Dirt Jump Frames

Chromoly vs aluminium for DJ

Most serious DJ riders prefer chromoly steel. It flexes slightly on impact (more forgiving on landings), is easy to repair if it gets damaged, and takes peg grind abuse for street riding. Brands like NS Bikes, Dartmoor, and DMR primarily use chromoly. Aluminium DJ frames are lighter and stiffer — better for pure dirt jumping where you want snappy response. Both materials are built to take serious abuse.

Geometry matters

DJ frames have uniquely compact geometry — short chainstays (365–380mm), low bottom brackets, and short wheelbases for quick manoeuvring in the air. Head angles are typically 67–69° with a short reach. This isn't like trail bike geometry — it's designed for pumping, popping, and controlling the bike in the air. A longer, slacker frame will feel sluggish on jumps; too short and twitchy will be unstable on bigger hits.

What to check on a used DJ frame

DJ frames get hammered. Check the head tube and down tube junction — this takes massive force on every landing. Look at the dropouts for cracks or spreading. On steel frames, check for rust at the bottom bracket shell and inside the seat tube (remove the post and look). Peg mounts (if present) should be intact. Dents on steel are usually cosmetic; dents on aluminium weaken the frame. If the frame has been used for street, expect cosmetic damage — what matters is structural integrity at the welds.

Building up a DJ bike

DJ builds are simple and cheap. You need a frame, a short-travel fork (80–100mm), one rear brake, a wheelset, cranks, and a chain — no derailleur, no front brake, no dropper post. Most parts are interchangeable and widely available used. A complete DJ build from used parts can easily come in under £500. The simplicity is part of the appeal.

Popular DJ frames on Cranxs

Common listings include NS Metropolis, NS Movement, Dartmoor Two6Player, Dartmoor Cody, Santa Cruz Jackal, DMR Sect, Commencal Absolut, Canyon Stitched, Octane One Void, and Transition PBJ frames. Need a complete bike? Browse dirt jump bikes.