Mountain Bike Gear Explained. The highest, or biggest gear on a bicycle is achieved by combining the largest. Going from "easier" gears to "harder" gears is called "upshifting", and the reverse is called "downshifting".
In a derailleur system, the gear ratio is altered by increasing or decreasing the size of either the front chainring or the rear. Just remember that larger gears at the rear mean easier pedalling but more torque, and larger gears at the front mean harder pedalling but more speed. For the front chainrings, bigger chainrings equal a harder gear.
Due to this, mountain bikes use specific gear ratios that are best suited to the rugged terrain, and generally lower average speeds compared to other cycling forms.
On mountain bikes, cyclo-cross and gravel bikes, single chainring set-ups have become increasing common.
Gear Ranges on Bikes Broadly speaking, mountain bikes have lots of low gears so you can climb steep hills more easily, while road bikes have more higher gears to boost top-end speed. A Shimano XT rear derailleur on a mountain bike A bicycle gearbox with chain tensioner Bicycle gearing is the aspect of a bicycle drivetrain that determines the relation between the cadence, the rate at which the rider pedals, and the rate at which the drive wheel turns. A high gear, sometimes referred to by cyclists as a 'big gear', is optimal when descending or riding at high speeds.