Choice of transmissions.
With derailleur gears a cyclist can choose from a large number of gears. The gears on the bicycle have to be chosen so that a large number of gears will also be utilized.
Derailleur gears are mainly used on bicycles for sporting use. The purpose of the large number of gears is, that the athlete under all conditions can deliver maximum power. The cyclist will want to cycle at all times with the same cadence. For the determination of the gear ratios must be known when is cycled under what circumstances, and the speed the cyclist will reach approximately under those circumstances.
The main factors have been:
- Wheel Size.
- The capacity of the rear derailleur.
- The capacity of the front derailleur.
- The number of available gears (chainrings x rear sprockets).
It will be obvious that choosing the appropriate sprocket combination is not a simple choice.
A customer who uses the road bike to ride on plane trips will not run with such large differences in maximum and minimum speed. Steps should be small and tailored to the average speed that drives the cyclist. A customer who ride in the mountains on vacation will drive significant differences in maximum and minimum speed. In addition, the customer mainly perform strenuous exercise while climbing. On flats and in the downhill he bikes with less effort. The gears must also be adjusted so that the customer has the best possible choice when climbing. In the field, the difference between maximum and minimum speed is very large, while the maximum speed will generally be slightly lower.
Before choosing the right gear, the following general guidelines can be given:
- Install rear sprockets with small differences in order to prevent the differences between each step to be large.
- Fit for chainrings with such a difference that the heaviest gear that can be switched with the small blade matches the lightest gear that can be switched to the large chainring.
- Install preferably a triple chainring if someone goes biking in the mountains. By use of a small cover sheet can be kept small behind the steps. Especially during hard climbs the cyclist will deliver a lot of power and want to have access to a number of different transmissions. When installing a triple crankset is overlap gears unavoidable because the difference in size between the chainrings will be limited by the capacity. Choose the difference between the largest and smallest chainring so that just falls within the maximum capacity of the front and rear derailleur.
Table 2 through 8 are a number of examples for different gear ratios for driving on flat roads in the Netherlands, in the mountains and terrain. It is clear that a triple crankset for a large total range of gears is required.