IGH lubrication; a smoking gun.

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Brucey
Posts: 42990
Joined: 4 Jan 2012, 6:25pm

Re: IGH lubrication; a smoking gun.

Postby Brucey » 29 Aug 2019, 8:26am

2Phat4Rapha wrote:
Brucey wrote:
2Phat4Rapha wrote:NGAT.JPG

Never mind NIG, how about no gears at all?


I've seen that happen a few times. What usually causes it is either no lube or no hardening. When it does happen you normally still have the middle gear, but not 1 or 3.

BTW that axle is a NIG SA 3s one made by SunRace in Taiwan. The design is inherently stronger than the old AW axle (with a riveted sun pinion) but I am not sure the current QA is quite as good as it could be. I've seen a few duff parts, more than I'd like.

cheers


Thanks as always Brucey. Internals were dry as a bone. I would have expected the planet pinions to be damaged also but they were fine. Even measured them with a Mitutoyo micrometer against new ones. Perhaps also points to insufficient hardening. There might have been a middle gear but it was just a hub on its own as an eBay purchase for refurb so can't say for certain.


BTW its worth noting that even if the axle is as hard as the pinions, the sun pinion would still be expected to wear about x4 as fast; it has four pinions bearing against it, so it is somewhat outnumbered.

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

2Phat4Rapha
Posts: 30
Joined: 1 Dec 2010, 1:58pm

Re: IGH lubrication; a smoking gun.

Postby 2Phat4Rapha » 25 Jan 2020, 2:28pm

Another dry AW3. What's showing in the pic is asymmetric wear on the pawls. Wear on the low gear pawls is quite obvious, not so much on the gear ring pawls but it is there. I am wondering if this might be symptomatic of a bent axle as it looks slightly so when rotating.
Image Attachments
aw3PawlWear.JPG

3speednut
Posts: 32
Joined: 6 Apr 2015, 7:32pm

Re: IGH lubrication; a smoking gun.

Postby 3speednut » 26 Jan 2020, 9:32pm

Not directly a lubrication question ,but there is mention in this thread of the Shimano Nexis 8 speed ,I have one myself but find it very inefficient compared to the Sram S7 I have been using for the past 4 years ,I have had the Shimano on the same bike ,had the hub from new and it was like that from the start and only ran it for about 8 months ,its been removed from the hub shell and found to be lacking much grease so following Sheldons advise on his website I think it was at the time (5 years ago ) I regreased and oiled it and checked for tight bearings or anything wrong ,I actually tried running it with slightly loose axle bearings for a while but nothing improved it and I swapped to using the Sram S7 witch I found to be a lot more efficient ,does any one else find this with their Nexus 8 ,am I perhaps over sensitive to wasted energy whilst pedalling or could there be something wrong with my hub ,I like the gear change on the Nexus ,very smooth and the cable removal is better too ,so its not all bad ,I want to like it and use again but it will stay in the attic for now.

Brucey
Posts: 42990
Joined: 4 Jan 2012, 6:25pm

Re: IGH lubrication; a smoking gun.

Postby Brucey » 27 Jan 2020, 12:15pm

Nexus 8 uses two gear trains in series in the lowest four gears which is not very efficient.

Gear 5 is direct drive, and the only drag ought to be from roller clutches. However the least efficient gear is gear 4, which is substantially less efficient.

If you ride around mostly in gear 3 and gear 4, it can be hard work. In gear 5 and gear 6 the efficiency is a lot better.

Note that most Nexus 8 hubs have plain bearings on the planet pinions, but some (so-called 'premium' models) have roller bearings which are a lot more efficient (by about 10% or more).

If you can adjust the sprocket size so that you use gear 5 most of the time, then this will improve the gears efficiency. So will using a SFG or heavy oil instead of a gungy grease.

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

Brucey
Posts: 42990
Joined: 4 Jan 2012, 6:25pm

Re: IGH lubrication; a smoking gun.

Postby Brucey » 27 Jan 2020, 12:18pm

2Phat4Rapha wrote:Another dry AW3. What's showing in the pic is asymmetric wear on the pawls. Wear on the low gear pawls is quite obvious, not so much on the gear ring pawls but it is there. I am wondering if this might be symptomatic of a bent axle as it looks slightly so when rotating.


The low gear pawls have a mark on the back from where they are overrun ( in gears 2 and 3, also when freewheeling in any gear). The wear mark is asymmetric most probably because the pawl spring is loading the pawl on one side and not the other. Uneven wear on the loaded face of the pawl would be more of a worry.

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

3speednut
Posts: 32
Joined: 6 Apr 2015, 7:32pm

Re: IGH lubrication; a smoking gun.

Postby 3speednut » 27 Jan 2020, 8:15pm

Brucey wrote:Nexus 8 uses two gear trains in series in the lowest four gears which is not very efficient.

Gear 5 is direct drive, and the only drag ought to be from roller clutches. However the least efficient gear is gear 4, which is substantially less efficient.

If you ride around mostly in gear 3 and gear 4, it can be hard work. In gear 5 and gear 6 the efficiency is a lot better.

Note that most Nexus 8 hubs have plain bearings on the planet pinions, but some (so-called 'premium' models) have roller bearings which are a lot more efficient (by about 10% or more).

If you can adjust the sprocket size so that you use gear 5 most of the time, then this will improve the gears efficiency. So will using a SFG or heavy oil instead of a gungy grease.

cheers

Thanks Brucey ,I do agree with your comments about the difference between 4th and 5th very noticeable ,my commute is quite hilly and I do use all the gears so the Nexus 8 is very noticeably more harder work perhaps as you say gear it lower to make use of the more efficient 5th and 6th .

Brucey
Posts: 42990
Joined: 4 Jan 2012, 6:25pm

Re: IGH lubrication; a smoking gun.

Postby Brucey » 28 Jan 2020, 2:20pm

oh, I forgot to mention that the efficiency in gear 1 in a nexus 8 is also pretty good; the second gear train is not doing anything in this gear so it is only one gear train that is being used.

BTW if you don't have a smooth pedal stroke, hubs with roller clutches can cost you more than you might expect; they often feel very slightly squashy with every pedal stroke. I prefer the feel of hubs with pawl drives; possibly you do too; the SRAM S7 has pawls that do the driving.

Note that efficiency tests are usually done with a continuous drive, not a pulsy one like real pedalling. Thus the true extent of losses in roller clutches is unknown, but I've slowly come to the conclusion that, in use, they do feel rather lossy to me.

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

3speednut
Posts: 32
Joined: 6 Apr 2015, 7:32pm

Re: IGH lubrication; a smoking gun.

Postby 3speednut » 29 Jan 2020, 6:23am

Yes the same thought had crossed my mind, having pulled different IHG apart over the years the only main difference i could see was the roller clutches rather than paws, give me the tick ticking of a AW 3speed rather than silence if you sacrifice some efficiency, i do actually like the ticking f the AW3speed anyway, cheers.

JakobW
Posts: 423
Joined: 9 Jun 2014, 1:26pm
Location: The glorious West Midlands

Re: IGH lubrication; a smoking gun.

Postby JakobW » 2 Feb 2020, 3:03pm

My OH's been offered a bike with a Nexus SG-C6001-8 disc braked hub for a good price - apparently it's spent most of its life in a garage, but I doubt it's had much maintenance. My OH wants to use it as an all-weather commuter, so I suspect better lubrication is a good idea. If I've understood Brucey's advice correctly, the easiest solution is just to put the wheel in a vice and back off the LH cones enough to squirt in 30ccs of gear oil or SFG?

Brucey
Posts: 42990
Joined: 4 Jan 2012, 6:25pm

Re: IGH lubrication; a smoking gun.

Postby Brucey » 2 Feb 2020, 3:16pm

more or less. I'd advocate gear oil in the first instance because you don't know what kind of a sticky mess is in there at present; SFG plus a sticky mess can just result in a bigger sticky mess than you started with.

After a few months of use with the gear oil inside the hub (which may leak out BTW) you can more safely add SFG.

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

CXRAndy
Posts: 50
Joined: 18 Aug 2019, 1:45pm

Re: IGH lubrication; a smoking gun.

Postby CXRAndy » 5 Mar 2020, 9:48am

Hi Brucey

Ive got myself a new SG 7051 11speed to lace up. Is there any servicing that needs to do to improve service life, before lacing?

Brucey
Posts: 42990
Joined: 4 Jan 2012, 6:25pm

Re: IGH lubrication; a smoking gun.

Postby Brucey » 5 Mar 2020, 10:12am

not really; you can do most things to the hub once it is in the wheel, just as (if not more) easily.

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

CXRAndy
Posts: 50
Joined: 18 Aug 2019, 1:45pm

Re: IGH lubrication; a smoking gun.

Postby CXRAndy » 5 Mar 2020, 11:24am

Ta
:wink:

rogerzilla
Posts: 1603
Joined: 9 Jun 2008, 8:06pm

Re: IGH lubrication; a smoking gun.

Postby rogerzilla » 17 May 2020, 4:38pm

Here's an obscure one: can the planetary gears of a Sachs Duomatic 102 be lubricated with SRAM IGH grease* (the straw-coloured stuff that comes in a metal toothpaste tube)? Normally there are three types of lubricant in these hubs:

1. Planetary gears: oil - less than with an SA hub, you basically coat the components in oil as you assemble the hub, allow the excess to drip off, and oil very sparingly and infrequently in use
2. Axle bearings: lithium grease
3. Coaster brake ring: very high temperature brake grease (some recommend Vaseline for this model, with its bronze brake element; I use Cera-Tec automotive brake grease)

The problem with using oil, even sparingly, is that all these greases inevitably mix, with the oil diluting the greases and causing them to ooze out of the ends.

*no longer made, along with any SRAM internally-geared hubs or spare parts, but I have some