BMX Pro

BMX Pro: stepping into the adult classes

The Pro size marks the move into the adult classes, raced from 16 years old by men and women alike. The rider leaves the youth formats behind for a full-size frame drawn around a 161 to 172 cm build. It is not only a question of length: the wheel format changes with it.

Placing yourself on the sizing chart

Around 172 cm everything comes down to inside leg and to riding style. A 171 cm rider with long legs, often up on the pedals, breathes more easily on a BMX Pro XL; at 173 cm with a long torso and shorter legs, you keep more control in Pro. A reliable marker: in the gate position, elbows bent, the back stays at roughly 45 degrees without the arms locking out. Coming up from Expert XL, allow a few sessions to settle in.

What the track asks of an adult rider

Adult motos are run off high start hills, down straights where speed never drops. The gate start happens standing, weight driving through the cranks, and rhythm sections are pumped rather than jumped. A correctly sized frame lets the hips travel back behind the bottom bracket axis on landing, and that margin is exactly what a short bike takes away.

What defines a Pro frame

• Top tube quoted between 20.5" and 20.75" depending on the maker
• 406 rims in 20 inch, run in 20x1.50, 20x1.60 or 20x1.75
• Three-piece crankset with cranks of 170 to 175 mm
• Shell in the Euro, Mid or Spanish standard, frame depending
• Rear end in 10 mm or 20 mm, hub drilled 28 or 36 holes
• V-brake callipers, or disc where the tab is provided

451 to 406: what the tyre changes

In Expert XL, the 451 rim runs 20 x 1-3/8", narrow and fast. The 406 takes far more volume: the tyre soaks up landings, grips harder in a berm and forgives an untidy line, at the cost of a few hundred grams. No wheel part crosses between the two formats, whereas the drivetrain, stem, handlebars and saddle almost always carry over.

Gearing: the ratios that come up in Pro

Most adult riders sit around 44x16, drop to 43x16 on short tracks where drive out of the corners matters, and go up to 46x16 when the start straight is long and the hill is high. Fine-tuning happens at the chainring rather than the sprocket, to keep sensible chain tension at the tensioner. A 1/8" chain for durability, 3/32" to save weight.

The brands in Pro size

Inspyre designs its frames in France and covers the Pro size across several levels. Chase builds on triple-butted 6061-T6 aluminium tubing. Meybo, the Dutch benchmark, runs from club model to full race build. Supercross works on geometries cut for the gate start, while Pride and Stay Strong sit at the top end. At equal size, head angle, bottom bracket height and real weight differ from one model to the next.

The BMX RACING advice

Tell us your height, your inside leg and how often you train: we settle the call between Pro and the size above, then confirm crank length and brake type before shipping. The whole chart sits together in the BMX bikes and frames section. Dispatched within 24 to 72 hours, you can spread the cost over 2 or 3 payments.

Still weighing Pro against Pro XL? Our size-by-size comparison of BMX race frames lists top tube, inside leg and cranks for each.