Gear restrictions apply to all junior cyclists in events conducted under Cycling Australia regulations on the road and track.
The restrictions referred to is the distance one revolution of the crank arm will propel the bicycle, this is known as the 'roll out'.
All competitors are required to satisfy a roll out for all junior events.
All juniors will need to present their bikes to the commissaire prior to the event to be rolled out. Bikes can be rolled out after the event at the commissaires discretion.
|Division||Roll Out||Chainring and 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 cycle with one revolution of the crank, irrespective of the sizes of the chainring, sprocket and wheels. This is the method employed by Commissiares at events. The Commissaire will shift your bike into the largest gear available, the biggest chain ring on the front and the smallest gear on the back. The suggested combinations are usually very close for the roll out 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 roll outs can also be achieved.
Please note that blocking off gears is not permissible in a State Championships. The only exception to this is that U/13 riders are permitted to block off.
To begin, make sure the drive train is clean, freshly oiled, and shifting properly. Put the chain onto the appropriate rear cog so that the expected rollout will be met. Locate the 3 adjusting screws on the back of the rear derailleur. The upper screw is called the B-screw and it generally does not require adjusting. The lowest screw adjusts the possible range of the derailleur when it is on the largest rear cogs. Stay away from this one as turning it the wrong way can lead to the spokes playing expensive games with the derailleur.
The middle screw is the high range adjuster. Turning it in (clockwise) will limit the range of the derailleur and hence, tend to prevent the chain from engaging smaller gears. Turning it out (CCW) allows more range and will therefore allow engagement of smaller gears. To make the adjustment, start screwing the high range adjuster in (CW) until you just feel it start to tighten up. From this point, you’ll probably want to turn it another ½ turn. Now, downshift the gear lever so that it would normally allow engagement of the 13T cog and turn the crank. If it drops down to the 13T, you haven’t turned it in far enough. Make your adjustments in ½ turn increments until you just keep it in the 14T. Turn it too far and you’ll notice that the chain either jumps into the 15T or tend to skip upwards towards it. If this happens, turn the screw back out a little.
It's important to keep in mind that a 15T cog is the smallest cog that will meet the restriction with a 53T chainring. The above description assumes a 52T chainring.