Adjust a Shimano Nexus or Alfine hub
On a bike with an internal gear hub, the adjustment comes down to one move: line up two yellow marks, in the reference gear, with the adjuster on the shifter. If gears skip or one of them "slips", that's where to start.
What you need
- None: the barrel adjuster is on the shifter
- A 10 mm spanner or a hex key, if the cable needs re-tensioning at the hub
- A torch
Why
An internal gear hub (Shimano Nexus, Alfine) hides the gears inside the rear wheel. The shifter cable turns a part on the side of the hub, the cassette joint. If the cable goes slack, the selected gear no longer engages cleanly: it skips, clunks or slips under load. Two yellow marks, visible in a small window, show whether the adjustment is right.
Which reference gear?
| Hub | Reference gear |
|---|---|
| Nexus 7-speed | 4th |
| Nexus 8 and Alfine 8 | 4th |
| Alfine 11 | 6th |
The marks
In the window (1) of the cassette joint, on the right-hand side of the hub, two yellow marks face each other: one on the fixed part (2), the other on the part that turns with the cable (3). Shimano puts these marks in two places on the cassette joint: use whichever you can see best. Some models have two pairs of marks (dots and lines): line up dots with dots, or lines with lines, without mixing them.
Steps
1. Shift into the reference gear
Depending on your hub (see the table), shift to 4th or 6th gear. Turn the pedals backwards a little, or ride a few metres, so the hub engages.
2. Find the yellow marks
Look at the cassette joint with a torch. Crouch down on the right-hand side of the bike: the window is small, it can take a couple of tries. The marks may be a bit dirty: a wipe with a rag helps.
3. Line them up with the adjuster
Turn the barrel adjuster, where the cable leaves the shifter, until the two marks are exactly lined up. Turn it a click at a time while watching the window: it's easier with two people, one on the adjuster, the other watching the marks.
4. Check the adjustment
Shift into 1st, then back to the reference gear, and look again: the marks should still be lined up. If not, correct by one click and repeat.
5. Test while riding
Go for a short ride and use every gear, pedalling firmly. No gear should skip or clunk under load.
If the adjuster isn't enough
If the adjuster runs out of travel before the marks line up, the cable is too slack:
- Set the adjuster back to the middle of its range.
- On the cassette joint, loosen the bolt that clamps the cable, pull the cable slightly to tension it, and tighten.
- Start the adjustment again from step 1.
Common mistakes
- Adjusting in the wrong gear: the adjustment only works in your hub's reference gear.
- Shifting while pushing hard on the pedals, then blaming the adjustment.
- Ignoring the cable: a rusty cable or crushed housing makes any lasting adjustment impossible.
What next
An internal gear hub needs little maintenance, but it does need some, at a bike shop or with the Shimano kit:
- Nexus and Alfine 8: a periodic oil bath (the internals are dipped in Shimano maintenance oil), as often as the manual says;
- Alfine 11: an oil change with its own oil, specific to this model. A first change early on, around 1,000 km, flushes out the fine particles from bedding in; then at regular intervals. Another oil can damage the seals. The logbook reminds you if you choose an oil-bath hub. The chain is looked after like on any bike: clean and lube your chain.
Sources
This guide was checked against the following documents:
- Shimano, Nexus and Alfine dealer manuals ("Adjusting the cassette joint")
- Ride Your Bike, Shimano internally geared hubs (maintenance and oil)
Values vary between models: your part's manual always takes precedence.