How to Convert a Shimano Alfine 8 Speed Internal Gear Hub to Oil Bath

Posted on Sep 3, 2012
46

Posted on Sep 3, 2012
46
Reading time: 6 min
Here I explain with pictures the step-by-step procedure for converting the Shimano Alfine 8-speed hub to an oil bath, using ATF fluid. This is a useful procedure if your hub is showing some resistance. Or, if you need to clean the insides after water has entered the hub. The procedure is relatively straight forward, and if you use widely available ATF fluid, it can be very cheap too.

Last updated Oct 14, 2018

Introduction

Just over a year ago, I acquired a bicycle – a Surly Karate Monkey (http://www.14degrees.org/en/?p=1547). Stock standard, the bike is a single-speed. In other words, it has only one gear. This is not conducive to the most efficient cycle touring in the world, so I splashed out and changed to a Shimano Alfine 8-speed internal gear hub (IGH).

Shimano Alfine 8 Speed Internal Gear Hub (IGH)

As you can see, there one cog on the outside, and all the gears, in the form of, literally, gears, are on the inside of the hub shell. The beauty of this setup is that a bicycle with an IGH essentially becomes maintenance free (when one compares with a typical derailleur setup, where you have to clean multiple oily cogs quite often).

IGH’s do need maintenance every now and then, though. I’ve heard of some going for three years before being opened up, and the insides looking like new, but after one year, mine was starting to act up a little; a little more friction than usual, and it was sometimes taking a full half-rotation of the pedals in order for the drive to engage after free-wheeling. I live in Sapporo, Japan, and even though this is the land of Shimano, IGH-equipped bikes are extremely rare here, so there was little to no chance of having the hub serviced locally. Therefore, I decided it was time to pull the thing to bits and have a gander.

The most useful resource for learning about how to pull a Shimano Alfine 8-speed hub to bits was this video below.

Other resources included Nick Foster’s very recent post, of course Muddymole’s postIan’s page about the Nexus hub and adding an oil port (similar to the Alfine, but with less sealing), Lachlan Hurst’s post, wisdomfrom Ecovelo, bike mechanic Sam Larson, Thad at the Golden Wrench and his experiences, Aaron’s Bicycle Repair’s great resource, Sheldon Brown’s advice on lubrication for IGH’s, and last but not least, Hubstripping.com’s page on the Alfine 8-speed hub.

How to Do an Oil Bath on a Shimano Alfine 8-Speed Hub

Step 1

Armed with the right knowledge, and some new tools (I needed a 15mm cone spanner and a centerlock sprocket sans-pin) I got to work.

Tools required for overhauling a Shimano Alfine 8 speed internal gear hub

Step 2

First off is the Shimano Centerlock disk brake rotor. For this, you need a centerlock/cassette tool without the quick-release pin (so it will go over the solid axle of the Alfine hub). The item number on my Shimano tool was TL-FW30.

Shimano Centerlock removal tool (TL-FW30) for a Shimano Alfine 8 Speed Internal Gear Hub (IGH)

Step 3

Once that was off, I was able to access the locknut and cone. Using a 15mm cone spanner and adjustable spanner, I removed the cone.

Removing non-drive side bearing cone of Shimano Alfine 8 Speed Internal Gear Hub (IGH)

Step 4

With these removed, the wheel is flipped over and the drive side bits and bobs removed. This includes the shifting accessories which allow access to a small snap-on plastic cover, which is concealing the snap-ring that holds the cog on. This plastic cover can be pried off by hand very easily.

Removing cover over snapring for cog removal on a Shimano Alfine 8 Speed Internal Gear Hub (IGH)

Step 5

Next is the snap-ring. A small flat-head screw driver does this job well. Keep your free hand over the snap-ring – when it finally comes loose, it will spring off forcefully.

Cog snap-ring removal on a Shimano Alfine 8 Speed Internal Gear Hub (IGH)

Step 6

Once you have the snap-ring and cog off, a metal dustguard and plastic ring needs to be removed. The plastic ring provides access to the knobby ‘grip’ of the main screw-on dust-cap, which holds the guts of the hub in.

Dust cover removal on a Shimano Alfine 8 Speed Internal Gear Hub (IGH)

Step 7

Some people have reported being able to screw open the dustcap by hand (it screws open clockwise, which is opposite to normal), but I had to take to it with a screwdriver to loosen it a little. Once the dustcap comes free, the whole hub shell will fall away from the insides.

On my hub, I noticed right away that water had entered the hub at some stage. I do vaguely remember the non-drive side cone being loose at one stage, and suspect that this was the culprit. If the cone is on properly, then the rubber seal should prevent any water from getting in. The rusty residue was not too bad though, and wiped off easily. After cleaning the hub shell, however, there were some visible blemishes on the bearing race, but no noticeable pitting.

To remove the drive-side bearing cage, the hub needs to be split into two pieces. This is achieved by removing the snap-ring at the non-drive side of the unit.

Shimano Alfine 8 Speed Internal Gear Hub (IGH) insides after 1 year commuting (shows minor water damage)
Shimano Alfine 8 Speed Internal Gear Hub (IGH) insides after 1 year commuting (shows minor water damage)

Step 8

The whole axle unit slides out of the main ring gear unit in two bits (explosion drawing here). There was no visible rust residue inside, so that was reassuring. I cleaned up the drive-side bearing cage, re-greased it, and put the two pieces back together. This is done by lining up the tab on the ring gear unit, and the groove in the axle unit. Even when the tab and groove are lined up, however, the gears need to be rotated around a little to get the ring gear unit to mate to the axle unit (this can take a while to get right).

Everything back together, with snap-ring re-installed, the whole lot gets dunked in auto transmission fluid. Mine was just normal, service station (gas station) ATF, using a 2 litre PET bottle as a dunking container.

Shimano Alfine 8 Speed Internal Gear Hub (IGH) soaking in oil bath (auto transmission fluid - ATF)

Step 9

I left it in for about 5 minutes, and then let it drain for about 10 minutes while I was re-greasing the insides of the hub casing.

It is really important at this point to allow the hub to drain well. If too much ATF is left on the hub, it will leak out of the disk-brake (non-drive) side of the hub. If you have a disk brake installed, this will cause ATF to leak onto the disk, ruining your day.

Shimano Alfine 8 Speed Internal Gear Hub (IGH) draining after oil bath (auto transmission fluid - ATF)

Finishing Up

The innards then went back into the hub shell, the various dust covers put back on, the cog and snap-ring (which can be infuriating to get on) and the gear-shifting accessories. And then I took it all to bits again. No joke. I had put the drive-side bearing cage on the wrong way around. The picture above shows it in the correct orientation. That was not a happy moment when I had realised I had put it on wrong…

In all, it took me about 45 minutes plus another 20 minutes to rectify the bearing cage issue. Next time it will take around 30 minutes, I would say. That’ll probably be in another 12-18 months time.

Without the oil bath, the hub just has grease inside it. This means there is quite a lot of friction. For example, when back-pedaling the bike  on a workstand, the back wheel will start to rotate backwards. With the oil bath, however, backpedaling does not affect the back wheel. I didn’t notice any difference in gear changing; that is as smooth as ever.

Comments | Queries | Discussion

46 thoughts on “How to Convert a Shimano Alfine 8 Speed Internal Gear Hub to Oil Bath”

  1. Dominic Earley

    I have an Alfine 8, on my belt drive, Scott Sub 10. I love everything about it. It is working perfectly but I figure I had better bite the bullet and open it up soon, as I just ticked over 5,000km, after owning it for 16 months.
    I live on the Sunshine Coast in Qld Australia, and although there are many bike shops, none of them want to touch it.
    I have cleaned an old tin and I have some ATF, left over from a car service. I will be going for it soon. Thanks for all your advice fellas.

    1. Glad to hear this post has helped (and sorry for the late reply). Did you end up having a look inside the hub?

  2. Hi,
    I’ve a Shimano Nexus 8 hub. I had previously taken it to LBS. I think the mechanic was not interested in taking hub apart. When I striped the hub today I was shocked at the amount of crud everywhere. The cage bearing was very loose, the ball bearings just fell out of it. I’ve ordered a new one £2.50. What’s the best method to clean all the crud off? Excellent article thank you.

    1. @Kenny – I have seen somewhere someone using a hot oil bath, and I would say that that would be the ‘best’ way to get the internals completely clean and stripped of grease and crud. I guess it depends how deep into the internals the dirty grease has gone. If you can see crud all the way into the inside of the internals, you might need to really get drastic. Like hot oil bath drastic. I don’t have a hot oil bath, so I would possibly try soaking the internals in a bucket of petrol and rotate the hub/axle to work the crud out. Then spray the whole thing with parts cleaner to get rid of the petrol residue, and then do the transmission oil dunk. It would be a fairly big job with lots of mess, but possibly better than getting a new hub!

  3. Thanks if your work above, I am going to service my Alfine 8 speed hub tomorrow. Your instructions have given me the confidence to take my hub to bits.

    Nice one.

  4. Pingback: Inspecting my Shimano Alfine 8 IGH… « The Lazy Rando Blog…

  5. Hi,

    I just serviced my Alfine 8 this weekend using the oil bath.
    Compared to the grease lubrication pedalling seems to be a bit smoother but now I can ‘feel’ the gears when applying power. Do you also notice this?

    Regards,

    Sjors

    1. Hi Sjors, I had heard that switching to an oil bath does, naturally, reduce the “vibration dampening” that the grease provides. And yes, I can now “feel” the gears more. Have you ever ridden a Rolhoff hub? That’s one example of a hub where you can really feel the internal gears!

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

See More Like this