Adjusting Di2 Alfine 8?

[LittleWheelsandBig]

A friend has an ebike with Di2 Alfine 8 gearing that is having intermittent shifting issues between Gears 5-6 in both directions.

I have not played with Di2 hub gears before and most of the information on the net (remarkably little) doesn’t refer to the Alfine 8 version. I understand that the Di2 actuator is the same for 8sp and 11sp hub gears. The Shimano dealers manual doesn’t give any useful troubleshooting advice, effectively saying “tweak this and see if it makes better, otherwise tweak it the other way and see.”

Because this hub has the same issue changing up and down, I don’t think this adjustment will solve things and, if unlucky, may make it worse. The tweaking is effectively the same as tightening or loosening a gear cable. There is also an adjustment for speed of shifting but I don’t know what is the best shift speed for an ebike.

Does anybody here have experience with diagnosing and adjusting Di2 hub gears?

[alexb]

Alfine hubs have a design weakness between gears 5 and 6 that can allow them to partially strip the planetary gears resulting in gear skipping in one or other gear.
My first hub failed this way.
The newer ones with the spirally cut gears should be better, but this might actually be what you're experiencing.

[BFC]

When I did some research into Alfine hub gears a few years ago there were "original" versions and updated versions available (very slight change of part numbers). The updated versions having "improved shifting for e bikes". The issue with e bikes is that they tend to maintain drive torque during gear shifting. Finding the hub part number may reveal which version you are working with. Helical gears run quiter than straight cut but also generate end thrust which needs to be contained within the mechanism.
These hubs do like a regular oil change, it may be that simple, but inspect the oil that comes out for metalic particles (a magnet helps find bits of gears in the oil). Hopefully the wheelbuilder/robot paid attention to the location of the service plug when lacing the wheel!

The gear sets and selector mechanism within the hubs are the same for Di2 and cable controlled versions - the difference is the selector shaft return spring which is built into the cable controlled hubs is deleted for the Di2 version. In theory a cable controlled hub can be upgraded to Di2 by dismantling and removing the spring. Spare parts (gear clusters etc) did seem to be available when I was looking, but that assumes you can get into the hub with the tools you have available, and of course get it back together.

To update and adjust anything Di2 the Shimano software and adaptor are the way to go. A pain to use and bloody slow but the only way to talk to the software/firmware world of Shimano modules at a sensible level. The Di2 actuator module (and its firmware) do not know which version of hub its controlling until someone configures it, the actuator may be a dumb module with the intelligence being elsewhere in the system.

[Wobbly John]

I thought you should use grease for the Alfine 8 as oil leaks out over the disc brake?

Mine had grease in it and I regreased it earlier in the year.

The Alfine 11 has oil.

[BFC]

I was researching the Alfine 11 at the time, and assumed the technology was the same.

[PhilO]

I thought you should use grease for the Alfine 8 as oil leaks out over the disc brake?

Mine had grease in it and I regreased it earlier in the year.

The Alfine 11 has oil.

The Alfine 8 is grease-filled, but relubrication is done by dipping the innards in an oil bath.  I've done this several times now, to the point where I imagine that most of the grease is gone, but never had issues with oil escaping onto the disc. Just make sure you let it drip for a bit before reassembling.

See: https://muddymoles.org.uk/reviews/stripping-and-an-oil-bath 

^Not my description.

I've also experienced the loss of gears 5/6 as mentioned by alexb, and that was my first thought too.  Stripping and dipping helped, but it was never quite the same and that hub got retired.

[mzjo]

I thought you should use grease for the Alfine 8 as oil leaks out over the disc brake?

Mine had grease in it and I regreased it earlier in the year.

The Alfine 11 has oil.

The 500 series hubs (mine was 501, think they call it S-501) and the Nexus hubs have grease in them. Shimano recommend refreshing the grease with a dip in an oil bath. Be warned, if you do this excessively using ATF instead of the Shimano oil you can wash all the Shimano grease out DAHIKT. Lubricated with a generous oil dip these hubs will spill oil over the floor, from both sides not just the disc side (been there, done that!). They are the ones that default change to bottom gear (tension off the cable).

The Alfine 7000 hub, like the 700 hub which is the 11 speed, is oil lubricated and (I presume) has adequate sealing. It default changes to top gear. I would have thought that this is the hub used in Di2 versions (although don't quote me on that)

[LittleWheelsandBig]

This bike is less that two years old, I expect it is the current hub.

I thought the only significant difference between the Di2 and the cable version was no return spring for Di2.