Onyx MTB Front ISO 6 Bolt Disc Hub
This page covers the Onyx MTB Front ISO 6 Bolt Disc Hub.
The Onyx Classic 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
Machined and anodized in Minnesota, it is the hub to choose when the loads are high rather than when the grams matter.
Because the front Classic has no freehub, it is the hub that asks for the least: a spin of the axle to check the bearings once a season and nothing else. The flanges, bearings and seals are the same as the rear's, the axle converts between the front standards with end caps, and the rotor mounts the same way. Choose it to match a rear of the same model, or on its own for a fork that needs a new front wheel.
How it rides
For cross-country, trail and enduro the Vesper is lighter; for downhill, park and e-MTBs, the Classic is the Onyx hub we recommend.
A front wheel is where you feel a hub least and a build most. With no drive torque to carry, the front Classic can be laced two-cross or even radial on the non-rotor side on a rim-brake bike, which makes a lighter, more direct-feeling wheel; on a disc bike we lace both sides crossed so the rotor's braking torque has spokes to pull against. Either way the front wheel is the one that steers, and a stiff, true front wheel is most of what makes a bike feel precise.
Specifications
| Position | Front |
|---|---|
| Axle options | QR 5x100mm Front, Thru Axle 12x100mm Front, Thru Axle 15x100mm Front, Thru Axle 15x110mm Boost Front, Thru Axle 20x110mm Boost Front |
| Drillings | 24h, 28h, 32h, 36h |
| Spoke head | J-bend |
| Brake | 6-bolt disc |
| Left flange diameter | 57 mm |
| Right flange diameter | 57 mm |
| Spoke hole diameter | 2.6 mm |
| Weight | 213g |
| 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 5x100mm, Thru Axle 12x100mm, Thru Axle 15x100mm, Thru Axle 15x110mm Boost and more, 24h, 28h, 32h, 36h, about 213g, 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 Classic on this site cover it.
Six-bolt is the original disc mount and still the most universal: any ISO 6-bolt rotor from any brand bolts straight on, rotors are cheap and easy to find anywhere, and the six-bolt flange is a robust, simple interface that has been on mountain bikes for twenty-five years. Centerlock rotors do not fit it.
Sizes, fit and compatibility
J-bend spokes in any gauge; we build most Classic wheels with Sapim Race, Strong or CX-Sprint spokes or DT Competition and Alpine III and brass nipples.
It pairs naturally with the WTB HTZ, DT Swiss FR 541 and HX 531, Race Face ARC Heavy Duty, Stan's Flow EX3 and the carbon gravity rims in the catalog. Pick downhill or e-bike as your bike type in the configurator and it recommends a spoke count and lacing pattern.
Build it with us
We build this hub to order. Open the Custom Wheel Program with the Onyx MTB Front ISO 6 Bolt Disc Hub already selected and pick the parts around it; it is offered for gravel and road disc, track and road single-speed, mountain bike, MTB single-speed and fat bike builds, and the configurator will not let you assemble a combination we would not build.
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". 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 European distributor recommends "a seasonal check-up 2-3 times a year".
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 Classic; 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 Classic 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. 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.
MTB Front 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.
Classic or Vesper?
Classic for downhill, e-bikes and the heaviest duty; Vesper for cross-country, trail and enduro where its 23% lower weight matters.
Is ProWheelBuilder the manufacturer of the Onyx MTB Front 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.
Which axle spacing does it fit?
QR 5x100mm Front or Thru Axle 12x100mm Front or Thru Axle 15x100mm Front or Thru Axle 15x110mm Boost Front or Thru Axle 20x110mm Boost Front. 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.
How long will the wheel take?
Build time comes down to parts availability rather than bench time. The estimated ship date is shown in the configurator before you check out.
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.
