A chainset is part of the drivetrain on a bike. It connects via the chain (or belt in some cases) to the drive wheel of the bike. The chainset rotates using the bottom bracket as a support and housing. When the chainset travels in a clockwise direction, this provides the power to move the bike forwards.
The cranks are the equivalent to an accelerator pedal in a car, or throttle on a boat. To start the wheels turning, you need to turn the cranks. Chainsets need to be strong and able to withstand the motions and stresses cycling puts it through. Aluminium alloys and carbon are the most popular materials for the crank arms.
How do I choose?
Chainsets come fitted with chainrings, but cranksets do not. So this is a good starting point of what to look for. If you are looking to upgrade and keep the same size chainrings, then check your current chainset for markings. Your chainrings are likely to have a stamp or writing on them with the number of teeth each has, or you can simply count them.
Crank length is usually indicated on the inside of each crank close to the threaded hole for the pedal. On this image you can see 172.5, that denotes it is a 172.5mm crank length.
Choosing your crank length is a wide open debate on what is best for you and your leg length, there are many articles that explain different theories behind crank length selection. Road chainsets vary from 165mm upto 180mm, in 2.5mm increments. If you are in any doubt, the Wiggle customer service team are able to offer guidance based on leg length or if you require advice.
Chainsets can fit different bottom bracket types, it's important you choose the correct chainset for your bottom bracket/frame type. Your bottom bracket model can be anything from square taper to BB386. Wiggle's customer service team are happy to help you with any questions or queries you may have.
Compact and standard chainsets A chainset is described as a compact model when it has 34/36teeth inner chainring and a 50teeth outer chainring fitted. Compact chainsets are a great alternative to a triple chainset as they offer a good wide ratio of gearing and provide a good chainline, thus giving increased chain strength. Compact chainsets are ideal for most sportives where the terrain is undulating and the need for a large top gear not necessarily required.
Standard chainsets are fitted with 39/42teeth inner and 52/53teeth outer chainrings. These chainsets are for racing or if you are comfortable with climbing. The gear ratios are higher on standard chainsets and closer than those found on a compact or triple chainset.
Once a popular site on many sportive bikes, triple chainsets are not as popular anymore. A triple chainset features three chainrings. The middle and outer chainrings are similar ratios to those found on compact or standard chainrings. The big benefit of a triple chainset is that it has a very small inner chainring so offers a very low gear. They are a great option for touring bikes or very mountainous cycling.
Mountain bike chainsets
Triple chainsets paired with a 9 or 10 speed cassette are still very popular with a wide range of riders. If you spend hours in the saddle tackling steep climbs then a triple chainset is ideal in terms of versatility. If your riding is more about descending, then a double or single chainset is more suitable in relation to gearing and using a chain retention device.
Double chainsets (2x10) paired with high ratio 10 speed cassettes are now hugely popular due to their lightweight compact design. Double chainsets offer you a wide range of gears to tackle climbs and descents. They are also compatible with most chain retention devices and this makes them appeal to aggressive riders.
Single chainsets (1x11) In 2013 SRAM launched "XX1" the first production 11 speed chainset. This incorporates a single chainring paired with an 11 speed high ratio cassette. This system offers you the very latest in chainset technology as it provides an incredibly wide range of gearing on a simplified drivetrain.