florescent pc, pink ano, pink florescent pc, purple ano, purple candy pc, red ano, red candy pc, turquoise ano, white pc, yellow cardinal pc, yellow florescent pc |
This listing
This is the centerlock version: the axle standards listed above, 32h drilling, about 459g, in baby blue pc, black ano, black aura pc, black matte ano, blu. Same internals and flanges as every other fat bike; only the mount and axle differ.
This is the centerlock fat bike: the rotor sits on a spline and a lockring holds it, which saves weight over six bolts and makes swapping rotors a one-tool job. If your rotors are 6-bolt, a centerlock adapter fits them, or choose the 6-bolt version of the same hub.
Sizes, fit and compatibility
The Onyx Fat Bike Rear Centerlock Disc Hub comes in the drillings listed on this page in 150mm front and 177 or 197mm rear thru-axle spacing with the rotor and driver options shown in the configurator. J-bend spokes in any gauge; we build most fat wheels with Sapim Race or DT Competition spokes and brass nipples.
It pairs with the HED Big Deal and Big Aluminum Deal, DT Swiss BR 710, Sun Ringle Mulefut and Surly fat rims in the catalog. Pick fat bike as your bike type in the configurator and it recommends a spoke count and lacing pattern for the offset.
Put it in a custom wheel
Build a custom wheel around the Onyx Fat Bike Rear Centerlock Disc Hub — the link drops you into our Custom Wheel Program with this hub pinned, ready for you to choose the rest. It is set up for fat bike builds.
What Onyx says about testing
Onyx Racing Products hubs are made in the USA by a division of Christianson Systems in Minnesota; in a 2020 interview the company described itself as "Minnesota made and owned". Hub shells are machined from 7075 aluminum (retailer listings cite 7075-T651 with heat-treated stainless steel and titanium hardware), and Onyx's European distributor states Onyx freehub units "are made out of high-grade 7075 aerospace-grade aluminum in the USA". Bearings are hybrid ceramic on the Classic line and an upgrade option on Vesper; the distributor states "Since early 2025 all Onyx hubs have been assembled with high-quality Japanese EZO bearings." Onyx specifies a grease service temperature range of -58°F (-50°C) to 248°F (120°C). It publishes no bearing-cycle, salt-spray, ISO 4210 or load-test figures. Onyx's specifications state radial lacing is not permitted on any Onyx hub and set a maximum spoke tension of 120 KgF.
the patented sprag clutch is a one-way clutch of cams between two races, giving instant engagement, instant disengagement when coasting and silent operation; BMX hubs use a single-row sprag assembly, mountain, road and gravel hubs a double-row assembly. Onyx publishes no numerical torque capacity; its distributor states Classic hubs "are e-bike approved for bikes that have a mid-drive unit with a peak power output of up to 1500W."
Onyx's videos
Inside the Onyx shop
Certifications
- Made in USA (Minnesota) — Onyx states it is "Minnesota made and owned"; retailer and distributor listings state "Made in the USA" (source)
- 5-year limited hub warranty — Hub 5 years to original owner; sprag clutch 1 year against manufacturing defects; wheel builds 1 year (source)
- E-bike approval (Classic hubs) — Distributor states Classic hubs are e-bike approved for mid-drive units with peak power output up to 1500W (source)
Sources on Onyx's site:
- Onyx Racing Products - Tech (site returned 403 at time of research)
- Onyx Racing Products - Limited Warranty (U.S. Only)
- Onyx Racing Products Wheels - Warranty
- November Bicycles: In their own words - Onyx Racing Products (April 17, 2020)
- Onyx Hubs Europe - Technology
Onyx publishes those results; ProWheelBuilder builds the hub into a wheel and does not test it in a lab.
Building it at ProWheelBuilder
Onyx makes the fat bike; ProWheelBuilder is an independent custom wheel builder in Georgia and not the manufacturer. Every fat bike wheel we build gets spokes cut from the measured ERD of the rim, staged tensioning with a gauge, stress relief and a final true before it ships.
In the configurator you will only see parts that fit this drilling; combinations that are not made are struck through, and the price updates as you pick.
Warranty
Onyx's warranty. Onyx Racing Products covers its hubs under a five-year limited warranty against defects in materials and workmanship.
ProWheelBuilder. Built into a wheel by us, this part is covered by our own one-year wheel warranty on top of the maker's. For a year we replace broken spokes whatever caused them, and we cover the labor on the wheel - truing, re-tensioning, a rebuild if it needs one. If a rim or hub fails and its maker covers it, we run that claim for you; if the maker says no, you get an eligible replacement rim or hub at 25% off retail. You pay the shipping each way. Wheels built from parts you send us are excluded.
Full terms are on our Policies & Warranty page.
Fat Bike 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 spacing is the Onyx fat bike hub?
150 x 15mm front and 177 or 197 x 12mm rear, selectable in the configurator.
Is the Onyx fat hub good for winter?
Yes. The labyrinth seal and hardened stainless driver handle slush and salt; a clean and regrease each spring keeps it happy.
Which drivers fit?
Shimano HG, SRAM XD and Shimano Micro Spline, selectable in the configurator.
Is it silent like other Onyx hubs?
Yes. The sprag clutch has no teeth, so coasting is completely silent.
Which axle spacing does it fit?
170, 177, 190, 197 mm. 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.
