Most people are familiar with the term ‘clutch’ when referring to cars, but clutches can actually also be a part of a bicycle.
Mainly found on mountain bikes, a bicycle clutch is a mechanism located on the rear derailleur. A bicycle clutch works by dampening the pivot point at the top of the derailleur, so the arm does not bounce around potentially causing damage to your frame or resulting in the chain unshipping completely.
What is the purpose of a Bicycle Clutch?
The purpose of a bicycle clutch is to retain chain tension by restricting the derailleur’s movement. When riding over rough ground, the weight of the chain makes a standard derailleur bounce up and down. This movement can lead to a distracting chain noise or even worse result in the chain falling off the chainrings completely.
A clutch mechanism helps to keep the chain taught, removing the possibility of your chain slipping or dropping from the chainrings. Shifting through the gears can feel stiffer than using derailleurs without a clutch. However, most clutch rear derailleurs have a similar design and come with a switch to disable the clutch when it is not needed. No matter which groupset you are running, they will use the same internal mechanism, but the design may differ slightly. On the higher end groupsets, you will have the ability to adjust the tension to reduce or increase the stiffness of the clutch when switched on.
Do Bicycle Clutches only exist on Mountain Bikes?
Interestingly, Shimano has tried to bring this technology to the road bike market with the Shimano RX derailleur, although this may be a worthy investment for the pros that are tackling the cobbled classics, most road cyclists will not see any real benefit from installing a clutch system on their rear derailleur.
When you are looking to upgrade your mountain bike and invest in a new groupset or rear derailleur, it is worth spending a little extra to get one with a clutch. Leaving you to focus on staying upright and beating your PB on your local trail, rather than worrying about if your chain is going to slip.