IGH lubrication; a smoking gun.

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StephenW
Posts: 158
Joined: 22 Sep 2010, 11:33am

Re: IGH lubrication; a smoking gun.

Post by StephenW »

I had a notion that I had read something in a Sutherland's manual on Sheldon Brown's site about oil and grease for some three-speed coaster brake hubs, and just oil for others. I went back and had another look, and you are right, it is grease for the brake and oil for the gears. But single speed coaster brakes with oil lubrication are a thing, yes?

I've had another idea. Perhaps every so often I could over-fill the hub with oil, give it a spin, then leave the bike lying on its left side overnight? That way the oil would drain out through the brake, hopefully cleaning it. The rest of the time I would just top up the oil with a small amount. What do you think?
Brucey
Posts: 44517
Joined: 4 Jan 2012, 6:25pm

Re: IGH lubrication; a smoking gun.

Post by Brucey »

that might work, but then again whatever oil remains in the hub may backflush into the gears, and it still leaves you with the possibility of the brake running dry with oil fitted.

In use, oil tends to centrifuge outwards in the hubshell, and then either 'climb' back up the gear trains into the rest of the workings, or drain down into them when the bike is stopped.

I think they stopped using oil in coaster/IGH units because when the brake is used, the oil migrates from the small diameter brake, either out of the hub altogether or into the main part of the hub. If the hubshell is roughly parallel-sided internally (as in singlespeed coaster hubs), you can see that oil will easily run back into the brake in use later on. In hubs like the N8 (where the brake is much smaller than the rest of the hub), the oil may only get back into the brake if the bike is left on its side.

I think that if the brake is used much the heated grease can soften and migrate too, but it'll happen at a higher temperature, e.g. if the correct 'non melting' grease is used.

In any coaster hub it is an imperfect system because (past the brake grease not mixing with the rest) there is rarely anything much to prevent the brake debris from getting into the workings. Even if the wear debris is flushed on the LH side, it can only escape via the LH hub bearing, which is hardly ideal.

That (plus the inevitable drag spring) means that coaster brakes are not top of the performance list.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
StephenW
Posts: 158
Joined: 22 Sep 2010, 11:33am

Re: IGH lubrication; a smoking gun.

Post by StephenW »

Thanks! This is interesting and very useful.

I've had another think, and I've realised that since getting the front drum brake, I am not using the coaster brake so much. (Although it is still very handy when I do want it). Therefore perhaps I am not generating such a large amount of wear debris that it needs to be regularly removed from the brake. I think I will use heat-resistant grease in the brake, and either oil or semi-fluid grease in the gears. I'm not sure which of these would be better. Since oil leaks out faster, perhaps it would be better for carrying away any stray debris from the brake? Do you think there is any difference between the two in terms of how readily they would mix with the brake grease and bring debris from it into the hub? I guess that one advantage of the tapered shape of the hub and centrifuge effect you described is that the oil should tend not to want to go into the brake.
Brucey
Posts: 44517
Joined: 4 Jan 2012, 6:25pm

Re: IGH lubrication; a smoking gun.

Post by Brucey »

on a Nexus 8 I'd use

a) the recommended grease in the coaster brake and
b) a SFG in the main part of the hub and
c) I wouldn't use oil in it.

I say c) firstly because oil is more likely to get into the brake and carry debris into the gears/allow the brake to run dry sooner as previously described. Second, Nexus 8 hubs are usually not sealed well enough to retain oil very well. Most of what you put in will usually come out of the RHS pretty quickly. By contrast the leakage rates with (lots of) SFG inside are much more acceptable.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
StephenW
Posts: 158
Joined: 22 Sep 2010, 11:33am

Re: IGH lubrication; a smoking gun.

Post by StephenW »

Hello Brucey

I finally got round to doing this a month or so ago. I cleaned the innards with white spirit, and removed a satisfying amount of debris. I then added Land Rover SF grease to the main part of the hub and heat resistant grease to the coaster brake (I didn't use the recommended Shimano stuff because I thought it was a bit overpriced).

Since putting it back together, a noise has appeared in gear 5. A sort of whooshing-whirring noise, that only happens when pedaling. Gear 6 is nice and quiet. I checked the cones afterwards, and I think the adjustment is OK, although I may check this again. The hub doesn't skip or do anything else bad. I don't think the chain can be making the noise, since gear 6 is quiet. (Quieter than before I did the service).

Do you think I should be worried? I did drop the innards a couple of times when cleaning them :shock:
Brucey
Posts: 44517
Joined: 4 Jan 2012, 6:25pm

Re: IGH lubrication; a smoking gun.

Post by Brucey »

Hmm, that is a bit weird. Does the noise vary with pedalling load? If not I'd be suspicious that it is part of the clutch and drive mechanism that operates in gears 2,3,4,6,7,8. If so, it is possible that it will make a similar noise in gear 1 too.

Which model hub do you have, exactly?

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
StephenW
Posts: 158
Joined: 22 Sep 2010, 11:33am

Re: IGH lubrication; a smoking gun.

Post by StephenW »

The noise varies with pedalling load.

The hub is SG-C6000-8C.
Brucey
Posts: 44517
Joined: 4 Jan 2012, 6:25pm

Re: IGH lubrication; a smoking gun.

Post by Brucey »

I am slightly baffled by this; it isn't a problem I have previously encountered. Does it make the same noise in gear 1?

If you dropped the internal whilst cleaning it, it is possible that there is damage (eg to one of the roller clutches) or that part of the mechanism is not assembled correctly.

BTW one of my worries about using white spirit to clean the innards is that it is difficult to remove it all once you have finished cleaning. Similarly the SFG may not find its way to all the gears and bearings immediately, either; it is a long way to the RH hub bearing, for example.

If it were my hub I would remove the internal and inspect it carefully. However if you are not so familiar with how these hubs work, there may be a fault that could be missed for a second time.

If the SFG doesn't seem super-mobile in the hub, I'd suggest adding some gear oil to help it along.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
StephenW
Posts: 158
Joined: 22 Sep 2010, 11:33am

Re: IGH lubrication; a smoking gun.

Post by StephenW »

Mystery solved! As you said might happen, I didn't manage to get all the white spirit out of the hub. It had collected in a puddle at the bottom and had washed the grease off the drag spring, making it noisy. (I suppose it must have been making the same noise in gear 1, but I didn't notice because that gear is a bit noisy anyway).

I wiped out the white spirit and added a dollop of grease, and it is running nice and quietly now.

For future reference, what would you recommend for cleaning out the hub? Methylated spirits? Diesel?

Thanks for all your wise advice Master Oogway, I mean Brucey :)
Brucey
Posts: 44517
Joined: 4 Jan 2012, 6:25pm

Re: IGH lubrication; a smoking gun.

Post by Brucey »

glad you got it sorted out.

If you are not sure that the lube has penetrated every part, I'd suggest adding a fair amount of gear oil to the hub, even if it starts coming out a bit.

FWIW if you want to clean an IGH internal I think there are two good ways of doing it

1) strip it down and clean the parts individually. There is much less chance of leaving solvent trapped inside small parts, especially if you blow them off using compressed air. Relube every part carefully as you reassemble it... or

2) fill the hub with an excess of an oil that has a strong cleaning action, and use it for a few weeks. Drain the oil off as best you can, then relube with the chosen lubricant.

If a hub has had a blow-up, you really need to inspect every part, and you can't do that unless the parts are clean, so it is option 1 only. For routine cleaning, option 2 is easiest and best IMHO.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
alexnharvey
Posts: 1923
Joined: 10 Jan 2014, 8:39am

Re: IGH lubrication; a smoking gun.

Post by alexnharvey »

Brucey, re point 2, a motor oil with its detergent content?
Brucey
Posts: 44517
Joined: 4 Jan 2012, 6:25pm

Re: IGH lubrication; a smoking gun.

Post by Brucey »

yes, or ATF works pretty well

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
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tykeboy2003
Posts: 1277
Joined: 19 Jul 2010, 2:51pm
Location: Swadlincote, South Derbyshire

Re: IGH lubrication; a smoking gun.

Post by tykeboy2003 »

Brucey wrote:even if you pay someone in a bike shop to do it once every few weeks when they pump your tyres up and oil your chain.


Do people really do that? It's like somebody with a car that takes it to a garage to have the tyres pumped up and the oil checked. Surely nobody does that do they?

I should have been working in bike shop these last 20 years......
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Mick F
Spambuster
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Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: IGH lubrication; a smoking gun.

Post by Mick F »

Brucey wrote:........... I suspect that the kind of grease that is specified for use in land rover front swivels will be better yet; this (I think) has more anti-corrosion additives and a better EP performance.
This stuff?
http://www.ebay.co.uk/itm/LAND-ROVER-DE ... 1180197793
Mick F. Cornwall
Brucey
Posts: 44517
Joined: 4 Jan 2012, 6:25pm

Re: IGH lubrication; a smoking gun.

Post by Brucey »

yes that is the stuff but you don't have to buy two sachets at once; it comes in bottles instead if you like, The Britpart equivalent STC3435 part is available for about three or four quid a go. Add gear oil to it if you need a thinner consistency (which you probably will do if it is going into a hub with slightly dried out grease in it).

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