Onyx Vesper SS Rear ISO 6 Bolt Disc Hub
The Onyx Vesper SS is the Vesper with a dedicated single-speed driver, and it may be the best single-speed hub made: the sprag clutch engages the instant you stomp, with no dead stroke and no teeth to skip, and it is silent when you coast. Onyx machines and anodises it in Minnesota, with a short splined driver and spacers to set the chainline, centerlock or 6-bolt rotor mounts and Boost or standard spacing. This page covers the Onyx Vesper SS Rear ISO 6 Bolt Disc Hub.
The Vesper SS is built to order here. Choose the rim, spokes and nipples in the configurator; the wheel leaves Georgia laced, tensioned and trued.
Design and construction
The Vesper SS takes the light Vesper shell and fits a dedicated single-speed driver with a short splined body, machined and anodized in Minnesota. On a single speed the sprag clutch matters more than anywhere else: there is no derailleur to absorb a missed engagement, so the instant pickup is the difference between the drive arriving when you stand on it and a moment later.
Onyx catalogs more than twenty anodized colors, which on a deliberately simple bike is often the only color decision left to make.
How it rides
On a single speed there is no gear to spin up in; you stand and push, and a Vesper SS is there before the pedal has moved. Riders who switch from a pawl hub say the same thing: the bike feels connected. Coasting is silent and the hub is light.
Specifications
| Position | Rear |
|---|---|
| Axle options | QR 5x135mm Rear, Bolt On 10x135mm Rear, Thru Axle 12x135mm Rear, Thru Axle 12x142mm Rear |
| Driver bodies | 1 Single Speed Shimano HG Cassette (Aluminum) (+$45), 2 Single Speed Shimano HG Cassette (Steel) |
| Drillings | 28h, 32h |
| Spoke head | J-bend |
| Brake | 6-bolt disc |
| Left flange diameter | 60 mm |
| Right flange diameter | 60 mm |
| Left center-to-flange | 32.7 mm |
| Right center-to-flange | 19.5 mm |
| Spoke hole diameter | 2.6 mm |
| Weight | 403g |
| 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 |
Which version this is
Version notes. 6-bolt rotor mount, QR 5x135mm, Bolt On 10x135mm, Thru Axle 12x135mm, Thru Axle 12x142mm, 28h, 32h, about 403g, in baby blue pc, black ano, black aura pc, black matte ano, blu. If your frame or fork uses a different standard, the other versions of the Vesper single speed on this site cover it.
This is the 6-bolt Vesper single speed: the rotor bolts to a flange with six T25 bolts, which is the mount most mountain and gravel rotors still use and the easiest to find a rotor for on the road. If you run centerlock rotors, choose the centerlock version of the same hub instead.
Sizes, fit and compatibility
The Onyx Vesper SS Rear ISO 6 Bolt Disc Hub comes in the drillings listed on this page with the axle and rotor options shown in the configurator. The single-speed driver takes standard splined cogs with spacers to set the chainline. J-bend spokes in any gauge; we build most single-speed wheels with Sapim Race or Strong spokes or DT Competition and brass nipples.
It pairs naturally with any trail rim in the catalog that matches its drilling. Pick single speed as your bike type in the configurator and it recommends a spoke count and lacing pattern.
Put it in a custom wheel
Build a custom wheel around the Onyx Vesper SS Rear ISO 6 Bolt 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 gravel and road disc, track and road single-speed and MTB single-speed builds.
Onyx's testing and certifications
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.
Warranty and service: Onyx hubs carry a 5-year limited warranty to the original owner, non-transferable; the sprag clutch is guaranteed against manufacturing defects for one year, and Onyx wheel builds carry a 1-year limited warranty. The European distributor recommends "a seasonal check-up 2-3 times a year".
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 Vesper single speed; ProWheelBuilder is an independent custom wheel builder in Georgia and not the manufacturer. The build is the same every time: measured ERD, spokes cut to the half millimeter, staged tensioning with a gauge, stress relief, a final true, and tubeless tape and a valve on request.
The configurator shows only rims and spokes that fit the Vesper single speed drilling, strikes through combinations that are not made, and prices the wheel live.
Warranty
Onyx's warranty. Onyx Racing Products covers its hubs under a five-year limited warranty against defects in materials and workmanship.
ProWheelBuilder. Our one-year wheel warranty applies to any wheel we build around this part, alongside whatever the manufacturer offers. Inside that year, broken spokes are replaced no matter how they broke, and the wheel labor is ours - truing, re-tensioning or a full rebuild. A rim or hub failure that the maker covers, we claim for you and see through; one the maker declines, we answer with an eligible replacement at 25% off current retail. Shipping both ways is yours, and components you supply yourself fall outside this cover.
Full terms are on our Policies & Warranty page.
Vesper SS Rear ISO 6 Bolt Disc Hub questions
Will my rotors fit this hub?
This is the 6-bolt version: any ISO 6-bolt rotor bolts straight on with six T25 bolts, which is still the most common and the easiest rotor to replace anywhere. Centerlock rotors do not fit it - for those, take the centerlock version of the same hub, listed separately.
Which spokes and nipples suit the Vesper single speed?
For most riders a double-butted spoke such as Sapim Race or DT Competition with brass nipples; lighter riders can go to Sapim Laser or CX-Ray. The configurator recommends a gauge and count for the Vesper single speed from your bike type and weight.
How does a sprag clutch work?
A ring of tilting hardened-steel cams wedges against the race the instant you pedal and releases the instant you coast. There are no teeth, so engagement is instant and coasting is silent.
Vesper or Onyx Classic?
Vesper for cross-country, trail and enduro where weight matters; Classic for downhill, e-bikes and the heaviest duty, with more sprag rows.
Which drivers fit the Vesper?
Shimano HG, SRAM XD and Shimano Micro Spline, swappable on the common axle and selectable in the configurator.
Is the Vesper e-bike rated?
No. Onyx rates the Vesper for pedal bikes; the Onyx Classic is the e-bike and downhill hub.
Is ProWheelBuilder the manufacturer of the Onyx Vesper SS Rear ISO 6 Bolt Disc Hub?
We are not. Onyx manufactures the hub; ProWheelBuilder's part is the wheel: measuring, lacing, tensioning and truing it here in Georgia.
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.
