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Bicycle Chain

Bike & Race
Set-Ups 

Bike Set-Ups for Junior Racing
Navigating junior ‘gearing’ and ‘roll outs’ can be a confusing and time consuming process for parents new to junior cycling. .

A bike’s rollout is the distance the bike travels over one complete pedal revolution and is measured in metres. Road bikes have multiple gears and hence multiple rollouts.

For racing in Australia a bike’s rollout is measured as the largest rollout available at presentation to officials at the race meet. This is when the chain is on the largest available chain ring and the smallest available sprocket on the rear cassette.

To race on the road at junior level the following rollouts are required.

U11 = 5.5m (approximately 42 tooth chainring/16 tooth cog)
U13 = 5.5 m (approx 42/16)
U15 = 6.0 m (approx 42/15)
U17 = 7.0 m (approx 46/14)
U19 = 7.93 m (approx 52/14)
Most off the shelf bikes will roll over these limits and have to be adjusted to conform to race standards. Rollouts can be achieved by:

locking out (disabling) one chain ring (front) and/or one or two of the smallest sprockets onthe cassette (rear) by adjusting the front and/or rear derailleurs; or
fitting a combination of chain rings and sprockets that achieve the desired maximum rolloutwithout disabling either of the derailleurs. That is, the full set of gears on the bike are available.
Lockouts are the most common way of achieving a legal rollout and this method is allowed at local race meetings. However, at Road National lockouts are not allowed and method 2 above has to be used.

To Calculate a Rollout on a Road Bike

There are 3 variables that need to be measured.

  1. The number of teeth on the largest chain ring (see photos).

  2. The number of teeth on the smallest sprocket on the cassette (see photos).

  3. The rear wheel size (see photos). Most wheels on recent road bikes have a standard diameterand the main variable is the width of the tyre (distance between the wheel rim and the outer tyre edge). This is usually written on the side of the tyre and must be used in calculating a rollout.

 

Enter the figures into an online calculator to find a rollout. There are several online calculators and they don’t always give the same result. AusCycling Calculator

Also, beware that calculated rollouts rarely equate to real-world rollouts. If you calculate your bike to be very close (1-5 cm?) to the legal rollout be aware that the bike could roll over the legal limit once you have made the adjustments.

Cycling Australia’s Technical Regulations specific to Juniors
3.6 EQUIPMENT RESTRICTIONS

3.6.01 Gearing – rollout distances

For all junior categories, male and female, the following maximum roll out distances shall apply for Road Events & Track Events

Junior U19 7.93 metres *
Junior U17 7.0 metres
Junior U15 6.0 metres
Junior U13 5.5 metres
Junior U11 5.5 metres
*When competing in junior only events

3.6.02 If, for whatever reason, a junior rider has been granted approval to compete in a higher age division event, the maximum roll out distance applicable to the rider’s age division must be maintained, except U19.

3.6.03 To restrict the roll out distance mentioned above, blocking off may be permitted by the adjustment of the derailleur or other means. There shall be no blocking off of gears allowed at U15, U17 or U19 Road National Championships.

3.6.04 For all junior categories up to and including JM17 – JW17 the following equipment restrictions will also apply for road and track competitions.

Handlebars shall be of a standard or “Classic” style. However bolt on handlebar extensions shall be allowed for JM15, JW15, JM17, and JW17 in the individual pursuit, team pursuit, and road and track time trials only.
No modification to the extension shall be allowed. Gear and brake mechanisms must not be placed on the extensions.
For all events, wheels must have at least 16 spokes. The rim shall exclude the use of composite fibres.
Only high-pressure detachable tyres and tubes shall be used. A detachable type tube means the tube is detachable from the tyre casing.
Such high-pressure tyres shall be beaded.
Suggested Junior Gearing

Division    Roll Out    Chainring & Sprocket Combinations
Under 11    5.5M    42 x 16
Under 13    5.5M    42 x 16
Under 15    6.0M    42 x 15 (38/39 x 14)
Under 17    7.0M    46 x 14
Under 19    7.930M    52 x 14
The ‘roll out’ distance is the distance travelled by the bicycle with one revolution of the crank, irrespective of the sizes of the chainring, sprocket, and wheels. This is the method employed by Commissaires at events. The Commissaire will shift your bike into the largest gear available, the biggest chainring on the front and the smallest gear on the back. The suggested combinations are usually very close for the rollout with normal 700 wheels x 23 mm tyres, but can vary with tyre sizes and pressure. There are various other configurations by which the gearing for these rollouts can also be achieved.

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