GBP

British Cycling & Triathlon Youth Gear Restrictions

***UPDATED January 2025 for implementation from 01/03/25***

Our gearing advice for Road, Triathlon! You can also find advice on CX, MTB & Gravel at the bottom of the page.

The following advice is aimed at British Cycling & Triathlon Youth Gear Restricted events – a guide to Rollback Limits & Locking Off Gears. So if you are new to British Cycling or British Triathlon racing or moving up an age category, take a look at our reference guide. Unlike other forms of bike 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.

The bike components that affect the rollout (so need to be carefully selected for Road and Triathlon) are: wheels, tyres (including their pressure), cassette and chainring. So this is how to check your bike before going to a race…

  • Place your bike in its highest gear (largest front Chainring, smallest rear Sprocket) with tyres at race pressure
  • Lay a tape measure on the ground, position the bike with a crank arm vertically down, inline with the beginning of your tape measure)
  • Roll the bike backwards (keeping it straight) until the crank goes through 360 degrees (1 full rotation) and stop when it is vertically down again.
  • If 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.
  • 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 gears off and make your bike legal, follow these steps. Put the bike in its correct front Chainring and correct (smallest) rear Sprocket to test the Rollback…

  • Using a screwdriver, turn the derailleur limit screw marked ‘H’ (High), until you cannot change the gear any further down the Sprocket than is needed.
  • Turning the screw marked ‘H’ clockwise (until not possible to select the smaller Sprocket) limits the overall travel of the rear mech in the high gears.

The same procedure can be used to lock-off the larger front chainring too. You can usually lock-off 2 sprockets on a mechanical mech, but cannot lock-off gears on an electronic mech.

Road Racing gearing to British Cycling regulations

There is a huge number of possible component variations to match gear limits, but here is a short list (not an exhaustive list) of the common, more easily achieved set-ups using our stocked components, based on 19mm inner width rims on our HUP CDA30 wheels, being our most popular, due to being legal in CX, Road & Triathlon. We have restricted tyre choice from 23c to 30c, to suit the majority of frame clearances, including the HUP evo and straatrace models…

700c wheels (622mm);

(Recommendations for 1x cranks, especially for riders shorter than 155cm)
U12 (Youth C): 38T chainring x 13t sprocket on 30c tyre using HUP SQT or 2-piece cranks
U12* (Youth C): 36T chainring x 12t sprocket on 23c tyre using HUP SQT or 2-piece cranks
U14 (Youth B): 38T chainring x 12t sprocket on 25c tyre using HUP SQT or 2-piece cranks
U16 (Youth A): 40T chainring x 12t sprocket on 30c tyre using HUP SQT or 2-piece cranks

(Recommendations for 2x cranks, especially for riders 155cm+)
U12 (Youth C): 50T chainring x 17t sprocket on 30c tyre using Croder 1x or 2x cranks
U12* (Youth C): 48T chainring x 16t sprocket on 23c tyre using Croder 1x or 2x cranks
U14 (Youth B): 50T chainring x 16t sprocket on 27c/28c tyre using Croder 1x or 2x cranks
U16 (Youth A): 50T chainring x 15t sprocket on 30c tyre using Croder 1x or 2x cranks

*if you are using the older, road specific HUP straatrace bike with a maximum 25c tyre clearance.

Click the links to find all options for:  CRANKSETS, CHAINRINGS, CASSETTES, WHEELS & TYRES

NEW for 2025 - ‘unrestricted’ gears for U8 and U10

Yep, you read that right. Despite the obvious risk to younger, physically undeveloped riders - they have removed the restrictions for the U8 and U10 categories. We still recommend nothing bigger than a 38T chainring for these categories, on a 700c wheel, but now - it's up to you!

Road wheel selection is critical

Fashions for wider tyres, means wheel widths are increasing, something that isn't helpful for the kids requiring a specific tyre width - modern gravel wheels for example are often not compatible with the tyre width required. The inner width of your wheel, will affect the tyre profile and hence the rollout. You may have a set of wheels already, but if they are too wide - it can easily make your rollout illegal. Our range of HUP wheels are specifically designed to meet both BC and BT rollout requirements (30-35mm deep and 17-19mm inner width) and also the critical UCI 33mm limit for CX tyres - which is why they are so popular, being very lightweight AND legal.

Below is the British Cycling wheel restriction guide...

  • a minimum of 16 and a maximum of 40 spokes
  • spokes can be round, flattened or oval but must not exceed 10mm in width
  • Youth A category will be subject to a maximum rim depth of 40mm from 1st January 2027

Our range of hand-built HUP wheels are fully compliant, with industry-leading weights (but still affordable) including; HUP CDA30, CD35 and TD35 (which are also UCI approved). For all Aluminium and Carbon options CLICK HERE...

Triathlon Racing gearing to British Triathlon regulations

All Tristar/Youth and Junior age categories on Draft Legal (tarmac) events are now gear restricted (which match British Cycling's limits in the table above) they have also introduced wheel restrictions. There is a huge number of possible component variations to match gear limits, but here is a short list (not an exhaustive list) of the common, more easily achieved set-ups using our stocked components, based on 19mm inner width rims on our HUP CDA30 wheels, being our most popular, due to being legal in CX, Road & Triathlon. We have restricted tyre choice from 23c to 30c, to suit the majority of frame clearances, including the HUP evo and straatrace models…

20″ wheels (406mm);

406mm wheels (28c tyres) use 38T chainring and 11t sprocket for TriStart

24″ wheels (507mm);

TriStart*: 32T chainring x 12t sprocket on 47c tyre using HUP SQT or 2-piece cranks
TriStar1*: 34T chainring x 12t sprocket on 47c tyre using HUP SQT or 2-piece cranks

650b wheels (584mm);

TriStart: 30T chainring x 12t sprocket on 25c tyre using HUP SQT or 2-piece cranks
TriStar1: 32T chainring x 12t sprocket on 25c tyre using HUP SQT or 2-piece cranks
TriStar2: 36T chainring x 12t sprocket on 25c tyre using HUP SQT or 2-piece cranks

700c wheels (622mm);

(Recommendations for 1x cranks, especially for riders shorter than 155cm)
TriStart: 36T chainring x 15t sprocket on 25c tyre using HUP SQT or 2-piece cranks
TriStar1: 38T chainring x 15t sprocket on 25c tyre using HUP SQT or 2-piece cranks
TriStar2: 34T chainring x 12t sprocket on 25c tyre using HUP SQT or 2-piece cranks
TriStar3: 36T chainring x 12t sprocket on 25c/27c tyre using HUP SQT or 2-piece cranks

(Recommendations for 2x cranks, especially for riders 155cm+)
TriStar3: 48T chainring x 16t sprocket on 25/27c tyre using Croder 1x or 2x cranks
Youth: 52T chainring x 16t sprocket on 25c tyre using Croder 1x or 2x cranks
Junior: 52T chainring x 14t sprocket on 25c tyre using Croder 1x or 2x cranks

*if you are using the HUP evo24 bike with suitable tyre clearance.

Click the links to find all options:  CRANKSETS, CHAINRINGS, CASSETTES, WHEELS & TYRES

Alternative and popular TriStar1 700c set-up...
For those using a bike for CX and Triathlon gear limited events: 30T chainring and 12t sprocket on 27c tyres on the HUP evo frameset (using the standard 10-speed 11-34t Microshift cassette) gives perfect gearing for CX at this age and accurate Triathlon gearing for the TriStar1 category.

Wheel Selection is critical

BT wheel restriction vary slightly from the BC restrictions - most obviously that carbon is not allowed for the U8 TriStart category. Fashions for wider tyres, means wheel widths are increasing, something that isn't helpful for the kids requiring a specific tyre width - modern gravel wheels for example are often not compatible with the tyre width required. The inner width of your wheel, will affect the tyre profile and hence the rollout. You may have a set of wheels already, but if they are too wide - it can easily make your rollout illegal. Our range of HUP wheels are specifically designed to meet both BC and BT rollout requirements (30-35mm deep and 17-19mm inner width) and also the critical UCI 33mm limit for CX tyres - which is why they are so popular, being very lightweight and legal.

Below is the British Triathlon wheel restriction guide...

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

Our hand-built Aluminium HUP CDA30 wheels are fully compliant, with industry-leading low weight, but still affordable (they are also UCI approved). For all Aluminium and Carbon options CLICK HERE...

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. Our range of hand-built HUP wheels are fully compliant, with industry-leading weights (but still affordable) including; HUP CDA30, CD35 and TD35 (which are also on the UCI approved list). For all Aluminium and Carbon options CLICK HERE...

Juniors (and Seniors)

Will ride on…

EITHER

A standard or traditional wheel as defined by the UCI

  • a rim made of aluminium
  • a rim height of less than 25mm
  • a minimum number of 20 steel spokes which are detachable
  • all components must be identifiable and commercially available

OR

Wheels that are found on the UCI non-standard approved wheel list. Our range of hand-built HUP wheels are fully compliant, with industry-leading weights (but still affordable) including; HUP CDA30, CD35, TD35, CD50 and TD50 (which are also on the UCI approved list). For all Aluminium and Carbon options CLICK HERE...

Other issues to be aware of with BC/BT regulations;

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/TriStar2 usually run 1x single chainring setups, in U14/TriStar3 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. So we developed our extensive range of short cranks, from Square Taper, 2-piece and Croder 1x and 2x cranksets HERE

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 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. Be careful, as when not racing, do they still need climbing gears for where you live? All cassette options are HERE

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) can be re-tested immediately after the race is finished.

CX/MTB/Gravel gearing advice on 27.5" or 29"/700c

Depending on the type of event, there are several options for gearing - popular set-ups listed below. However, your best gearing will always be down to your personal preferrance and the specific event/terrain you are riding...

CX: for U8 to U12 our most popular set-up is a 30T or 32T chainring and an 11-34t or 11-36t cassette. For older riders (U14+) then dependant on rider strength, a 34T to 38T chainring is common. Adults typically use a 40T chainring.

XC: smaller/lighter gearing is common for youth riders upto U12 using 11-34t or 11-36t cassettes (nothing wrong with using larger cassettes, but they do get heavier). Chainring size is always dependant on rider strength but typically a younger rider is best using a 28T or 30T chainring. Older riders (U14+) will often use larger cassettes (11-42t to 11-52t) and a 32T or 34T chainring.

Enduro: larger gearing is more common, for those longer, sustained climbs: 11-42t to 11-52t for example. Chainring size is always dependant on rider strength - typically a younger rider is better off using a small 28T chainring, older and stronger a 32T chainring.

Gravel: very similar to CX gearing, but often using a larger cassette for the sustained climbs and a slightly larger chainring for more flat terrain speed. For example a 34T chainring and 11-42t cassette for younger riders, a 42T chainring and 11-46t cassette for older riders.

Click the links to find all options:  CRANKSETS, CHAINRINGS, CASSETTES, WHEELS & TYRES

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