How to index Shimano Di2 gears

If gears are jumping on the cassette or making a noise, it usually means that the derailleur is unaligned with the cogs and needs adjusting.

Start by shifting into the fifth largest sprocket, which is the fifth one down from the top.

Press and hold the function button on the rear derailleur until the LED light on the derailleur turns yellow. This indicates that the system is in its adjustment mode.

The derailleur now needs moving to align it with the cog on the cassette. You can do this by pressing the gear levers. The gear lever that shifts into a harder/smaller cog will move the derailleurs outwards, away from the wheel. Clicking the gear lever that shifts to an easier gear will move it inwards towards the wheel.

Pedal the bike as you’re doing this and keep adjusting it until everything is running smoothly and there are no unwanted noises.

Hold the button on the rear derailleur once more to exit adjustment mode.

Test to make sure everything is running smoothly. If it isn’t, you’ll need to repeat the process and make more adjustments to the derailleur.

If you’re struggling to shift between the small and large chainrings or vice versa, or the chain is rubbing against the front derailleur, it will need adjusting.

To do this, start by shifting into the largest chainring and the smallest cog on the cassette.

Press and hold the button on the rear derailleur until it turns yellow. This signals that it is in adjustment mode (when in adjustment mode, both of the derailleurs can be adjusted).

Use the gear levers to adjust the position of the derailleur. The lever that switches to the large chainring will move it outwards, and the one that switches to the small chainring will move it inwards.

To start, adjust the derailleur so that the outer plate isn’t touching the chain. There should be a roughly 1mm gap.

Exit adjustment mode by holding onto the button on the rear derailleur and then shift to the largest cog on the cassette.

Enter adjustment mode once again and then use the levers to adjust the derailleur so that the inner plate of the derailleur is roughly 1mm away from the chain.

Repeat the process by exiting adjustment mode and shifting to the small chainring and the largest cog on the cassette.

Then use the lever to adjust the derailleur so the inner plate is around 1mm from the chain.

Exit adjustment mode for one final time and then run through the different gear combinations on the bike, making sure everything is running smoothly.