IGH lubrication; a smoking gun.

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Mick F
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Re: IGH lubrication; a smoking gun.

Post by Mick F »

Britpart?
http://www.britpart.com/all-parts/stc3435/
Why don't they tell you the price?
Mick F. Cornwall
Brucey
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Re: IGH lubrication; a smoking gun.

Post by Brucey »

Mick F wrote:Britpart?
http://www.britpart.com/all-parts/stc3435/
Why don't they tell you the price?


I was wondering that too; they used to... I suspect it is because they sell to the trade as well as to private individuals, and now price accordingly. Give 'em a call why not?

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Mick F
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Re: IGH lubrication; a smoking gun.

Post by Mick F »

Yeah .......... maybe next week.
Prefer to buy some locally, as I'll be Britpart's postage will cost as much as the grease.
Mick F. Cornwall
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mjr
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Re: IGH lubrication; a smoking gun.

Post by mjr »

Since the last top-up, my Nexus 3 coaster-brake hub has been emitting more semi-fluid grease (Landrover front swivel) than previously through the brake side of the hub. Is this normal in warmer weather, have I simply grossly overfilled it (new syringe at last fill - the markings might not be accurate), has the brake-side ring bearing grease been thinned by the SFG - and if so, should I disassemble and regrease the bearings or not worry about it?

I'm going to start using an X-RD3 soon, for various reasons mentioned in past posts. Any tips on keeping the gear lubricant (SFG again?) out of its brake?

viewtopic.php?p=1115382#p1115382 mentions
Brucey wrote:it is possible to install earlier parts in some cases which improve oil retention. However using a semi-fluid grease is probably the way ahead.

Which parts and is it worth doing for an SFG-lubricated hub?

Sorry again for all the questions and thanks in advance for any answers.
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
All the above is CC-By-SA and no other implied copyright license to Cycle magazine.
Brucey
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Re: IGH lubrication; a smoking gun.

Post by Brucey »

earlier parts can be fitted to the RHS of some sturmey hubs to improve lube retention. I'd suggest that this isn't going to help an SA drum brake hub, it will just help to disguise the usual culprit which is too much lube in the hub.

I have experimented with an upgraded seal on the LHS of an SA brake hub, which allows a generous fill of SFG without brake contamination, but it isn't easy to do this mod and furthermore it isn't really necessary; provided you don't overdo it, SFG tends not to migrate into a drum brake; to do that it needs to beat the centrifugal force somehow, or you need to leave the bike on its side or something.

A coaster brake is a different kettle of fish; there is nothing inside the hub either to stop the lube migrating to the brake, or out of the hub altogether. If you have lube coming out of there, I'd suggest that you wipe away the excess and carry on. If the lube ever stops coming out of the hub, then would be a good time to inspect the internals and see how well they are lubricated. Until that happens the LH ring bearing is almost certainly still being lubricated by the gradual flow of SFG out of the hub.

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Re: IGH lubrication; a smoking gun.

Post by mjr »

Thanks 1000. I don't suppose anyone's ever measured how much lube each hub holds before it spills, have they? It would be nice not to drip any more over the world than needs must.
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
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Suffolker
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Re: IGH lubrication; a smoking gun.

Post by Suffolker »

I'm psyching myself up to deal with my Alfine 8 hub. I've got Silkolene PRO RG2 red grease for the ball races/bearings, and plenty of Land Rover SFG for the rest of it.

Perhaps a dumb question, but when I have the hub innards out, what's the best way of applying the SFG to it? My plan is to fill a hypo with it, and then squirt it liberally over and into the relevant parts i.e. all but the greased races. Is this a good approach, or is there a more precise or preferable way of getting the SFG to the parts it needs to lubricate?
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Re: IGH lubrication; a smoking gun.

Post by Brucey »

the whole point of the SFG is that it can be made to be reasonably mobile inside the hub, and that it contains anti-corrosion additives (amongst other things). In the case of an Alfine hub don't see much point in using a different (thicker) grease in the bearings, because

a) this arrangement won't last and
b) it may impede the SFG from getting to the seal lips and keeping them happy.

Since there is no way of knowing if the resultant mix of greases is any good for anything, I'd counsel against it in this case, without some testing.

If the SFG seems a bit too thick to be mobile inside the hub, it may be a good idea to add some gear oil to the mix. In general it is a good idea to shoot for the most/runniest lube that will stay inside the hub without causing other troubles. In the case of an Alfine hub this is quite a generous amount. Put it this way if you look at the volume of oil inside an Alfine 11, this seems positively miserly by comparison with the amount of SFG that you can get to stay inside the same hub. An Alfine 8 is usually sealed well enough that you can use quite a lot of SFG inside it.

Other IGHs are a different kettle of fish; for example a SRAM 7 hub has pretty much no seals and not much of a lip inside the hubshell either. Only a relatively thick lube will stay inside the hub and even then any excess will come out.

To apply the SFG usefully it is as well to work out which bits are most likely to suffer without it and proceed accordingly, concentrating on

- bearings
- seals
- pinion bearings
- gear engagements

In an Alfine 8 if the SFG is runny enough it will find its way everywhere eventually but if it isn't, or there isn't enough inside an otherwise clean/dry hub, it is better if it is applied directly to these parts. If you remove the LH snap ring from the internal, and remove the gear trains, you can quickly gain access enough to lubricate about 90% of the internal. The remaining parts that are not accessed this way are the shift mechanism and the RH hub bearing (under the sprocket as it were). The RH hub bearing is vulnerable to wear in any event, and if it just has a little sticky grease in it this is far from ideal.

if you don't want to remove any parts from the internal, just add plenty of SFG/ SFG oil mix wherever you can. If you don't want to remove the internal at all, just remove the LH cone and pour the lube in at the LH end. If it is runny enough it will work its way to where it needs to get to.

FWIW if an Alfine 8 with factory lube in it goes bad the water usually gets in at the driver seal and busily wrecks the ring bearing. The next parts to suffer are (surprisingly) the roller bearings in the planet pinions and (less surprisingly) the roller clutches. In both cases the corrosion sets in here because the lube is pushed out of the contact areas and (because it is too sticky) it doesn't re-coat such exposed surfaces properly. Because it doesn't have enough corrosion inhibitors in it, either road salt mixed in with the moisture or the acidity that is created once corrosion starts will corrupt the remaining grease in those regions and everything turns bad.

In general (with hubs that are reasonably well sealed) I'd suggest that adding a little more than you might think is a less bad thing to do than being miserly with the lube. However two reasons why not to do this would be a) if you have a drum brake that works dry (eg some SA and SRAM hubs) or if b) any lube leakage is going to be a big problem (belt drive, carpets, clothes, etc etc).

If you want to know if you have done a good job, ride the bike a few hundred miles and inspect the internal again. You should see that everything inside the hub is nicely coated with lube, such that you can't handle any part of it without getting your fingers covered in the stuff. [It should look as if lube would come dripping off the internal if you gave it a good shake]. If there has been no leakage, and it wouldn't be a big problem if there were, add some more, or add gear oil to the mix.

cheers
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Re: IGH lubrication; a smoking gun.

Post by Suffolker »

@Brucey

Thanks for that comprehensive advice, which tells me exactly what I need to know.

There seems to be a lot of advice around on Shimano hubs which suggests dunking the thing in their oil, or ATF etc., and then putting masses of another grease on the races. Now you point it out, the interactions between the two may not be very good.

I'll be doing this work on the Alfine in the next day or two; after which I'll be considering how to deal with my S-A X-RD8 in such a way that the hub brake remains ungreased.
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Re: IGH lubrication; a smoking gun.

Post by Samuel D »

Does anyone know where to find the old Shimano documentation on how to grease a Nexus 3-speed hub? I am aware of the documentation showing the new oil-dipping procedure. I’m hoping the greasing procedure will cost less to do at home. The oil seems to come in a 1-litre format with dipping container and costs a lot even from Germany.
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Re: IGH lubrication; a smoking gun.

Post by Brucey »

I think the documentation you seek can be found using the wayback machine. It might be linked to on Sheldon Brown.

However IMHO I can't see the point in doing it as per shimano's instructions, either way: The oil dipping technique is for convenience in bike shops rather than quality of lubrication per se and it is far from ideal for an N3 hub anyway. By definition the oil will soak into the remaining grease and a place where there will definitely be no grease because it gets pushed out (and therefore no oil after a short period of use) is in the pinion bushings. If you use Nexus hub gear grease then you need to strip the hub completely else the lube won't get to where it needs to go, and then in service if the lube fails at any point the hub will eat itself (as per earlier posts in this thread).

I would suggest that (again be generous if you can live with a little leakage) that you just whack a load of Land Rover SFG in there. IME N3 internals retain enough lube to last a year or two before it needs to be done again; the reason is that whilst there is no lip in the hubshell (like many Sachs/SRAM hubs) the N3 hub has a clip-on shield that effectively creates a lip that will deter all the lube from coming out (provided it isn't oil, which will seep out).

cheers
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Re: IGH lubrication; a smoking gun.

Post by Samuel D »

I see. So, in broad strokes, is the process for whacking in some semi-fluid grease the same as that for Suffolker’s Alfine 8?

To give some context, this is my girlfriend’s bicycle with a rollerbrake. The rear wheel was recently rebuilt around the hub following a collapse caused by a Deliveroo cyclist riding into the side of it. That sunk cost increases our incentive to keep this hub working well. She uses it to commute to work, 10–15 minutes each way. The hub has seen no maintenance since new except that I ensure the shift cable tension is always correct.

There is a port to add grease to the rollerbrake, so I’ll order some of the special grease for that too.

I have asked around and not found anyone in Paris willing to service this hub. This lends weight to interestedcp’s observations on page 1. Sad.
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Re: IGH lubrication; a smoking gun.

Post by Brucey »

Samuel D wrote:I see. So, in broad strokes, is the process for whacking in some semi-fluid grease the same as that for Suffolker’s Alfine 8?


pretty much

I have asked around and not found anyone in Paris willing to service this hub. This lends weight to interestedcp’s observations on page 1. Sad.


IGHs have never been that popular in France; it is the land of the derailleur after all.... :wink:

But also you should look at it from the LBS's perspective; there isn't much of an upside for them IMHO. They are probably not going to get rich by greasing people's 3s hubs, (cynically, if it make them last longer this merely delays a more lucrative replacement wheel sale.... :roll: ) and a significant fraction of people who might turn up wanting 'maintenance' only do so when they actually need 'repair' because they have already wrecked their hub through neglect and/or misuse. When lubricating it correctly doesn't work, (because the hub is already a box full of shrapnel) it is disappointment and recriminations all round...

cheers
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Re: IGH lubrication; a smoking gun.

Post by Samuel D »

To all interested parties: what do you think of Elliot Flowers’ comments on 31 August 2014 on this article?

If you agree with his comment #6, what oil would you suggest for the purpose?
Brucey
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Re: IGH lubrication; a smoking gun.

Post by Brucey »

6. ‘Wash’ the internals in oil. Work the hub manually, in a viscouse oil any metal will eventually move out in the oil suspension. A good 30 minutes of twisting should do it.


this is more or less what happens with the shimano dip if you agitate the internals. FWIW I think it won't work with every oil and it won't work very quickly in any event. Like any other cleaning system, it has to tread the tricky balance between cleaning efficiently and avoiding subsequent contamination of the lubricant with the cleaning agent. The better the oil (as a lubricant) you use for cleaning, the more of it can be tolerated as a contaminant in the long term lubricant fill, but the less well it will clean, all things being equal.

The underlying premise is that there are parts inside the hub that are wearing and that the life of the hub will be shortened if the wear debris is allowed to remain in the hub. This can and does happen, but IME it is not the most common cause of IGH failure. If there is a part inside the hub that is starting to break up, that part usually fails entirely before the wear debris has a chance to cause much collateral damage elsewhere. The worst wear and damage are usually caused by

1) a lack of lubricant
2) water ingress and subsequent corrosion
3) poor lubricant quality
4) lubricant that is too thick causing parts inside the hub not to move freely enough, and the lubricant to be locally depleted
5) the lubricant becoming contaminated with wear debris and causing collateral damage

So IMV although it is potentially important there are other priorities ahead of 'cleaning' per se.

With a well-sealed hub you could run a fill of gear oil for a few weeks and then drain it out again, thus providing a cleaning action. With an unsealed/badly sealed hub you can add oil and allow 'total loss' to provide a cleaning action; (this is what preserves so many old SA hubs, although it is messy). With a Nexus 3 you could add oil via the hollow axle for flushing purposes, and then follow up with SFG via the same route. However I would stress that any excess of oil in an N3 hub is almost certain to cause overnight leakage.

cheers
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