Parts of a Bike Fork – Labeled Diagram and Quiz

All 12 parts on the diagram

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A rigid fork 5

Steerer tube It goes up through the frame's head tube. The stem and handlebars clamp to it. Some fork makers call it the steer tube.
Crown race It is pressed on until it sits against the crown. The headset's lower bearing runs on it.
Crown It joins the two blades at the top. The steerer tube stands on it.
Fork blades One runs down each side of the front wheel. They taper toward the bottom.
Dropouts (fork ends) The ends of the front wheel's axle sit in the slots. They are also called fork ends.

A suspension fork 7

Lockout lever It locks the suspension, or nearly so, for smooth ground. Suspension is not wanted there. On some forks the lever is on the handlebar.
Stanchions They are fixed in the crown. The lowers slide up and down on them. They are also called upper tubes or inner legs.
Dust seals They keep water and dirt out of the fork. They wear, and are replaced in time.
Arch It joins the lowers' two sides, above the wheel. Some makers call it the brake arch.
Lowers (lower legs) They are the part joined to the axle. They slide on the stanchions as the fork works.
Brake mount A disc brake's caliper bolts to them.
Thru axle It passes through the wheel's hub and threads into the far leg. That clamps the hub between the two legs.

How this list was compiled: Part names checked on 2026-09-30; a name is kept only when two independent sources use it. (1) Wikipedia, text only: Bicycle fork, https://en.wikipedia.org/wiki/Bicycle_fork (two blades a fork crown joins at the top, steerer tube, fork ends, an arch joining the lowers' two sides, stanchions the lowers slide on, thru-axle, crown race); Bicycle suspension, https://en.wikipedia.org/wiki/Bicycle_suspension (stanchions and sliders, dust wipers and seals, lockout and its lever, brake mount). (2) A fork maker's suspension fork user manual, https://archive.org/details/manualzilla-id-6300715 (steerer tube, crown, crown race, upper tubes or stanchions, lower legs and lowers, dust seals, dropouts, thru axle, post style disc brake mount, lockout). (3) A second fork maker's suspension fork owner's manuals, https://archive.org/details/manualzilla-id-6734165 and https://archive.org/details/manualzilla-id-6004963 (steer tube, crown, crown race, stanchions or inner legs, outer legs, brake arch, dropouts, thru axle, seals, remote lockout lever). (4) A bicycle mechanic's reference site, its glossary, https://www.sheldonbrown.com/gloss_e-f.html and https://www.sheldonbrown.com/gloss_st-z.html (fork, fork crown, fork blades, fork end, steerer, dropout). (5) Two bicycle owner's manuals, https://archive.org/details/manualzilla-id-5719089 and https://archive.org/details/manualzilla-id-6982408 (fork blades, dropouts, steerer tube, crown), read for names only. Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; no maker's fork, nothing traced. Licence: own work

How it works

The parts of a bike fork hold the front wheel and let it steer. A rigid fork has two blades joined by a crown under a steerer tube. A suspension fork has sliding legs instead of blades.

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A rigid fork

The steerer tube stands on the crown, with the crown race at its foot. Two fork blades run down from the crown, one each side of the wheel, to the dropouts that hold the axle.

A suspension fork

Each leg is two tubes. The stanchions are fixed in the crown, and the lowers slide on them, with dust seals where the two meet. The arch joins the lowers. This fork has a lockout lever on top, a disc brake mount on one leg and a thru axle at the bottom.

Steerer tube, crown race and crown are asked on the rigid fork only; the suspension fork has them too.
Fork makers say steer tube, upper tubes and lower legs for steerer tube, stanchions and lowers.

Questions and answers

What are the parts of a bike fork?

A steerer tube, a crown and two legs with dropouts for the wheel's axle. On a rigid fork the legs are fork blades. On a suspension fork each leg is a stanchion and a lower, and an arch joins the two lowers.

What are stanchions on a bike fork?

The smooth upper tubes of a suspension fork. They are fixed in the crown, and the lower legs slide up and down on them.

What is the steerer tube?

The upright tube on top of the fork. It passes up through the frame, and the stem and handlebars are clamped to it, so turning the bars turns the fork.

What does the lockout do on a suspension fork?

It cuts the fork's travel right down, for more efficient riding on smooth ground. It is worked by a lever on the fork or, on some bikes, on the handlebar.