To protect youth riders from overuse injuries and ensure all racing is held on an equal basis, gear restrictions are in use in all British Cycling events.
It is good practice to for riders to ride with these gear restrictions throughout the year so that the appropriate leg speed and cadence is developed.
The gear restrictions are measured by the distance the bike will travel through one complete crank turn with the gears in the highest position.
British Cycling gear restrictions information.
This can be quite complicated so below are some gearing suggestions to try based on full size wheels;
U8 – 5.1m : 34 x 15
U10 – 5.4m : 34 x 14
U12 – 6.05m : 34 x 13
U14 – 6.45m : 39 x 13 or 42 x 14
U16 – 6.93m : 39 x 12 or 42 x 13