Mountain bike shifters explained
A mountain bike shifter is the key mechanism for allowing on-the-move gear changes, this is extremely important when riding across technical terrain. Mountain bike shifters still operate by pulling cables to move the derailleurs, forcing the chain to move on to different sprockets/cogs.
What types of shifters are available?
Typically, there are two main types of shifters:
- Twin-lever triggers
- Twist shifters
- Electric shifters
Twin-lever trigger shifters
These are the most common type of mountain bike shifter; they have two triggers, one for changing up a gear and another for changing down a gear. Twin-lever shifters are used by Shimano (Rapidfire) and SRAM (X-ACTUATION and Exact Actuation) who are the main manufactures of mountain bike groupsets.
These are the other main type of shifter that works quite simply by twisting the mechanism that is part of the grip on the handle bar. SRAM make a twist shifter called Grip Shift but there are also other manufactures of this type of shifter.
Electronically controlled shifters
Shimano have now released an XTR Di2 electronic shift system for mountain biking. The battery powered Di2 system ensures that shifts are completely instantaneous - you can also hold down the shifter to change gear across the entire cassette in one motion.
Why are they good?
Shifters are indexed to offer precise shifting, which eliminates gears slipping or being misaligned. There are still some friction shifters available but these now only tend to be used for front derailleurs on lower end bikes. Indexed shifting works really well on mountain bikes as it ensures that the bike stays in the required gear whilst riding across rough terrain.
The benefit of trigger shifters over Grip Shift is the flexibility of positioning the shifter in multiple positions. Trigger shifters can be positioned in multiple places on the handle bar, at multiple angles and also the triggers can be individually positioned.
Twist shifters are limited in where they can be positioned on the handle bar but you get various grip length options. This is a very clean and simple looking set up and has gear indicators to show you what gear you are in at a glance. Trigger shifters also have a option for a gear indicator but are less common.
How do I choose?
When choosing what type of shifter would be best for your mountain bike it very much depends on your personal preference and also preferred groupset. Determining what groupset you fit to your mountain bike may limit your shifter options, for example, Shimano only uses under bar trigger shifters in their latest range of shifters.
SRAM however still offer both options, the under bar trigger shifter and also different length Grip Shift shifters. Typically it is not recommended to mix different brands of drive terrain components even if they have the same amount of gears.
The best way to choose your mountain bike shifter is to try them both out before purchasing to see which one you find more comfortable. Twist shifter sometimes become hard to use when the grip gets sweaty or muddy but when riding with gloves this shouldn’t be an issue.