| Rider fit | With the child seated and wearing usual riding shoes, check whether the seat can be adjusted for their inseam. | The child can place both feet flat on the ground while seated, with knees slightly bent. A low enough seat supports walking and stopping. | Inseam and available seat-height range (cm); feet flat: yes/no. |
| Handlebar reach | Ask the child to hold the grips while seated in a relaxed, upright position. | The child can hold both grips without stretching uncomfortably; the handlebar turns freely without contacting the frame or the child’s legs. | Comfortable reach: yes/no; steering interference: yes/no. |
| Wheel and steering check | Before riding, check that both wheels are secure and spin freely, and that the handlebar moves smoothly from side to side. | No visible looseness, binding, or wheel wobble. Inflate pneumatic tires only within the pressure range printed on the tire sidewall. | Wheel play or wobble: none/observed; tire pressure checked: yes/no. |
| Straight-line tracking | Have an adult guide the bike at walking speed over a straight, level stretch of about 3 m, then let the child try at a comfortable pace. | The bike rolls smoothly without a persistent pull to one side, and the child can steer with small, controlled movements. | Distance (m); persistent pull: yes/no; control: easy/uncertain. |
| Walking-to-gliding balance | On a clear, level surface, let the child walk the bike forward and try a short glide when ready. Observe up to 3 attempts; do not push the child to lift their feet. | The child can put both feet down readily and can begin and end a glide without the bike tipping unexpectedly. | Attempts observed (1–3); controlled starts and stops: yes/no. |
| Turning control | At walking speed, ask the child to make a broad turn in each direction in an open area. | Steering feels smooth, the child can keep the bike upright at low speed, and the handlebar does not hit their legs. | Left turn: controlled/uncertain; right turn: controlled/uncertain. |
| Stopping and brake check | First check that the child can stop by putting their feet down. If a hand brake is fitted, test it at walking speed in a clear area. | The child can reach and operate the brake, if present, and it slows the wheel smoothly. Stopping distance varies with speed, surface, tire condition, and rider. | Feet-down stop: controlled/uncertain; brake fitted and reachable: yes/no/not applicable. |
| Post-test inspection | After the trial, recheck the wheels, handlebar, seat adjustment, tires, and any fitted brake for movement or damage. | No parts have loosened or become damaged. Stop using the bike and address any defect before riding again. | Loose parts or damage: none/observed; follow-up required: yes/no. |