Very few things are as irritating as a noisy, jumpy drivetrain. Suddenly you struggle to get the power to your back wheel and can’t shift into the right gear. But since we are here to help we will show you how to dial in your mechanical drivetrain properly to avoid unpleasant surprises.
Many different factors can affect the shifting performance of your bike. A worn-out, chain can slip over the sprockets and ruin your ride. We’ll tell you how to assess and change your chain in a separate tutorial.
For this specific tutorial we assume that your groupset is correctly installed and that crucial parts such as cables and mech-hanger are in a good nick.
Gear adjustment is pretty much the same for all manufacturers. Product specifics can be read in the manual.
- Allen keys
Instructions Part 1 – Indexing the gears
We recommend shifting into the big chainring for indexing. This way you straighten up the rear-derailleur and will find it easier to check the alignment.
Step 1: check and adjust the limit screws on the rear-derailleur. These two small screws are usually marked with H and L, where H stands for High and L stands for Low. The first one allows you to set the limit of the smallest sprocket (largest gear) and the second one sets the limit of the largest sprocket (smallest gear).
To perform the first adjustment use the H screw –before you start shift into the smallest sprocket. The jockey wheels should now be vertically in line with the smallest sprocket. If that’s not the case, get them into the right position using the H-screw. By turning the limit screw clockwise you’ll move the derailleur-cage towards the wheel and by turning it anti-clockwise you’ll move it away from the wheel.
Now you have to set the upper limit. To do this shift to the largest sprocket first. The jockey-wheels should now be aligned with the largest sprocket. If that’s not the case, get them into the right position using the L-screw. By turning the limit screw clockwise you’ll move the derailleur-cage away from the wheel, by turning it anti-clockwise you’ll move it towards the wheel — basically the opposite as with the H screw!
Tip: If the chain doesn’t jump into the biggest sprocket you have to check your cable tension. We explain how you do this in the next step.
If your chain jumps into the largest sprocket without any problems, you can skip this section. If you can’t shift to the biggest sprocket you have to increase the tension of your shifting cable by adjusting the barrel adjuster on the rear-derailleur – by turning this counter-clockwise you’ll increase the tension. Now the chain should jump onto the biggest sprocket and the upper limit screw can be adjusted as described in the previous step.
Quick upper limit-screw check: shift to the smallest sprocket and push the rear-derailleur to the largest sprocket by hand without using the shifter. Check again that the jockey wheels are now in line with the largest sprocket.
Now that both limit screws are set, you don’t need to worry about them anymore. Now it’s time to index the shifting. Before you do this, shift to the smallest sprocket and up a gear. If the shift performs smoothly you’re done for now. But if the chain doesn’t jump onto the second sprocket you have to increase the cable tension. To do this turn the barrel adjuster counter clockwise until the chain jumps onto the second sprocket.
Repeat the previous step by jumping from the second to the third smallest sprocket. If this happens smoothly nothing else needs to be adjusted. If the chain doesn’t jump into the second sprocket smoothly you have to increase the cable tension. To do this turn the barrel adjuster anticlockwise until the chain jumps onto the third sprocket.
You can now shift through all gears and check whether your drivetrain works smoothly. Take your time to assess the shifting performance accurately. If all gears shift smoothly repeat the procedure with the small chainring.
Most frequent issues & troubleshooting:
- If the gears only shift well on one part of the cassette check the mech hanger and see if it’s bent.
- Loose cables will most likely affect the shifting performance. If you installed all cables properly but still can’t get your drivetrain to shift smoothly, try replacing all cables and cable housings.
- If you reach the limit of the barrel adjuster while increasing the cable tension, loosen the adjuster on the rear-derailleur and tighten the cable by hand or using some pliers.
Instructions Part 2 – Adjusting the front-derailleur
Dialling in your front-derailleur is generally easier than adjusting the rear-derailleur. All you have to do is adjust the upper and lower limit-screws.
Just like with the rear-derailleur you can set the limit of the front-derailleur using the H and L limit-screws. Once again, the H screw (High) sets the upper limit, only this time on the big chainring. The L screw (Low) on the other hand sets the lower limit on the small chainring.
In this first step we’ll show you how to adjust the lower limit of the front-derailleur. Before you do this put the chain into the smallest chainring and largest sprocket. When the inner guide-plate is about 1 mm from the chain, the front derailleur is correctly positioned. If the guide and the chain are too close together they will touch and make a grinding noise. If the guide plate is too far away from the chain, the chain may fall off the chainring.
Now it’s time to adjust the upper limit of the front derailleur. Before you do this put the chain into the biggest chainring and smallest sprocket. When the outer guide plate is about 1 mm from the chain the front-derailleur is correctly positioned. If the guide plate and the chain are too close together they will touch and make a grinding noise. If the guide plate is too far away from the chain this could fall off the chainring.
In the next step you will check the shifting performance from small to large and from large to small chainring. If the gears shift smoothly you don’t have to adjust anything else. If the gears still don’t shift properly you have to adjust the tension of the shifting cable.
If the shift from the small chainring to the large one doesn’t happen smoothly, the tension of the cable is too low. To increase cable tension turn the barrel adjuster counter-clockwise.
If the shift from the large chainring to the small one doesn’t happen smoothly the tension of the cable is too high. To reduce cable tension turn the barrel adjuster clockwise.
Most frequent issues and troubleshooting:
- If your drivetrain keeps making noise despite correct installation the front-derailleur might be fitted at an angle or even bent.
- Loose cables will affect the shifting performance. If all cables are properly installed and you still can’t get a smooth shifting performance you should replace all cables.
- If you reach the limit of the barrel adjuster while increasing the cable tension, loosen the adjuster on the rear-derailleur and tighten the cable by hand or using pliers.
Did you enjoy this article? If so, we would be stoked if you decide to support us with a monthly contribution. By becoming a supporter of GRAN FONDO, you will help secure a sustainable future for high-quality cycling journalism. Click here to learn more.
Words: Manuel Buck Photos: Valentin Rühl