Alfine 8-speed ?clutch? problem in gears 2, 3, 4

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vandjq
Posts: 86
Joined: 16 May 2007, 11:30am

Re: Alfine 8-speed ?clutch? problem in gears 2, 3, 4

Postby vandjq » 26 Mar 2018, 7:10pm

Rather than start a new thread, I thought I'd add my experience to this one. I have a Cube Travel Pro with a Shimano Nexus SG-6000-8D internal gear hub. I recently had an accident where my Revoshift gear changer was broken. I ordered a new one from SJS Cycles (excellent source of IGH parts) and thought I would take Brucey's advice and replace my cassette joint CJ-8S20 with a CJ-8S40 for greater weather protection. The Revoshift came with a new cable and housing as well. I carefully fitted all the parts using the Shimano cable adjusting tool and lined up the yellow marks on the cassette joint by moving from 1st to 4th gear. But when I moved up to 5th then back to 4th the marks did not line up exactly. Today I cycled 5 miles to work and the hub slipped twice in 4th gear. On neither occasion was the hub under any great load.

I've had the bike for nearly two years now and really like IGH because shifting is so easy and I can drop down the gears instantly if I have to stop quickly. But I have been plagued with this problem of gear slippage. I ride very gently and my commute is only 5 miles each way with no serious hills. I never stand on the pedals and always ease off when changing gear. But still it slips. What to do?
:?
Last edited by vandjq on 3 Apr 2018, 11:40pm, edited 1 time in total.

Brucey
Posts: 34288
Joined: 4 Jan 2012, 6:25pm

Re: Alfine 8-speed ?clutch? problem in gears 2, 3, 4

Postby Brucey » 26 Mar 2018, 10:04pm

vandjq wrote:Rather than start a new thread, I thought I'd add my experience to this one. ...... I carefully fitted all the parts using the Shimano cable adjusting tool and lined up the yellow marks on the cassette joint by moving from 1st to 4th gear. But when I moved up to 5th then back to 4th the marks did not line up exactly. ..... But still it slips. What to do?
:?


This is exactly symptomatic of either

a) the cable not being lubricated
or
b) there being some fault in the hub that means that the cable is not retracted properly.

My money is on a); new cables that come with shifters are typically bone dry and the cable housing won't be lubed either.

There is no way the hub can work properly if the symptoms are as described above.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

vandjq
Posts: 86
Joined: 16 May 2007, 11:30am

Re: Alfine 8-speed ?clutch? problem in gears 2, 3, 4

Postby vandjq » 27 Mar 2018, 12:22pm

Brucey,
Thanks for that. You're right, there is no lubrication on the cable or housing. What's the best way to lubricate a cable without attracting a lot of dirt?
:?

Roadster
Posts: 443
Joined: 26 Jul 2016, 2:12pm
Location: E.Lancs/W.Yorks border

Re: Alfine 8-speed ?clutch? problem in gears 2, 3, 4

Postby Roadster » 27 Mar 2018, 2:05pm

Serious dirt enters only at the hub end of the cable and, if this is a problem, can be prevented with the 840 booted version of the cassette joint. One lube I've seen recommended is chain oil, but I use a calcium grease http://www.morganblue.net/product/calcium-grease-200cc/
for its greater moisture-resistant advantage over lithium greases, although either type is better than nothing.

Brucey
Posts: 34288
Joined: 4 Jan 2012, 6:25pm

Re: Alfine 8-speed ?clutch? problem in gears 2, 3, 4

Postby Brucey » 27 Mar 2018, 5:32pm

vandjq wrote:Brucey,
Thanks for that. You're right, there is no lubrication on the cable or housing. What's the best way to lubricate a cable without attracting a lot of dirt?
:?


there are lots of ways but I use a smear of finish line Teflon grease on the cable and add some oil. The result is less draggy than just grease and less oozy than just oil. If you are worried about water entering then some folk would advocate using a smear of Vaseline at the top end of the cable. Leakage at the bottom end is not such a big problem with a sealed CJ.

BTW I would be cautious of using a grease with a calcium based soap; these often confer waterpoofness by the water reacting with the soap to thicken it, which would presumably cause a cable to turn draggy if water gets in.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

vandjq
Posts: 86
Joined: 16 May 2007, 11:30am

Re: Alfine 8-speed ?clutch? problem in gears 2, 3, 4

Postby vandjq » 27 Mar 2018, 6:53pm

Thanks again Brucey,

I have a can of Granville Marine White Grease 'with zinc oxide anti-corrosion inhibitors in a high quality lithium soap base.' Would that do? And how do you get the oil into the housing? Do you use a syringe?

Brucey
Posts: 34288
Joined: 4 Jan 2012, 6:25pm

Re: Alfine 8-speed ?clutch? problem in gears 2, 3, 4

Postby Brucey » 27 Mar 2018, 7:10pm

not used that grease so it might be good or it might be rubbish inside cables ( I suspect the latter; in cables, most white greases with zinc oxide in turn to gungy powder after a while). I normally make sure the cable is covered in oil as it enters the outer; even though the bottom end of the cable will presumably be a bit dry by the time it is pushed that far, that seems to be enough; the oil works its way downwards in service anyway.

Lubing cables is far from straightforward because not only do you have to get lube in there but

a) it needs to stay in there (so oil alone is only temporary)
b) it needs to have the right viscosity characteristic (most greases are both too thick and very non-linear at low speeds, and any particles or solids in the grease affect this)
c) it needs not to soften the cable liner or make it swell unduly

On the latter point liners and oils vary but most mineral oils seem to cause some softening of most liners rather than none. A fully synthetic oil will either cause no problems at all or will be terrible.

BTW shimano make some special cable grease; I don't use it mainly because it is ridiculously expensive.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

vandjq
Posts: 86
Joined: 16 May 2007, 11:30am

Re: Alfine 8-speed ?clutch? problem in gears 2, 3, 4

Postby vandjq » 27 Mar 2018, 8:09pm

Thanks Brucey,
On the subject of lubricating the cable, on my bike part of the gear cable run is inside the down tube, which is a pain as far as routing the cable goes, but does mean that I can lubricate it again at the point where it leaves the down tube. I don't know why they bothered, as the rear brake cable runs outside the tube.
:)
Last edited by vandjq on 31 Mar 2018, 7:36am, edited 1 time in total.

Roadster
Posts: 443
Joined: 26 Jul 2016, 2:12pm
Location: E.Lancs/W.Yorks border

Re: Alfine 8-speed ?clutch? problem in gears 2, 3, 4

Postby Roadster » 29 Mar 2018, 1:47pm

Brucey wrote:BTW I would be cautious of using a grease with a calcium based soap; these often confer waterpoofness by the water reacting with the soap to thicken it, which would presumably cause a cable to turn draggy if water gets in

This seems a spurious objection to me. I mean, a grease found eminently suitable for use in marine environments is hardly likely to become worse than useless when exposed to the conditions typically found within the gear cable of a bicycle. Even if it did thicken to the extent you presume it would, its coefficient of friction would still remain extremely low.

Speaking from experience, I applied Morgan calcium grease to the inner of my own gear cable when I installed it two years ago. The cable is fully enclosed over its entire length from handlebar grip to rear hub so plenty of opportunity there for it to turn draggy, but it hasn't. On the contrary, it has required no further attention, and if I hold down the downshift lever of my Zerode-modified SRAM X9 shifter, my Alfine 8 rear hub will click down rapidly to 1st gear entirely of its own volition.

I get the distinct impression that you advise caution in the use of calcium grease not because of any real risk of the cable turning draggy, but merely because someone other than yourself suggested it.

Brucey
Posts: 34288
Joined: 4 Jan 2012, 6:25pm

Re: Alfine 8-speed ?clutch? problem in gears 2, 3, 4

Postby Brucey » 29 Mar 2018, 4:02pm

I own and use various calcium based greases for all kinds of things, but cables isn't one of them. When they thicken (not all do) they 'skin up' which doesn't cause enough drag to worry about in (say) an outboard drive, but might easily make a gear cable too draggy; it doesn't take much.

I advise caution in selection of cable lubricants in general. Most greases -regardless of thickener system- are simply not suitable eg for the reasons I described earlier. You will note that I suggested caution regarding calcium greases, because they do vary; folk finding that they can't get 'brand X' in their local shop are wont to buy the closest thing, which often isn't very close at all.

In order to provide a sound recommendation it is useful to know the identity of the cable inner, the housing, the grease ( viscosity grade, oil base stock used etc) and whether the spring tension/cable routing is 'normal' or not if you are using a non-standard shifter. A cable setup that is successful is IME one that will withstand being left out in the weather for a couple of years and being used for several thousand miles in all conditions.

If you have discovered a set-up that works, then great, but that is not to say that another setup might work with the same lubricant, an ostensibly similar lubricant, or under other service conditions.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Roadster
Posts: 443
Joined: 26 Jul 2016, 2:12pm
Location: E.Lancs/W.Yorks border

Re: Alfine 8-speed ?clutch? problem in gears 2, 3, 4

Postby Roadster » 30 Mar 2018, 3:41pm

I didn't suggest using any calcium grease, but only the Morgan which is formulated specifically for use on bicycles.
Let's try to keep some sense of proportion here. With regard to a bicycle which has been left out in the weather for a couple of years and been used for several thousand miles in all conditions, a draggy gear cable is likely to be the least of its problems!

Brucey
Posts: 34288
Joined: 4 Jan 2012, 6:25pm

Re: Alfine 8-speed ?clutch? problem in gears 2, 3, 4

Postby Brucey » 30 Mar 2018, 4:05pm

that is exactly the treatment that many roadster bikes receive and if they are set up right, they need virtually no maintenance in this time/mileage. Having cables that fail in this time is very annoying indeed, and is quite avoidable.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Roadster
Posts: 443
Joined: 26 Jul 2016, 2:12pm
Location: E.Lancs/W.Yorks border

Re: Alfine 8-speed ?clutch? problem in gears 2, 3, 4

Postby Roadster » 1 Apr 2018, 1:35am

Presumptions have no role to play in proper scientific method, which requires actual testing of the specific product before determining its suitability for the job.
Your concerns are unfounded: calcium greases have good compatibility with other types and exceed them in water resistance. The Morgan stuff is eminently suitable for the lubrication of bicycle cables, and especially so for service in extreme conditions.

AndrewJR
Posts: 14
Joined: 26 Nov 2017, 10:58am

Re: Alfine 8-speed ?clutch? problem in gears 2, 3, 4

Postby AndrewJR » 20 May 2018, 5:05pm

Hi, this is the original thread poster, after some absence. I've been waiting (since November) for a time when the weather is good enough to attempt a hub strip myself, but not good enough that I actually wanted to do that, instead of go riding. My garage is too full of bikes so I have to strip this outside. The hub has been behaving (and misbehaving) exactly the same the whole time - no improvement or degradation.

Anyway, I think Brucey was bang on with some of his comments. There are two (roller) clutches that take the drive onto the hubshell (one used in gears 1 and 5, the other used in 2,3,4,6,7,8. My problem symptoms suggest that the problem is with the clutch used in gears 2,3,4,6,7,8. Here is a picture of my big roller clutch. It is missing one roller, right in the middle of the picture.

Missing roller.jpg


It seems fairly pointless trying to find any other problems until I fix this obvious one.

Is there any way I can easily obtain one of these rollers? By digital vernier calipers I measure some of the in-place rollers as 3.46mm diameter (+-0.02ish) and 4.87mm long (+-0.02ish). I don't think Shimano will sell them direct? So perhaps I can find a generic roller-bearing replacement. It seems silly to pay ~£160 for a whole new innards when I probably need just one roller bearing.

Since there has never been any noise from this hub, apart from the first times it slipped, I don't think the roller came off and got minced in the workings. Also, since I have never dissassembled this hub myself before, my guess is that the missing roller is on my local bike shop workshop floor somewhere. I noticed that when I took off the big left-hand-thread cover that the whole wheel drops suddenly off the shaft which is held in the vice, and a roller could easily get dislodged then. Also, getting the assembly back in, that clutch is quite tight on the bearing surface and it would not surprise me if a roller got disclodged during re-assembly, and you'd probably never notice it as it would just pop onto the floor with very little noise. Once you're at that point, you can't see the clutch any more, so there'd be no visual clue at that stage.

Andrew

Brucey
Posts: 34288
Joined: 4 Jan 2012, 6:25pm

Re: Alfine 8-speed ?clutch? problem in gears 2, 3, 4

Postby Brucey » 20 May 2018, 6:21pm

I might have a spare roller of that size in my box of spares. I'll take a look.

I have seen many misassembled IGHs that gave trouble in service, but having bits missing is not that common. Better I suppose that it never made it into the hub than if it was floating around inside and smashing everything to bits...

Not sure if one roller missing would explain all the symptoms you are seeing. It makes sense to

a) check very carefully that the missing roller isn't lurking somewhere
b) check the spring preload on that roller clutch is set correctly
c) check that the part the rollers bear against isn't cracked; the uneven loading arising from one roller being missing may have caused a problem of this kind.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~