Junior racers (race age 9 – 18) have specific rules for restrictions to gearing on race bicycles. The reason for these restrictions is to promote “spinning” instead of pushing too tall / hard a gear. Spinning tends promote fairness within the age groupings of juniors, since all juniors mature at different rates. It’s thought that racers of all ages can spin the cranks fast, but only the more physically mature riders can push those taller “adult” gears. There are theories that pushing too tall a gear on young / developing joints can also lead to stress injuries. As such, these gearing restrictions have been in place for many years. It’s worthwhile to note that European junior racers are under even more restrictive gearing requirements. Those aged 16 and under have more restrictions (easier gears) than in the USA. This is important to know if you ever race in Europe!
In the USA, all juniors of race age 9 – 18 have the same restriction for road races. The official rules are posted at the bottom, but here’s a much more detailed explanation:
At all races, junior gearing will be inspected by race officials. This may happen before the race, or immediately afterwards. The inspection is typically done by a “gear rollout” process. There are two stripe / tape marks posted on the ground in a designated area. The racers will present their bikes facing backwards at the first stripe, with the pedal in its most downward position and with the bike in its tallest gear (chain on the smallest cog on the rear cassette and on the largest chainring up front). The rider will straddle the front wheel and lift up on the bars to support the front wheel off the ground, then walk the bike in a straight line until the second stripe is reached. An official will inspect the bike at the first stripe and at the second stripe. They will be looking to see how far the crank turned between both stripes.
The stripes are exactly 26 feet apart. The rule states that the crank must turn at least one complete rotation when the bike is rolled along that 26 foot distance. If it turns less than one rotation, it means that the gearing is too tall and is considered “illegal” (offering an unfair advantage). If this occurs before the race, you may be given the opportunity to correct this by “blocking gears” (more about this later). If it’s after the race, it means you will most likely be relegated or possibly disqualified for using illegal gearing. You don’t want that to happen!!
Most bikes come with “adult” gearing. It’s up to the junior to modify the gearing to meet these rules. Here’s how that’s typically done:
- You can install a different (smaller) chainring or a cassette with a larger tooth count.
- You can “block gears” (turn a limit screw on the rear derailleur) to prevent the rear derailler from accessing the smaller cogs. NOTE: this process can often achieve “legal” gearing, but will reduce the number of gears you can shift into. It’s good for most local races, but will not qualify for racing at National Championships.
There are a lot of bike choices out there, but here are the most common gear options to meet the restrictions:
Use a 52 tooth chainring with a junior-specific cassette that has a small cog with 14 teeth. You can get a 52 ring for almost any bike (standard or compact / mid-compact cranks). Shimano sells a 10 speed and an 11 speed version of the needed cassette. There are a (very) few other manufacturers that offer such cassettes. SRAM does NOT currently offer any junior cassette options. Here are the Shimano cassettes:
Shimano Ultegra 10 speed cassette: CS-6700 (14/25) UPC# 4524667077183
Shimano Ultegra 11 speed cassette: CS-R8000 (14/28) UPC # 689228623422
It may also be possible to meet the restriction with a special 45 tooth chainring (available from a company called Dimension) and combine that with a cassette that has a 12 tooth small cog (a little easier to find than the junior specific cassettes). They make one for 110 BCD (compact cranks) # CR1936 (black) or # CR1937 (silver). The one for 130 BCD (standard cranks) is no longer made. https://dimensionbikeproducts.com/products/chainrings/chainrings
Another company called Wickwerks makes a product they call the “Junior Solution”. It’s a 41 tooth chainring and a front derailleur adapter that allows the front derailleur to shift properly to those smaller rings. https://wickwerks.com/products/juniors-solution-combo-kit/ This should work with a regular cassette with an 11 tooth small cog.
The above assumes you are using tires that are maximum 26 mm wide. Wider tires (28 mm are becoming more common) also have a larger diameter. That means they travel farther with each rotation. Enough that it can make a bike fail the gear rollout! Try to stay with 26 mm or narrower tires.
The above is for the majority of bikes juniors presently use. But there are some bikes with smaller wheels (650c, 26 inch or 24 inch) that younger juniors sometimes use. These may or may not meet restrictions!
And now there are new 12 speed components, bikes with single chainrings (“1x”) and cassettes with 10 tooth small cogs. All of these can cause confusion and problems on race day! If there’s any question on your bike, you can always check it yourself. Measure a 26 foot distance on your driveway, then do your own gear “rollout” test! If you fail, you might try smaller chainrings, blocking gears, or a combination of those.
To take some of the confusion out, try a free app for your phone! There are several out there for iPhone and Android. One called “Gear Calculator” allows you to plug in your cassette size, chainring size and tire size. Then you can select “gear rollout” and it will tell you how many inches of travel the bike will go in the tallest gear with one crank rotation. 312 inches (26 feet) is the legal limit you need to stay under.
There’s such a thing as being “too legal” as well! While it’s legal to race with excessively restricted gears, it may put you at a disadvantage. For example, many bikes come with a 50 tooth chainring. If you put a junior cassette (14 tooth cog) on that, your bike will travel 18 inches less with one crank rotation than another rider with a 52 tooth chainring. That’s pretty significant and you’ll have to spin much faster to go the same speed!
Here are the official rules per the USA Cycling Rulebook:
1I4. Youth/Junior Gears. The maximum chaingear ratio for Junior riders is based on age and discipline. Blocked gears will be allowed, except in National Championships or selection events for international competition. All tests for compliance shall be done using the “roll-out method*” There are no gear restrictions for Cyclocross or MTB races.
(a) For road and track the limits are:
Road
6-18: 7.93 meters (26’)(52×14)*
Track
17-18: Unrestricted
15-16: 6.93 meters (22’ 9”)
13-14: 6.45 meters (21’ 2”)
9-12: 6.05 meters (19’ 10 1/4”)
(b) 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 subject to the notes shown below:
(i) In Track events, Junior riders competing in a race for an older age group may use the same gear limit, if any, applied to that race. Note that the gear combinations listed are merely suggestions.
*Roll-out is the distance covered with one full revolution of the pedals in the USA Cycling Rule Book | 29
largest gear available on the bicycle. Note that the gear combinations listed are merely suggestions.
