BMX Part
Front Hub
A front hub is the centre of a BMX front wheel, holding the axle and bearings that let the wheel spin inside the fork dropouts.
Updated 3 min read569 words
A front hub is the centre of the front wheel. It holds the axle and bearings that let the wheel spin between the fork dropouts. On a BMX it also takes the impact of landings and the strain of grinds, so axle size and bearing quality matter.
What it does
The hub shell holds the spoke holes. The spokes connect the hub to the rim. An axle runs through the middle of the shell on two bearings, and the ends of the axle clamp into the dropouts of the forks.
A front hub is simpler than a rear hub. It has no driver or clutch. Its main job is to spin smoothly and survive hits.
Types and standards
Axle size
| Axle | Notes |
|---|---|
| 3/8 inch (about 9.5mm) | Common on entry level bikes. Lighter and more likely to bend. |
| 10mm | A mid-range choice. Used by many freestyle front hubs. |
| 14mm | The strongest option. Often paired with a female axle. |
Axle style: male or female
| Style | How it works | Notes |
|---|---|---|
| Male | The axle ends are threaded and stick out. Nuts hold the wheel in the fork. | Simple and common. Many hub guards clamp over the nut. |
| Female | The axle is hollow with an internal thread. Bolts screw into each end. | Neater, with no protruding threads. Needs hex bolts. |
Bolt or nut
Hubs with a bolt-on (female) axle use a hex key. Nut-on hubs use a spanner or socket. Both hold the wheel in place, so pick on compatibility and preference. Bolts sit tidier against the fork. Nuts leave a threaded end exposed, but many guards are designed around them.
Spoke count
Front hubs are usually drilled for 36 spokes. Match the hub to the rim.
Sizing and compatibility
- Spacing: BMX front hubs fit 100mm dropout spacing.
- Axle diameter: The dropouts on the forks must fit your axle. Forks are built for a particular axle size, and some only take 3/8 inch or 10mm. An axle thicker than the slot will not fit, so check your fork maker's spec.
- Spoke count: Match your rim.
- Hub guards: The hub guards must match your axle thread or bolt. Guards made for a 14mm axle will not fit a 3/8 inch axle.
- Brake mounts: If you run a front brake, see brakes. The rim needs a brake surface.
How to choose
- Check your fork dropout slot first. That decides the maximum axle size.
- Pick 14mm if your forks allow it and you ride hard.
- Choose male if you want simple compatibility with common guards. Choose female if you prefer a clean finish.
- Look for sealed bearings. They roll smoothly and last longer in the wet.
- Keep the front hub matched in style to your rear hub so you can use the same tools and guards.
Front hubs are generally cheaper than rear hubs. Quality versions cost more but are still a modest part of a build. See how to build a BMX bike from parts for budget guidance.
Maintenance
- Check the axle nuts or bolts are tight every few rides. A loose axle damages dropouts.
- Spin the wheel with the bike held up. If it feels rough or loose, the bearings need attention.
- Clean and re-grease or replace the bearings when they feel gritty.
- Keep an eye on the axle for bends. A bent axle should be replaced right away.
- See BMX maintenance basics.
Related parts
Forks, hub guards, rims, cassette hub, freecoaster hub and brakes.
Frequently asked questions about Front Hub
What axle size do I need?
It must match your fork dropouts and your hub guards. Check the dropout slot or the fork maker's spec before you buy.
Is a 14mm front axle better?
It is stronger and stiffer than a 10mm axle, so it suits hard riding. Check that your forks have a slot wide enough for it.
Do I need a female axle?
Not necessarily. Female axles give a cleaner finish. Male axles work well and suit many hub guards. Pick the one that matches your forks and guards.
Watch on the LUXBMX YouTube
A video about Front Hub from the LUXBMX YouTube channel.
Shop at LUXBMX
Popular picks for this article from LUXBMX, an Australian BMX store.
Colony Wasp Front HubView the Colony Wasp Front Hub at LUXBMX
Profile Mini Front HubView the Profile Mini Front Hub at LUXBMX
Onyx BMX 100/20mm Thru-bolt Solid Front HubView the Onyx BMX 100/20mm Thru-bolt Solid Front Hub at LUXBMX
Photos: LUXBMX
BMX Wiki and LUXBMX share an owner. Links to the store are not paid placements and do not change what articles say. About this relationship
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