If it is possible to go beyond the existing GEAR RANGE, can the transmission system enable us to conquer more terrain?
The theoretically exposition of gear ratio, which mentioned in previous article, is about the force transmission relationship between output torque and forward speed of the drivetrain system. As for actual riding, gear ratio directly associated to the terrain. The major concern of cyclists is that what gear ratio to choose according to how slopy the route is.
GEAR RANGE is the multiple percentage of the lowest gear ratio to the highest gear ratio. In other words, the wider the gear range is (when the lowest ratio is lower, and the highest ratio is higher), the more terrain you can cope with. Subsequently, there would be fewer restrictions on your athletic performance.
The average gear ratio of mountain bikes is about 0.5-2.5; and that of road bikes is about 1.2-6. The reasonable gear range is approximately 500% due to some limitations: if the tooth difference between sprockets is too large, the bike would become hard shifting; Also, the number of sprockets can’t be too much since the size of rear fork and hub has its limits, changing these two has a significant impact on other components; Lastly, the gear ratio of chainring to sprocket will affect the stability of shifting, which interrelates with total capacity and the chainline.
It has been said that chain drive system is the best compromise of all three drivetrain systems. The boundedness of it can be explained from the aspect of gear range; The maximum gear range of chain drive system might be around 500%. From the theoretical perspective of gearing, think about how much gear range is suitable for all-terrain cycling? If there is a transmission system that has gear ratios from 0.5-6, the bike might be able to handle all kinds of trails. Would it be possible for the transmission system to have 1200% gear range?