Junior gearing can be a surprise to young athletes trying the sport of cycling for the first time. The young athlete attending his first USA Cycling-sanctioned event may be shocked to find his bicycle considered illegal. Parents may also wonder why this is so, especially when they have paid a lot of money for a bicycle they were told was race-ready. The main purpose of junior gear restrictions is to help the young rider develop a good pedal cadence and to avoid injury. Junior gear restrictions also level the playing field for developing juniors who may be at a disadvantage against rivals who possess physical advantages such as height and power.
The test to see if a race bike is legal or not is called the “rollout method” or simply “junior rollout,” which is the distance a bike travels backward in a straight line through one full pedal revolution when the bicycle is in its largest gear. The junior gear restriction for road events is 26 feet (7.93 meters).
To calculate how far a bike will travel relative to its gears, USAC suggests gear ratios with respect to race age and discipline. The gear limit for a rider is determined by the age of the rider and the discipline, and applies in all events in that discipline. There is no restriction for cyclo-cross or mountain bike races. For road and track the limits are*:
6-18: 7.93 meters (26’)(52×14)
15-16: 6.93 meters (22’9″)(50×15)**
13-14: 6.45 meters (21’2″)(50×16)
10-12: 6.05 meters (19’8”)(48×17)
*Note that the gear ratios listed are merely suggestions – the distance rolled out is the governing standard.
**For 15 & 16-year-old juniors who are competing in keirin or Madison championship events, the 17-18 (unrestricted) gear limit applies.
Race officials will usually provide a courtesy gear check prior to the start of a junior race but ultimately it is the gear check immediately after the junior race that determines whether a junior’s bicycle is legal or not.
The official checks a junior’s bicycle’s gears not by counting the number of teeth on the largest chain ring and smallest cassette cog, but by rolling the bicycle backward in a straight line for 26 feet. If the bicycle travels 26 feet or less when rolled backward one full pedal revolution, the bicycle is legal. If the bicycle rolls past 26 feet, the rider is disqualified for not complying with the junior gear restriction.
Ultimately it is the athlete’s responsibility to make sure his bicycle is compliant with junior gear restrictions. The purpose of the courtesy check is to offer the junior the opportunity to block their gears prior to competing in his event. Note that blocked gearing is not permitted at USAC National Championship and UCI events.
Depending upon the rear derailleur’s stop limits and rear cassette cog combination, there is no guarantee that a bicycle with blocked gearing can be made legal, since it all comes down to the distance traveled in the largest accessible gear. Blocking means adjusting the rear derailleur’s high stop limit screw to prevent the chain from going to a small rear cassette cog.
It is also important to note that not all cycling tires have the same diameter, which can give a bicycle a rollout distance different than the distance provided by the gear recommendation.
Junior riders need to roll out their bicycles on their own prior to attending a USAC-sanctioned event to determine whether they will be compliant with the rules.