Shimano Alfine 11 - Longer term reliability

[jb]

Part 1
To strip down the Alfine 11 IHG in order to check out the gear selector mechanism is working properly
To be read in conjunction with the parts list .

Shimano parts list (see Shimano web site for a full PDF file with part Numbers & descriptions on)

1. Remove wheel from bike
2. With all wheel nuts, non-turn washers and disc (if fitted) removed - clamp in vice by the flats on the axle on the opposite side to the sprocket.
3. Remove the cassette joint assembly – check it for free movement and clear out the cable groove.
4. Remove the sprocket circlip cover (item 41), circlip (item 39)(removed with two small electricians screwdrivers, sliding them down the sprocket drive grooves & flipping the circlip out), the sprocket & the thin steel dust cover(item 28).
5. Now the large plastic end cap needs to be loosened (Item 26). This is done with the special tool (item 50) which has shallow lugs that engage with recesses in the plastic cap. Without engaging all lugs at once it is hard to get enough drive torque without damage to the cap. I thought about making a ring from plywood and screwing some steel plates on as a quick home-made tool but in the end I got one wire cut at a local firm (I will add a dimensioned drawing when I find it). The important thing is not to damage the face that presses onto the aluminium hub as this will cause it to leak. IT UNSCREWS CLOCKWISE. Leave it on but loose
6. Now turn the wheel over & clamp on the opposite side, with the cone spanners hold the lower cone and undo the lock nut (item 25) - remove this. Unscrew the cone (item 34) which will initially be stiff as it has an ‘o’ring seal under it (item 2), it will come off with a tin pressed dust cover attached.

Remove lock nut and bearing cone

7. A clean drip tray needs to be at the ready.
Hold the top axle, undo the vice, lift out the wheel, invert it & with it over the tray unscrew the plastic cap (don’t damage the large sprocket oil seal) & remove it, the whole internals can now be lifted out (turning anti-clockwise to free of the roller clutches). Place quickly onto the tray to drain awhile, also tip any oil out the hub body onto the tray.

Internals removed from hub & left to drain

8. Inspect the oil for ‘glitter’ using a torch & also inside the hub. The oil may be dark but should not be in the least bit sludgy if the oil has been changed at the recommended intervals. The ball race cannot be removed without removing and possibly damaging the seal. If the cone looks fine the balls and outer race will probably be ok too.
9. When most of the oil has drained off replace in the vice & clamp on the sprocket side axle.
10. Everything that needs to come off is now held in place with the circlip (item 3) that can be seen on top of the whole stack. Remove this with a screwdriver (don’t damage the ‘o’ring (item 2) on the axle nearby)

circlip shown that hold the whole caboodle together, also the end plate with the two anti-spin springs showing through the hole

11. Remove the carrier hold plate (item 4) this takes any side thrust generated by the torque but also holds two anti- spin springs (Items 5 & 6). Check the springs are okay & free to slide around in their respective grooves (they should slide in one direction more easily than the other) if they have thinned at any point best to replace them. LEAVE THEM IN PLACE AS THEY STOP THE SUN GEAR FROM COMING OUT AND MESSING UP THE GEAR TIMING.

12. The first basket of gears can now be pulled off the axle (item 7 & 8 should be held together BY THE SPRINGS 5 & 6), twist anti clockwise so as to flatten the pawl and allow the assembly to slide over it. Spin the sun gear & check all the planets and ring gear rotate freely. DO NOT DIS-ASSEMBLE THIS ITEM ANY FURTHER unless you really want to - getting the small planet gears timed up correctly is a right faff.

final drive gears. sun gear held in place by the anti- spin spring shown

[jb]

Part 2

13. The tabbed guide ring (item 9) can now be weedled out, it has to be turned as well to allow the tab to follow the grooves so it can come off.
NOTE: easily left off when rebuilding.

Tabbed guide ring item 9 (marked three!) needs to be pulled forwards turned for tab to line with groove and then removed

14. Gear carrier 2 (item 10) can now be slid off turning as before to flatten the pawls, also as before the sun gear should remain in the cluster to prevent the planet gears losing their timing. It cannot escape without removing the small planet gears.
Note the lugs that engage the carrier unit 1 (item 12) make sure they go back the same way (the shiny marks will give a clue). Check for damage & free movement.
15. Slide off the last sun gear (item 11) turning it anti-clockwise to flatten the pawls. Note which way round it goes. (gear teeth out plain side in)

last removable sun gear, press down pawls to allow it to slide over. Small hair springs that operate the pawls just visible in their grooves

16. Slide off the remaining gear cluster (item 12) and the ball bearing cage (item 13) also note the roller clutches on items 12 & 17 which engage with their respective gear carrier cages 7 & 12. These have to be turned against each other on assembly to help them go in.

strip down complete for most purposes, pawl hair spring ends visible, also the fixed sun gear and behind that the gear clutch & roller clutch on the sprocket unit.

We have now gone as far as is practical, the only reason for going further would be if the sprocket side wheel bearing had gone (item 18 & 20) or one of the oil seals (item 19 & 23 or the splined washer 21) is leaking – unlikely the bearing will have gone since it runs in oil and I don’t know what the spares situation is with it, the seals are obtainable. You will also need special tool (item 47), I made one on my lathe; it needs to be a fairly good fit.

Next is to examine the axle assembly and check it is all ok.
1. There are three selector pawls, check that they spring in and out easily, check that none of the fine springs are broken. (no item numbers; these all come as part of the axle assembly)
2. Check that the pawl faces are not chipped or worn and that their mating ratchets inside the floating sun gears are not worn. (they are not razor sharp when new)
3. To check all is operating correctly it is easiest to re fit the cassette joint and now place the axle back into the upside down bike frame. Connect the gear cable and run through each gear – watch the pawls flick out and retract.

4. For correct operation they should follow the following sequence –
11th pawl 1 (furthest from fixed sun gear) out, pawl 2 out, pawl 3 in
10th pawl 1 out, pawl 2 in, pawl 3 out
9th pawl 1 in, pawl 2 out, pawl 3 in
8th pawl 1 in, pawl 2 in, pawl 3 out
7th pawl 1 out pawl 2 in, pawl 3 in
6th clutch disengages, pawl 1 out, pawl 2 out, pawl 3 in
5th pawl 1 out, pawl 2 in, pawl 3 out
4th pawl 1 in, pawl 2 out, pawl 3 in
3rd pawl 1 in, pawl 2 in, pawl 3 out
2nd pawl 1 out, pawl 2 in, pawl 3 in
1st pawl 1 in, pawl 2 in, pawl 3 in

5. As the cable pulley is turned by hand the selector should turn smoothly against the spring, if it doesn’t turn easily and /or the pulley will turn but the selectors don’t there may be some grit or piece from a damaged part that is snagging it, try flushing the whole mechanism with plus gas or similar.

The most likely cause of wrong gears being selected is broken pawl springs or stuck pawls any other damage to the selector will likely cause it to not work at all or jam up.

Check all gear teeth for breakages although being press formed they don’t look as good as machine cut gears.
The gear carriage assemblies can be flushed out but don’t leave fluffy rag bits inside them . There are thin circlip springs holding the planet axles in DO NOT REMOVE THEM.
Check the thrust shim in item 7 that item 10 presses against if it is wearing it could be the cause of the ‘glitter’ in the oil. I had one that wore for no apparent reason – it could have not been properly hardened? Sideways thrust is generated by the helical gears in the first set of gears (item 12)

thrust washer held in item 7 by a fine circlip spring - also keeps the planet gear axle shafts from coming out - so watch it.

The thrust shim shown inside the ring gear item 7. the planet assembly that runs against the shim is shown next to it. The sun gear cannot escape without removing the planet gears.

For any replacement parts go to a Shimano dealer and give them the part number shown next to the item in the chart (on the full chart available on the Shimano web site) you might be surprised at what you can get or you may have to buy a part assembly.
Or alternatively if you can pick up a broken second hand one; it might have spare undamaged springs in it.

Assembly of the inner unit is a reversal of above – don’t forget to fit the ball cage first (item 13), squirt some oil round the planet gears as it might take a while for oil to reach inside to their needle rollers.
Rotate the sun gears whilst sliding onto the axle in order to push the pawls down, likewise the roller clutches and to mesh the gears as they mate up.
Fit item 9 before sliding on the last ring gear assembly (item 7).
Finally the two anti-spin springs need to have their bent ends engage the hole in the back plate before the circlip is clipped in place – Note there seem to be two different designs, one has two holes opposite the other just one.
If it is desired to fit a new oil seal in the hub at this time, push the old one out, there is a tool for fitting these in but it can easily be pushed in place with a thumb (and cause less damage) it clips into a shallow groove.

1. Now secure the unit by the axle in the vice, sprocket side down, lower the wheel and hub carefully into it twisting it as the roller clutches come into contact. Be careful not to damage the oil seal in the hub by rubbing the axle screw thread on it.
2. Squirt some oil onto the cone ‘o’ ring, run the cone down the axle until it stops against the bearings, slacken a tad and spin the wheel to bed it down and make sure nothing is scraping.
3. Fit the lock nut and run it up to the cone
4. Lightly turn the cone until pressure is felt, back off half a turn & nip up the lock nut
5. Place finger and thumb over the lock nut so that they are touching the hub, move the wheel rim up and down and feel for a slight bit of play through your thumb. If none is detected back of the cone until it is. Then by small increments turn back the cone and nip the lock nut until the play is almost undetectable then tighten the lock nut. Note: an over-tight cone can cause creaking when cycling, excessive play will strain the mechanism.
Take it out the vice and spin the cluster via the sprocket spline, there should be no lumpiness.
6. Re-fit the plastic cover and nip up making sure the mating surfaces are clean
7. Fill with 25ml of oil & leave on its side for a while. Then check for any leaks from the axle or plastic cover before fitting the dust cover & sprocket.

[Brucey]

good work fella!

Your oil looks pretty murky there... how far had that gone?

cheers

[barrym]

Wow! Great post. Don't have one of these hubs currently but it is likely and this will prove extremely valuable. Thank you.

[Blackredgold1964]

Fascinating, thanks, my 11-speed hub is only 2 months old and what you describe is too complicated for me but I'll keep this for future reference anyway.

[jb]

Your oil looks pretty murky there... how far had that gone?

cheers

That was the original Shimano magic oil after a 1000 miles (the pictures are from different times by the way I just picked them to illustrate the point).
It was full of filings (glitter) from the wearing thrust ring.

I think this hub will be far easier to strip down to this stage than the Nexus/Alfine 8 by the way. Everything comes off in modules & holds together. I've taken a Nexus partly in bits and it looked a bit more involved.

[rfryer]

Thanks, JB, that's an excellent resource. I can now look forward to having an excuse to take mine apart!

[bobc]

Thanks JB, top job

[MikeF]

Surely JB's post should be on too good to lose?

[bobc]

Interesting reading and comparing the alfine11 with the sturmey archer 8 speed: the alfine uses the same "sun locking -> gear up" system as the SA8 withthe addition of a "high ratio/low ratio" clutch.
If you analyse the SA8 gearing system it is possible to arrange for even gearing steps and preferential single or dual stage gear-ups with the exception of double jumps between the lowest (000 to 001) and highest (110 - 111) ratios. If we assume shimano have eschewed the 111 ratios because of the inefficiency of 3 gearing stages and tried to miss out the lowest jump in the higher ratio; this opens the question why did they not offer a 13 speed with wider range instead of 11;- any thoughts jb?

[jb]

Well firstly I would suggest they are struggling for space as it is on the selector arms, without making the axel significantly fatter and the hub correspondingly bigger I cannot see how they would get more selections onto it. Rohloff have had to go the way of having two clutches to avoid making the pawl area too busy. Which means for Shimano, a radical design change away from their own pet system which is orientated more towards an effortless change in all peddling conditions using one cable – which Rohloff isn’t.
Secondly as far as I can see the only other possible gear not being used is direct drive. I’m not familiar with the SA system.

[bobc]

I can readily believe that they felt their single cable selection system would start to be flakey with more ratios to select from - plenty folk already have trouble with just(?) 11 speeds (see many of the pages above). But the cogs are already in there to do 13, they've made a choice not to..... (OK the cogs are in there to do 16 but at the price of poor efficiency and/or non-linear jumps in 3 of 'em).
Put simply, there's a clutch & 3 pawls all of which can be in or out - that's 16 combinations!
There's loads of data on the web about the SA 8speed, I'm actually using one so I looked it up, and it is an instructive simple introduction to how the upper and lower halfs of the alfine11 work.
It's worth calculating the 3 stage gear-up ratios and how they are combined to get the 8 speeds - maybe I'll bung it on its own thread

[jb]

Ah, I see what you mean, but 2 of the gears are part of the same shaft so cannot be used independently making a maximum of 12 possible combinations

[jb]

Here are the Alfine 11 gear combinations in diagram form. (photos! unfortunatley can't load pdf)

Alfine 11 gear diagram

Alfine 11 gear combinations

Alfine 11 gear combinations

[bobc]

Gotcha - the 2 suns that share "stepped" planets obviously can't both be locked at the same time, so that waves byebye to 2 more ratios bringing us down to 11
great info jb thanks again.