To be able to shift gears with a mountain bike, a good derailleur is indispensable. Today, mountain bikes are increasingly equipped with one chainring at the front instead of three. As a result, there is often only a rear derailleur and no front derailleur. In this article I will tell you everything about adjusting a derailleur of your MTB.
Why adjusting an MTB derailleur is important
A derailleur ensures that the chain of your mountain bike can be easily changed to different chainrings. In addition, a rear derailleur also ensures that the chain remains properly tensioned. If you miss the derailleur of your MTB, you have of course adjusted it properly!
Important reasons to properly adjust the derailleur:
- Comfortable shifting
- Less wear MTB chain and chainrings
- Chain off less quickly
- Less power loss
Adjustment options of the mountain bike derailleur
A derailleur can look a bit complicated. All screws and many small parts. Yet it is less exciting than it all seems. Broadly speaking, there are three different adjustment ways:
- Limit screws: you can adjust the derailleur more to the left or right with the limit screws. Often the limit screws are marked with an H (highest gear) and L (lowest gear).
- Adjusting screw: The adjusting screw allows you to adjust the vertical distance of the derailleur.
- Cable adjustment screw: there is an adjustment screw on the gear cable, with which you can lengthen or shorten the cable.
In the picture below you can see where the limit screws (1) and the adjusting screw (2) are located.
Adjusting the derailleur MTB: step-by-step plan
In many cases you can already properly adjust the derailleur using the cable adjustment screw. Not enough? Then grab the necessary Allen keys (size Allen key depending on your derailleur).
Follow the steps below to adjust the mountain bike derailleur.
- Make sure the rear wheel is off the ground
Use a separate mountain bike stand or hang your mountain bike so that the wheel can turn loose and you have enough working space.
- A derailleur with clutch? Then turn it off during adjustment!
A clutch ensures that blows are absorbed, but this can prevent adjustment. So turn it off temporarily.
- Turn the adjusting screw all the way in so that there is no more tension on the gear cable
Unscrew the setscrew completely with the Allen wrench.
- Tighten the H adjustment screw until the derailleur is directly under the smallest cog
If the adjusting screw is too loose,
- Using the MTB pedals, manually turn the cage to the largest cog
Now you can adjust the L adjustment screw when the derailleur is directly under the largest cog. If it is too loose, the chain can shoot into the spokes. If it is set too far, it simply won’t reach the last cog.
- Now turn the adjusting screw of the gear cable (near the handlebars) all the way in
If the gear cable runs behind the blade, retighten the adjusting screw at the derailleur.
- Now shift to a higher gear and turn the crankset around
Is he starting to rattle? Then there is not enough tension on the cable. Adjust the adjusting screw at the top of the cable until it shifts to the next gear.
- Then shift back to the smallest cog.
Now retest all gears while spinning the crankset. Does it switch on and off silently? The cable tension is then correctly adjusted.
- Now we are going to adjust the vertical distance of the derailleur, with the B-adjusting screw (B tension screw)
Now set the gear to the highest cog. Keep about 1.5-1.6 centimeters vertical distance (from the derailleur cage to the largest cog).
- Put the clutch back on if you had turned it off in step 2!
The MTB rear derailleur is now properly adjusted!
Frequently asked questions about mountain bike gear adjustment
If you notice that switching to different gears with your mountain bike is no longer smooth, you may have to readjust your MTB derailleur. A well-adjusted derailleur makes shifting easier and ensures that other mountain bike parts (including the sprockets) wear less quickly.
The mountain bike derailleur may look very complicated, but adjusting it is not that difficult if you know what to do. With the step-by-step plan on this page you can ensure a well-adjusted mountain bike derailleur step by step.
You need allen keys for adjustment. In many cases it concerns an Allen key 2 or 2.5 and an Allen key 4. However, this depends on the type of MTB derailleur you have.
By checking the adjustment of your derailleur every now and then, you can avoid major adjustments. Are you going to clean the bike gears? Always check the adjustments afterwards.