Alfie 8 speed problem

d8veh · Post by **d8veh** » 2 Aug 2018, 3:15pm

I dismantled my Alfine hub to regrease it. When I put it all back together everything works OK except that the gear sequence has changed. Instead of 1,2,3,4,5,6,7,8, it's something like 2,3,4,1,7,8,5 but difficult to tell the exact sequence because of the large jumps.

I guess I did something wrong. How do I fix it?

Brucey · Post by **Brucey** » 2 Aug 2018, 4:07pm

there is a clutch that normally operates on the 4-5 shift, to shift between low and high range gears. If this is no longer working at all, you would get a shift sequence of 12341234.

If you dismantle the RH side of the hub, you can easily disable the mechanism for the low/high speed clutch. That would be the first place I'd look. Reassembly of the axle on the RHS is easy to do badly BTW; I do not advise that it is taken apart unless it is absolutely necessary.

cheers

d8veh · Post by **d8veh** » 2 Aug 2018, 7:24pm

I didn't dismantle anything inside. I simply removed the core, wiped it down to clean it, regreased it and reassembled, though I did turn the axle while it was out to spread the grease around.

Brucey · Post by **Brucey** » 2 Aug 2018, 7:41pm

some daft questions;

- what grease did you use?
- is the gear adjustment correct?
- does the gearchange feel normal ?

cheers

d8veh · Post by **d8veh** » 3 Aug 2018, 12:18am

I used Shimano white grease, like what was already in it.
The shifting is normal with 8 stops. All the alignment marks are correct. Basically, everything is correct and normal, except the ratios are mixed up or not in the correct sequence as explained in post #1.

It must be something to do with the internal clutches, bit I don't know how they work.

Brucey · Post by **Brucey** » 3 Aug 2018, 9:51am

what happens is that the original grease gets displaced from where it is needed and it also 'dries out' in various ways. These ways include 'separation' (in which the oil leaches out leaving the thickener behind) and other mechanisms including polymerisation (which is a bit like how vegetable oils can turn into varnish).

Anyhow, just adding more (thick, sticky) grease to a hub (even if it was working OK before) is not the right way of dealing with it. Probably you had clods of dried grease inside the hub before, in places where they didn't cause any trouble. If you add fresh grease, any that contacts the dried stuff immediately lets some of the oil permeate from the fresh grease to the dried grease. The result is that all the grease may now be too thick and sticky to let the hub work OK.

Shimano's recommended procedure is to re-invigorate the dried grease with an oil dip. It isn't a perfect procedure because it doesn't get the dried grease to move where it needs to go. At best there is some oil, for a while, in the places where the grease was displaced from originally.

Other options include using a SFG (semi-fluid grease) or just adding oil to the hub. Hubs of this type run happily in gear oil; the main reason it isn't used is it tends to leak out (oil-lubricated A11 hubs have much fancier seals). However if you add oil and use the hub, it tends to mix with any grease that might be inside and generate a kind of SFG. Surplus oil will leak out and make a bit of a mess. You can then add SFG (say in six months time) to keep the hub working OK.

BTW the power of dried grease to suck the life out of fresh stuff is not to be underestimated; if you just add SFG to a hub with dried grease in it, even that can turn to a thick sticky mess that impedes the hub action, hence my suggestion of adding gear oil and running the hub for a while like that.

Another option is to clean all the lube from the assembly using solvent. This has the advantage that wear debris ought to be removed from the hub. However then getting the fresh lube where it needs to go is not easy; basically you have to lubricate the hub with oil after, unless you want to take the internal apart and grease the parts individually.

Anyway my suggestion is that you scrape any excess grease from the internal and add about 30-50cc of gear oil, and run it like that for a while. It might be that there is actually some damage to the internal, but if it is just thick grease gumming up the works it ought to recover after a little use.

cheers

Cyril Haearn · Post by **Cyril Haearn** » 3 Aug 2018, 10:17am

Could one heat the hub gently to get the grease to flow and distribute, or would this change the grease?

Brucey · Post by **Brucey** » 3 Aug 2018, 11:17am

if it did melt, as soon as it gets cold it would set again, I think.

cheers

d8veh · Post by **d8veh** » 3 Aug 2018, 9:20pm

There was no sign of any dried, thick or compromised grease inside. I don't believe that the problem is anything to do with grease or lubrication.

I've been doing some research on how the thing works. After gear 4, a mechanism shifts to double the 1 to 4 ratios. Without it, the gear sequence would be 1,2,3,4,1,2,3,4. I have all ratios, but in the wrong sequence, so somehow, the 1 to 4 gears are out of sequence. It goes 2,3,4,1,2,3,4,1 with the latter 4 doubled to 6,7,8,5. That means that the mechanism that doubles the ratios is working on the 5th click like it should, but the first click should be on gear 1, though is actually on gear 2.

I'm pretty sure that it was on the 4th click that the adjustment marks lined up. I only made a very minor adjustment to get them exact.

I can't be sure that the gears were in the correct sequence before I started because I didn't check. I'm kicking myself now.

Cyril Haearn · Post by **Cyril Haearn** » 3 Aug 2018, 9:33pm

Could be a good way to learn, making ones own mistakes
You could try searching these fora, the problem has probably been discussed before

Suffolker · Post by **Suffolker** » 4 Aug 2018, 6:37am

"Getting it right" with IGHs of all sorts is something I'm very interested in.

I don't recall seeing any reference to which gear Alfine or Nexus 8 (and 7) hubs should be set in before the cassette is removed, the wheel taken off and stripping/dismantling commences.

Does it matter if it's in 1st, 4th or another when the wheel is removed, and the hub stripped down to remove the innards?

I guess it's important to know which gear it's in, (or was, assuming nothing has been moved around when it was dismantled and relubed) once the whole lot is reassembled, the wheel back in and the job of adjusting the thing to the yellow marks lineup in 4th begins.

Presumably this is also pertinent if one buys a complete new replacement "works" i. e. what gear is it in when received from the supplier?

d8veh · Post by **d8veh** » 4 Aug 2018, 9:28am

Suffolker wrote:"
I don't recall seeing any reference to which gear Alfine or Nexus 8 (and 7) hubs should be set in before the cassette is removed, the wheel taken off and stripping/dismantling commences.

Does it matter if it's in 1st, 4th or another when the wheel is removed, and the hub stripped down to remove the innards?

i don't think it matters which gear you're in because: (a) the shift mechanism is still fixed to the core; (b) you have to operate the shift mechanism to get the cable off and on.

Suffolker · Post by **Suffolker** » 4 Aug 2018, 10:02am

d8veh wrote:
Suffolker wrote:"
I don't recall seeing any reference to which gear Alfine or Nexus 8 (and 7) hubs should be set in before the cassette is removed, the wheel taken off and stripping/dismantling commences.

Does it matter if it's in 1st, 4th or another when the wheel is removed, and the hub stripped down to remove the innards?

i don't think it matters which gear you're in because: (a) the shift mechanism is still fixed to the core; (b) you have to operate the shift mechanism to get the cable off and on.

Thanks. That seems entirely logical.

I have an A-8 in a wheel which I acquired cheaply to investigate (aka "practise on") before starting on my other hubs. It's been disassembled, had the oil-SFG treatment and put back together, but I can't easily check it for shifting unless I take out a "working" wheel and hub from my daily cycle and install it temporarily in its place (a winter job, I think). In light of this topic, I suddenly wondered whether there was something else I might need to take account of.

Brucey · Post by **Brucey** » 4 Aug 2018, 10:58am

in the OP's case, it is most likely that it is something that has happened during the removal/installation process, since it was (I suppose) working before.

However I can't think of anything you can easily do that will upset the synchronisation of the sliding clutch (which moves 4-5 and (as I mentioned upthread) would give you 12341234 shift sequence) with the pawl lifts (which give you all the other shifts).

However aligning the marks on the CJ in the wrong gear does some weird things because the cable pulls are not quite equal. You have to be 100% sure that you are aligning the marks in the correct gear.

BTW I have seen a few hubs where the clutches were not perfectly synchronised, but this usually results in slippage in gear 5 before it all goes to pot.

With these hubs you can easily do ' a sanity check' which is to check that the correct gear ratios are being selected, with the wheel out of the frame. You can do this by counting input turns (on the sprocket) vs output turns (on the wheel) and comparing with the published ratios. However the proof of the pudding is in the eating; you can only check for absence of slippage by riding the bike.

cheers

d8veh · Post by **d8veh** » 4 Aug 2018, 9:13pm

The interesting thing is that all the gears work with no slippage. I will take your advice and count the turns, so that i know whether I have 6 or 8 gears. It's difficult to tell without counting because the jumps around 5th and 8th are so big.

I've been doing a bit more research. There are two things that move when you shift the gears. There are the pawls (3 sets) and a sideways moving clutch that operates in gears 1 and 5, which coincidentally are the two that are messed up, so I guess that's where I need to look for a solution.

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