Components
Browse used BMX components for sale from riders across the UK. This covers everything that bolts to the frame and forks: 22.2mm bars in 8.5in to 10in rises, top-load and front-load stems, integrated 1-1/8in headsets, mid and Spanish bottom brackets, three-piece cranks on 19mm to 24mm spindles, 25t and 28t chainrings, U-brakes, pedals and bar ends. Most listings are single parts left over from a build, which is how a stock complete gets upgraded a piece at a time.
Which BMX components will fit my bike?
Freestyle BMX is unusually standardised: bars clamp at 22.2mm, steerers are 1-1/8in, three-piece cranks take 9/16in pedals, and drivers run a 1/8in or half-link chain. The parts that do not swap freely are bottom brackets and cranks, where a mid shell at 41.3mm takes different cups from Spanish at 37mm or American at 51mm, and bearings must match the 19mm, 22mm or 24mm spindle they sit on. Check the shell size stamped on or measured across your frame before buying a crankset.
How do I choose bars and stems?
Rise sets your position more than anything else: bars run from about 8.5in for shorter riders and tight park setups to 10in for street, usually with 11 to 12 degrees of backsweep and 1 to 3 degrees of upsweep. Stems come front-load, which is easier to fit and stiffer, or top-load, which drops the bars a few millimetres, with reach between 48mm and 53mm changing how far forward you sit. Bars can be trimmed a few millimetres each side but never lengthened, so buy on the wide side.
Will mountain bike parts fit a BMX?
Very little crosses over. MTB bars clamp at 31.8mm or 35mm and are far too wide, MTB cranks are built around external bottom brackets that no BMX shell accepts, and modern MTB forks use tapered steerers where BMX runs a straight 1-1/8in with a 45x45 integrated headset. Pedals with a 9/16in thread do swap, and so do some seat clamps, so treat any part described as coming off a mountain bike as a sizing question before anything else.
What wears out on used BMX components?
Bars are the part to be careful with: inspect the knurled clamp area for deep gouges and look for hairline cracks at the crossbar welds, and pass on any set that has taken a hard front-wheel case. Stem bolts round off and strip their threads, headset cups develop an indexed notch you feel as a click when the fork self-centres, crank spindles wear at the splines and start creaking under load, and chainring teeth hook into a shark-fin profile once a chain has stretched. On pedals, spin the spindle for play, check plastic bodies for missing pins, and expect brake pads and cables to be replaced outright.
How much should used BMX parts cost, and when is new better?
Cranks, bars and stems from established names hold roughly half their new price when straight and unmarked, and they are the sensible things to buy used because there is little inside them to fail unseen. Bearings, cables, brake pads and bar ends are cheap enough new that second hand saves nothing, and a headset or bottom bracket with rough bearings should be priced as though the bearings are missing. If you are replacing four or five parts at once, price up a second-hand complete bike first, because a whole bike often costs less than the sum of its parts.