Cockpit Accessories

BMX cockpit accessories: the small hardware that holds it all together

A headset is not adjusted with the stem, but with a top cap, a bolt and an anchor point inside the steerer. These are the parts most often forgotten at build time or lost after a crash, and they decide whether the steering stays play-free all season or starts knocking from the second moto.

Headset top caps and preload bolts

The top cap and its bolt, usually M6, exist only to compress the stack — spacers, stem, bearings — while you set the adjustment. Once preload is achieved, it is the stem bolts that actually lock the assembly onto the steerer. CNC-machined anodised alloy caps replace the plastic ones supplied as standard and let you match the colour to the frame.

Star nuts and steerer expanders

The cap bolt has to thread into something. On a steel or aluminium steerer, a star nut is driven a few centimetres below the top. On a carbon steerer a star nut is out of the question: you need a cone or expanding-collar expander that grips without marking the wall. Always check the steerer material of your BMX forks before ordering.

Stem hardware and small parts

• M5 and M6 stem clamp bolts, hex or torx, in stainless steel, 7075 aluminium or titanium
• Head tube covers and conical compression rings for integrated headsets
• Replacement dust covers and seals for semi-integrated cups
• Shims to clamp a 22.2 mm bar in a stem designed for 25.4 mm
• Coloured bolt kits to match stem, seat clamp and steering limiter

Checking dimensions before ordering

Three figures are usually enough: the 1"1/8 (28.6 mm) steerer, the 22.2 mm bar clamp and the thread of the top cap bolt. Stem bolts are replaced like for like in length: one that is too long bottoms out in the stem body and gives a false torque reading, one that is too short does not engage enough thread. Respect the torque figures given by the maker of the stem — aluminium and titanium do not forgive over-tightening.

Compatibility with the rest of the cockpit

A top cap only works if the stem stands two to three millimetres proud of the top of the steerer: that is the job of the headset spacers. The conical ring is specific to the model of headset and is not interchangeable between brands. Shims, finally, only work from 22.2 up to 25.4 mm, never the other way round.

When to replace these parts

Change a bolt whose head is starting to round off, a split dust cover that lets track dirt in, a star nut that spins in the steerer, and as a matter of course any hardware that has taken a frontal impact. These parts cost little and save a full strip-down in the middle of a race weekend.

The BMX RACING advice

Give us the headset brand, the steerer material and the stem model: we identify the exact reference rather than selling you an approximate kit. Dispatched within 24 to 72 hours and you can spread the cost over 2 or 3 payments with Alma.