Valve Caps

BMX race valve caps: small part, real job

On a BMX race bike the valve takes everything the track throws at it: wet soil at the foot of the hill, gate dust, a pressure washer at the end of the day. The valve cap keeps that mechanism clean and stops a grain of grit sitting on the core seat just as you top up the pressure between motos. It also protects the thread, which is fragile on long Presta valves.

Presta or Schrader: identifying your valve

Two standards coexist in BMX. The Presta valve is slim, with a small knurled nut you undo before inflating, and it equips most 20" and 24" race tubes. The Schrader valve is wider, the same fitting as a car tyre, and turns up on the original tubes of many complete bikes and on training wheels. Caps are not interchangeable: the threads differ.

• Presta: fine thread, narrow cap, often with an O-ring
• Schrader: coarse thread, shorter and fatter cap
• Sold in pairs, so both wheels are covered

Aluminium, plastic or brass

The plastic cap supplied with the tube does the job, weighs nothing and never seizes. A CNC-machined anodised aluminium cap gives a knurled grip that is far easier to use with cold or muddy hands, and lets you match the colour to the rest of the build. Some models include a seal that limits water ingress. Brass, heavier, is mostly found on the original caps of Schrader valves.

Avoiding a seized cap

This is the one genuine watch point in the category. An aluminium cap done up hard on an aluminium valve can seize over time, especially after a winter of wet sessions. Always tighten by hand, never force it, and unscrew it now and then to check it still turns freely. If the bike lives outdoors or you ride near the coast, a plastic cap remains the safest choice.

Matching without adding weight

Anodised caps come in the same colours as clamps, pads and plates, which makes them the cheapest way to finish a matching build. Riders counting every gram stick to plastic, but the difference is only a few grams either way. Coordinate them with your BMX seat clamp or your BMX bar pads for a consistent look.

What a cap does not do

A cap does not hold pressure: sealing is the job of the valve core. If your tyre goes down slowly, check the core, the valve nut and the rim tape before blaming the cap. A core remover and a gauge pump, both in our BMX tools section, settle the question in two minutes.

Brands available

• Tangent: anodised alloy caps, wide choice of colours
• Box Components: clean machining, effective knurling
• Insight: simple, affordable references
• Stay Strong: colours matched to its own accessories
• Pride: understated finishes, in Presta and Schrader

The BMX RACING advice

Not sure which valve your tubes use? Look at the stem: slim and threaded to the top means Presta; wide and cylindrical means Schrader. If in doubt, send us a photo and we will confirm the right cap and, where needed, the matching inflation adaptor. Dispatched within 24 to 72 hours and you can spread the cost over 2 or 3 payments available.