It is more common to see complete groupsets on road bikes. When it comes to mountain bikes, however, brands usually mix and match parts from various groups – and in some cases different brands – to suit the bike’s intended use and meet a specific price point. Here are the Shimano Mountain Bike Components levels explained.
Components of a Shimano Mountain Bike
- Mountain bike crankset
Shimano offers its XT group in versions with one, two and three chainrings. Mountain bike cranksets can be divided into three categories by their number of chainrings.
The first is the triple – the old classic. As the name implies, it consists of three chainrings, the largest often being a 42- or 44-tooth outer ring.
Cranksets with two chainrings overtook the triple as the most popular mountain bike crankset when SRAM and Shimano introduced 10-speed drivetrains. Double cranksets offer a narrower gear range with less overlap than a triple.
The most significant trend in mountain bike drivetrains over the past five years has been the movement toward wide-range drivetrains with a single chainring.
- Mountain bike bottom bracket
Different frames use different bottom bracket systems, including threaded (left) and press-fit (right).A crankset won’t get you very far without bearings to spin on. These bearings are pressed or threaded into the mountain bike’s bottom bracket shell.
- Mountain bike cassettes
Shimano’s widest range 12-speed cassette offers a 10-51t spread, while SRAM offers a 12-speed group with a 10-50t range. Cassettes come in a wide range of sizes and speeds. Like the crankset, cassette choice is often determined by the bike’s intended riding style and price.Mountain bike cassettes can be found in 7- through 12-speed versions. They are usually referred to by the smallest and largest cogs to provide an indication of the total range, e.g. 11-32t or 10-50t.
- Mountain bike chains
The groupset brand and the number of gears dictate the type of chain you need. In general, as the number of gears increases, the spacing between the cogs shrinks and so the chain becomes narrower as well. More expensive chains often have smoother, more durable and corrosion-resistant coatings and save weight with hollow links and pins. With that in mind, chains are the first part of a drivetrain to wear out, so it’s often best to invest in a mid-level chain.
- Mountain bike derailleurs
Derailleurs are the components that move the chain between cogs on the cassette and chainrings on the crankset. Each brand offers its own design, but the principle is generally the same. Cables are no longer the only way to control derailleurs. Shimano offers electronically actuated derailleurs on XTR Di2 as well as XT Di2, which use electrical wires connected to the shifter(s). SRAM’s AXS groupsets are completely wireless.
- Mountain bike shifters
As previously mentioned, shift levers are used to operate a bicycle’s derailleurs. Shimano and SRAM use different designs, and while they all shift gears, they each have a particular way of doing it.
These are the various Shimano Mountain Bike component levels.