***UPDATES***

The NEW 12-speed Youth cassttes are now in-stock - CLICK HERE

Our new NEW HUP straatrace road racing (disc brake) frames have just arrived! CLICK HERE

The following advice is aimed at Road & Triathlon gear restricted racing (for MTB gearing, see bottom of the page).

British Cycling & Triathlon Youth Gear Restrictions – a guide to Rollback Limits & Locking Off Gears…the road season is back on, so if you are new to British Cycling road racing or moving up an age category, take a look at our reference guide. (British Triathlon are also continuing to roll-out gear restrictions to more and more events, it looks like this will become common place on kids triathlons in the near-future!)

Update - Disc brakes are now eligible to race in British Cycling events!

Unlike other forms of Cycle Racing which have no restrictions, Road Racing to British Cycling Regulations has limits based on Age Group category. These are important to protect the children from overloading their muscles during a race (pushing too large a gear) and to maintain a level playing field between competitors.

Each age group has a gear restriction in the form of a ‘Rollback’ distance (see table above). This is the distance covered for 1 full revolution of the crank, in the bikes highest (fastest) gear. It might sound complicated, but isn't in reality.

British Cycling & Triathlon Youth Gear Restrictions

Common Component Combinations for BC Categories

There is a huge number of possible component variations to match gear limits, but here is a short list of the common, easily achieved set-ups using our stocked cranks, chainrings, cassettes, wheels and tyres:

20″ wheels;
406mm wheels (28c tyres) use 38T chainring and 11t sprocket for U8’s/TriStart*
451mm wheels (28c tyres) use 38T chainring and 12t sprocket for U8’s/TriStart*
451mm wheels (21c tyres) use 38T chainring and 11t sprocket for U10’s/TriStar1*

24″ wheels;
507mm wheels (28c tyres) use 36T chainring and 13t sprocket for U8’s/TriStart*
507mm wheels (47c tyres) use 32T chainring and 12t sprocket for U8’s/TriStart*
507mm wheels (47c tyres) use 34T chainring and 12t sprocket for U10’s/TriStart*
520mm wheels (25c tyres) use 34T chainring and 12t sprocket for U8’s/TriStart*
520mm wheels (25c tyres) use 36T chainring and 12t sprocket for U10’s/TriStar1*
540mm wheels (25c tyres) use 40T chainring and 14t sprocket for U10’s/TriStar1*

26″ wheels;
559mm wheels (28c tyres) use 36T chainring and 13t sprocket for U10’s/TriStar1*

650b wheels;
584mm wheels (650b x 25c tyres) use 30T chainring and 12t sprocket for U8’s/TriStart
584mm wheels (650b x 25c tyres) use 32T chainring and 12t sprocket for U10’s/TriStar1
584mm wheels (650b x 25c tyres) use 36T chainring and 12t sprocket for U12’s/TriStar2

700c wheels;
622mm wheels (25c tyres) use 36T chainring and 15t sprocket for U8’s/TriStart*
622mm wheels (25c tyres) use 38T chainring and 15t sprocket for U10’s/TriStar1*
622mm wheels (25c tyres) use 34T chainring and 12t sprocket for U12’s/TriStar2*
622mm wheels (25c/27c tyres) use 36T chainring and 12t sprocket for U14’s/TriStar3*
(Above recommendations on 1x cranks (riders shorter than 155cm), below on 2x cranksets (riders 155cm+)
622mm wheels (25c/27c tyres) use 48T chainring and 16t sprocket for U14’s/TriStar3*
622mm wheels (25c tyres) use 52T chainring and 16t sprocket for U16’s/Youth*
622mm wheels (25c tyres) use 52T chainring and 14t sprocket for U18’s/Junior*

Alternative and popular U10 set-up...
For those using a bike for CX and Road/Tri gear limited events is: 30T chainring and 12t sprocket on 27c tyres on the HUP evo frameset - using the standard 10-speed 11-34t Microshift cassette. Perfect gearing for CX at this age and accurate Road gearing for the U10 category, using 27c tyres compatible on the HUP evo frameset.

Additional Popular Track Gearing on 700c;
622mm wheels (25c tyres) use 38T chainring and 16t sprocket for U8’s*
622mm wheels (25c tyres) use 38T chainring and 15t sprocket for U10’s*
622mm wheels (23c tyres) use 40T chainring and 14t sprocket for U12’s*
622mm wheels (25c tyres) use 42T chainring and 14t sprocket for U14’s*
(Above on HUP 4-bolt cranks (riders shorter than 155cm), below on Miche 165mm cranks (riders 155cm+)
622mm wheels (23c tyres) use 49T chainring and 16t sprocket for U14’s*
622mm wheels (23c tyres) use 49T chainring and 15t sprocket for U16’s*

*Component manufacturing tolerances can affect your actual rollout, especially tyres. Always physically check before heading off to a race!

As you can see above, kids up to and including U12 usually run 1x single chainring setups, in U14 and above they usually run double chainring setups - however, correct length crank arms for double chainring setups are few and far between. Taking a typical 12yr old at 152cm tall for example, they would ideally run a 155mm long crank (10% rule) but standard adults cranks usually start at 165mm at their shortest.

**Fashions for wider tyres mean wheel widths are increasing, something that isn't too helpful for the kids! Be careful in the U8 and U10 categories, as your choice of wheelset will dictate your choice of tyres and gearing options. You cannot fit a 20c tyre to a 16c inner width rim. Similar issues are arising with modern trends in frame design towards wider, press fit Bottom Brackets and their lack of compatibility with square-taper short cranksets!

 There are solutions to these problems however:  CRANKSETS, CHAINRINGSCASSETTES & WHEELS/TYRES

Cassette selection is another key decision, so a couple of points to understand. Mechanical rear mechs can usually only 'lock-off' 2 sprockets as a maximum (so a 12-28t can have it's 12t & 13t locked-off, to use the 14t for U10 gearing on 20c tyres for example). Electronic rear mechs cannot 'lock-off' gears, so need the correct smallest sprocket on their cassette for the rollout. If they use the bike in non-race situations, being able to 'unlock' their gears can give them added flexibility. Conversely, using the correct cassette (without the need to 'lock-off') will allow them to use all their gears.

Our unique range of Miche Primato 10-speed and 11-speed cassettes for youth/junior racing fit every requirement!

This is how to check your bike…

  1. Place your bike in its highest gear (largest front Chainring, smallest rear Sprocket) with tyres at race pressure
  2. Lay a tape measure on the ground, position the bike with a crank arm vertically down, inline with the beginning of your tape measure)
  3. Roll the bike backwards (keeping it in a straight line) until the crank goes through 360 degrees (1 full rotation) and stop when it is vertically down again.
  4. As long as the distance covered is less than your age groups maximum ‘Rollback’ distance, the bike is legal. If its longer, repeat using the next Sprocket up.
  5. If you need to use a gear lower than its highest gear, you need to ‘lock off’ that gear so it can’t be used during the race – a simple task outlined below.

To lock any gears off and make your bike legal, simply follow these steps. Put the bike in its correct front Chainring and correct rear Sprocket to comply with the relevant Rollback…

  1. Using a screwdriver, turn the derailleur limit screw marked ‘H’ (for High), until you cannot change the gear any further down the Sprocket than is needed.
  2. Turning the screw marked ‘H’ clockwise (until it is not possible to select the smaller Sprocket) limits the overall travel of the rear mech in the high gears. Conversely, the screw marked ‘L’ (Low) can limit the overall travel in the lowest (largest) Sprockets, but you should not need to limit the lower gears.

The same procedure can be used to lock-off the larger front chainring too.

British Cycling Events...

During all British Cycling events all riders bikes are checked by the Scrutineers prior to the race (after signing-on) to ensure they are within the age group’s Rollback limit. Never attempt to cheat this, Podium finishers (and others selected at random) are re-tested immediately after the race is finished.

Why are very few bikes sold, at or near the gear limits? There are several reasons why bikes are rarely manufactured to match the BC Gear Restrictions;

  1. Due to size differences of children, many bikes are suitable for kids in several different age group categories.
  2. Not all bikes are targeted solely at Road racing, but are also suitable for Cycle-cross, which is un-restricted and benefits from different gearing.
  3. Economies of scale in manufacturing means it can prove expensive to specifically target one BC age group gearing, making the bike less appealing.

Because of this, its not uncommon to upgrade/modify gearing to get closer to the age groups limit, especially in the more competitive U12/14/16 and Juniors.

Finally, bear in mind the individual components that affect Rollback. Alongside front Chainring size (No of teeth) and the rear cassette Sprocket sizes (No of teeth) the overall diameter of the tyre and pressure are also critical. Not all 23c tyres are the same profile, so this can affect Rollback! Because of this, whilst you can manually calculate your Rollback mathematically (Front Teeth/Rear Teeth x Tyre Dia x π) there is no substitute for physically checking it before you race. See the tables above for age group gearing limits. Adititionally;

  • a rim made of aluminium or carbon fibre
  • a maximum rim depth of 35mm
  • a minimum of 16 spokes which can be round, flattened or oval
  • spokes which do not exceed 3mm in width

Don't forget, youth cyclo-cross events do not have wheel depth restrictions of 35mm, only the Road and Track events.

British Triathlon Events...

Gear Restrictions for Elite Tristar and Youth Draft-Legal Events

After a successful trial in 2015, British Triathlon amended the 2016 Rulebook for certain Elite level, draft-legal Youth Triathlons – imposing gear restrictions for the different age groups (matching the British Cycling Rollback limits, for the corresponding age groups). For 2017, the scope has increased again to cover all tarmac events for TriStar 2 and upwards age groups on SWS events.

2019 Update - Disc brakes are now eligible to race in British Triathlon events!

For 2018 it was been further extended to include all Tristar age categories on Draft Legal (tarmac) events. In addition to applying gear restrictions (which match British Cycling's limits in the table above) they have also introduced wheel restrictions, just to make the issue more complicated! 

TriStars

Will ride on standard or traditional wheels ONLY. A traditional wheel for this age group is defined as:

  • a rim made of aluminium (carbon rims are not permitted)
  • a maximum rim depth of 35mm
  • a minimum of 16 spokes which can be round, flattened or oval
  • spokes which do not exceed 3mm in width

Youths

Will ride on

EITHER

A standard or traditional wheel defined as:

  • a rim made of aluminium (carbon rims are not permitted)
  • a maximum rim depth of 35mm
  • a minimum of 16 spokes which can be round, flattened or oval
  • spokes which do not exceed 3mm in width

OR

Wheels that are found on the UCI non-standard approved wheel lists (includes HUP CD35, TD35, CD50 & TD50 UCI approved wheels)

Its only a matter of time before all events are gear-restricted. We think this is good news, as the same benefits will apply to young Triathletes, as they do to young Cyclists. We also hope they expand this to all age groups in the near future.

MTB Gearing Advice

Depending on the type of riding you will be doing, there are several options for MTB gearing...

XC: smaller/lighter gearing is common using 11-34t or 11-36t cassettes, but noting wrong with using a larger cassette, but they do get heavier. Chainring size is always dependant on rider strength - typically a younger rider is better off using a small 30T chainring, older and stronger a 32T or 34T chainring.

Enduro: larger gearing is more common, for those longer, sustained climbs: 11-42t, 11-46t & 11-48t are most popular. Chainring size is always dependant on rider strength - typically a younger rider is better off using a small 30T chainring, older and stronger a 32T or 34T chainring.

Take a look at the different models: Cyclo-cross | Road | Triathlon | MTB | Gravel | Track