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Youth & Junior Race Bikes - Demystifying Gearing Restrictions


Enthusiastic Youths & Juniors can sometimes arrive at their first race, nervous, excited, eager to compete - only to be told that their bike falls foul of the regulations, 'because their bikes gearing is not compliant with the rules.' This can be confusing and frustrating for rider and parents, especially if a brand new bike was purchased in good faith and the shop said that the bike was 'race-ready.'

Far from being over-zealous kill-joys, race oficials must follow the regulations set by international and national cycling organisations, which limit the top gear for all youth and junior racers participating in road and track races. This is because gear restrictions teach good pedaling techniques that will be essential later in life, help prevent injury, encourage good race tactics and level the playing field when children are developing at different rates.


Above - All i-Youths and Juniors use gears appropriate for their age category IN TRAINING as well as when racing.


  • Young riders develop at different rates, restricting gears helps put all riders on a fair and equal standing, rather than always favouring the strongest children who happen to develop early. (Such early developers might win lot's to start with but then struggle later when it comes to Junior and Adult racing.)
  • Young bodies repair quickly but are vulnerable to overuse injuries, restricting gears helps to avoid injuriies due strength imbalances in fast growing children.
  • To be succesful as an adult in bike racing, you have to pedal big gears fast - not push big gears slowly. So you first have to teach your body to pedal restricted gears fast, ready for when the real strength comes later in life.
  • Restricted gears encourage young riders to succeed in races using tactics, as opposed to races being dominated to who can push the biggest gear in the group. This will help to support the riders in learning the techniques which they will need throughout their competitive career.


All bikes should be checked prior to the event and the first three riders plus any picked at random in addition to those using gear locking should be rechecked as soon as the event finishes. If a bike does not meet the regulations the rider will be disqualified.
Please note that the sprocket and chain ring combination cannot be used in isolation to assess gear size. The absolute measure for gear restriction is the distance travelled in one complete revolution of the cranks.

Tyre dimensions; please be aware that although the manufacturer may detail their tyres as a standard dimensions, there will be variations from brand to brand. For example because it says “23” on the side does not mean it’s the same as another tyre with “23” on the side,


The test to see if a race bike is legal, i.e. if it's top gear is not over the biggest (hardest to push) gear that is permitable for each age category, is called the "rollout test" - it checks the distance that a bike travels in a straight line with one full pedal revolution, when in top gear.


Click Here for video on how to perform a gear check



  • YOUTH A (Under 16 - from 1st January in year of 15th Birthday until 31st December in year of 16th birthday) Maximum Gear = 6.93 metres (e.g. 39x12 / 42x13 / 47x15 / 52x16)
  • YOUTH B (Under 14 - from 1st January in year of 13th Birthday until 31st December in year of 14th birthday) Maximum Gear = 6.45 metres (e.g. 39x13 / 42x14 / 45x15 / 51x17)
  • YOUTH C (Under 12 - from 1st January in year of 11th Birthday until 31st December in year of 12th birthday) Maximum Gear = 6.05 metres (e.g. 39x14 / 42x15 / 45x16 / 48x17)
  • YOUTH D (Under 10 - from 1st January in year of 9th Birthday until 31st December in year of 10th birthday) Maximum Gear = 5.40 metres (e.g. 41x16 / 43x17 / 46x18 / 49x19)
  • YOUTH E (Under 8 - until 31st December in year of 8th birthday) Maximum Gear = 5.10 metres (e.g. 39x16 / 41x17 / 43x18 / 48x19)

N.B. For track and roller racing events where an exceptionally talented Youth A, B or C rider has received dispensation from British Cycling HQ to compete against riders of an older category, then that rider shall be restricted in gearing to that of the older category.

  • JUNIORS (Under 19 / OVER 16 - From 1st Jan of year in which 17th birthday falls to 31st December of year in which 18th birthday falls.)  Maximum Gear = 7.93 metres (e.g. 52x14)

Click Here to Download a chart of gear ratios


"I've done a roll-out test on my son's road bike but the gear is too big - what can I do?"

If your gear is not too far over, the easiest thing to do is to adjust the rear deraileur, using the limit screws, so that the chain will not go onto the smallest sprockets and/or adjust the front deraileur so that the chain will not go on to the large chainring. If this is beyond the adjustment limits of the deraileur, you will have to buy a new cassette for the rear and possibly new chain rings.


You can buy after market chainrings in lots of different sizes to fit any cranks - but you need to know the PCD (pitch circle diameter) - it should be etched on your existing chain rings next to where it says number of teeth.

  • Modern Campagnolo are typically 135mm PCD
  • Shimano are 110mm PCD
  • Some FSA cranks are different again and are 130mm PCD.

It may be easier / cheaper to buy new cranks to suit the rings that are available - in which case, you should go for 165mm cranks. 170mm are just about OK but 172.5 are more difficult to spin with restricted gearing and long cranks over 165/170mm in length are far from ideal as they place a lot of strain on knee joints.

BBB do a range of SRAM and Shimano compatable Youth and Junior casettes with a 16 tooth smallest sprocket

"Guy, what would you recomend is the best combination for a me? I am a Youth B (U14) I'm currently allowed a maximum gear of 6.45m, e.g. 46 tooth biggest front chainring and a 15 tooth smallest rear sprocket. The trouble is that my bike came with 53 and 39 tooth chainrings and a 13/14/15/16/18/20/23/26 rear cassette - but if I wind the rear deraileur screw all the way in, I can't stop the chain from going on to the small sprockets..."

The no-cost option is to adjust the front deraileur so that you can't use the big chainring (but can still trim the front mech to avoid chain rub) The problem with this set up is that gears are really not designed to run that far out of line (bigest sprocket and biggest chain ring or smallest sprocket and smallest chainring) - this combination will run rough, wear out your chain quickly and may jump in a sprint.

I would recommend buying a 45 tooth chainring - put your 53 ring aside for a few years. This will then give you 45 & 39 tooth chainrings up front - pretty close ratio but stll usable and it will help with keeping the chain from unshipping. Depending on how narrow your tyres are, you might get away with a 46 tooth chainring up front, which would be ueseful for Youth A gears in a season or 2.

"Can I buy a Youth bike with everything set up correctly for Youth racing?"

Definitely, I recommend the following:

Road Bikes: Isla Bikes offer a great range

Track Bikes: Dolan make some of the best

Youths grow out of their bikes quickly, so you should be able to find one of the above 2nd hand on eBay etc. and purchase it for less than the cost of a new so-called youth bike that has gears that are not appropriate for racing.

Alternatively, if you are mechanically minded, you can start form scratch with a small frame and build up with 2nd Hand parts such as in these 2 examples:


Above, keeping it all in proportion: Youth C custom bike, built from scratch around a 43cm women's frame, with:

  • Full size 700c wheels
  • 155mm cranks
  • 45 x 34 chainrings
  • 16 up rear casette


Above, money-no-object for a very lucky Youth E - imported from Italy!

  • 550c wheels (tubulars)
  • 145mm cranks
  • 42 x 34 chainrings
  • 15 up rear casette

Edited by Guy_Watson

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