SRAM 3 speed hub

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sfs
Posts: 22
Joined: 22 Mar 2016, 8:25am

SRAM 3 speed hub

Post by sfs »

hello all, i have a SRAM 3 speed hub on a Brompton - i know they are now discontinued!

testing the 3 speed shifter when the bike is stationary, all works fine when running the chain backwards, but when i am cycling and change gear (slight pedal backwards) the chain sags

i can only think this is due to the hub not running freely, so it doesn't turn anticlockwise as readily as the chainwheel? in which case maybe it needs some lubrication? I read on Sheldon Brown about oiling by dismantling the gear case, which sounds a bit extreme - hoping another forum user here has an idea / experience of doing this by running oil somewhere? these hubs don't have an oil port

???

thank you, stefano
Brucey
Posts: 44521
Joined: 4 Jan 2012, 6:25pm

Re: SRAM 3 speed hub

Post by Brucey »

you can add lube via the hollow axle.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
hoogerbooger
Posts: 673
Joined: 14 Jun 2009, 11:27am
Location: In Wales

Re: SRAM 3 speed hub

Post by hoogerbooger »

,?? But the SRAM 3 speed on a Brompton is grease lubricated and poorly sealed if you wish to change to oil.....so it will leak freely, locking you in to a dribbly future requiring frequent re-oiling and a ban from keeping it in the living room.

So if the issue is poor lubrication should not grease lubrication be considered 1st. My understanding is also that to do it properly would need complete dismantling, degreaseing, reassembly using the appropriate grease...so not for the feint hearted.....but it is fairly straight forward to remove the mechanism from the hub shell to consider if it is dry and grease lacking.

I am also wondering,but not sure if over tight lock nuts on the right hand side can cause that sympton ( warning I'm a tree hugger, not a bike mechanic)
old fangled
Brucey
Posts: 44521
Joined: 4 Jan 2012, 6:25pm

Re: SRAM 3 speed hub

Post by Brucey »

the grease in SRAM hubs commonly dries out and makes the hub sticky exactly as the OP described. Adding oil can free them up OK, but obviously too much oil will make a mess as described. It is 'worth a go' though.

FWIW it isn't a big job to remove the sprocket and the dust covers associated with it, which will allow a little oil to be added directly to the RH ring bearing. Similarly a little spray lube can be used on the other side (which is another large diameter bearing in this model of hub). This doesn't necessarily offer a permanent solution but it will at least confirm the diagnosis (or not) of sticky grease, since the large diameter bearings are the ones that most easily create drag when freewheeling.

IIRC you need two 22mm cone spanners if you want to strip the hub using normal means or adjust the bearings in that model of SRAM hub, which is a bit of a PITA. However you can (with fewer tools) dismantle the hub from the RH side without losing the bearing adjustment, because the RH cone fits against a shoulder on the axle.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
sfs
Posts: 22
Joined: 22 Mar 2016, 8:25am

Re: SRAM 3 speed hub

Post by sfs »

thank you both for your replies,

i didn't think of oiling through the hollow axle - and it seemed to have worked!

only problem now is that the oil on my fingers is seeping inbetween the keys on my keyboard.....

kind regards, stefano
hoogerbooger
Posts: 673
Joined: 14 Jun 2009, 11:27am
Location: In Wales

Re: SRAM 3 speed hub

Post by hoogerbooger »

yes 2 x 22mm locknuts on lhs

the following link should have an exploded view/guidance for the T3 hub to help you decide if you want to look inside:
https://cdn.sram.com/sites/default/file ... h-reva.pdf
old fangled
rmurphy195
Posts: 2199
Joined: 20 May 2011, 11:23am
Location: South Birmingham

Re: SRAM 3 speed hub

Post by rmurphy195 »

If you use the Brommie as intended the oil will negate some of the uses i.e storing the bike under the desk at work, or under tablesin cafes etc. and alsolead to complaints about its use in shops 'cos of other customers getting theier clothe oily if they brush against it.Maybe we have there a little enlightenment in the "I should be able to take my folder into a shop" debate, if shop owners have had complaints about such problems?

either way once the cause has been established then a grease repack (or bike shop service) is the way to go long-term.
Brompton, Condor Heritage, creaky joints and thinning white (formerly grey) hair
""You know you're getting old when it's easier to ride a bike than to get on and off it" - quote from observant jogger !
hoogerbooger
Posts: 673
Joined: 14 Jun 2009, 11:27am
Location: In Wales

Re: SRAM 3 speed hub

Post by hoogerbooger »

As I understand from previous posts, adding a little oil via the hole in the axle having removed the gear change chain...means that tje oil arrives at the heart of the mechanism and then spins out. So a pretty good way to get oil to key surfaces. It will gradually mix with the dry grease which will return to a more grease like form and might find it's way back on to some of the places that need greasing. But might just spin out to places it isn't needed.The remaining grease may have already spun out so that some surface are essential not greased. As you add more oil over time you will spin out the oil grease mixture to become an oil dependant beast waiting for the next oil 'fix'. However you have a reasonable chance of the surfaces needing lubrication....being lubricated.

The oil will find it's way into the axle bearings flushing out the grease there too. I recall the left race is cut into the hub shell (as is the right hand drive ball race)and is essentially not sealed just covered by the end cap ? (Check exploded view) If you are out and about much when it rains the is risk of water getting to the axle being and oil is presumably less useful than grease. If you end up with a pitted race in the hub it could be an end of life event.(for the hub that is)

I have had a few issues in heavy rain when I had that hub on my Brompton. In fact I recall the sort of chain drag/ sag referred to in the OP. I was not sure why this happened in the rain, but water entry is a suspect, although must have then escaped later as when I eventually got brave enough to take the hub mech out of the shell there was still enough grease seemingly. I would worry more if I was oil dependant for lube.
Last edited by hoogerbooger on 19 Dec 2020, 1:33pm, edited 2 times in total.
old fangled
Cyckelgalen
Posts: 221
Joined: 21 Sep 2018, 11:29am

Re: SRAM 3 speed hub

Post by Cyckelgalen »

Injecting oil may appear as a good solution because it dilutes old grease clogging the hub, but in the long run, oil cannot provide adequate lubrication on a hub designed to be lubricated with grease. As mentioned above, unlike hubs such as Rohloff or Alfine 11, this hub lacks any sealing to retain a permanent oil bath.

Your hub is an earlier iteration of the SRAM dual drive, but appart fron the fact that yours is chain operated and later hubs use a pull rod (and clickbox), I presume that the innards and assembly are quite similar if not identical. If that is the case you can easily remove the whole mechanism from the hub shell to remove old grease and pack with propper fresh grease.

There is a YouTube video that shows the whole disassembly, it is in Korean but still very helpful without understanding a word.
If you don't feel confident you don't need to take everything appart as the video shows, you could lay the whole internal assembly in a solvent long enough to soften up and cleanse the old grease.
The only thing that requires precision on putting it back together is adjusting the bearing. This is not a quick release axel but it is a hollow axel nonetheless. I am not sure if it compresses when the locknuts are tightened like QR hollow axels do. Check info on adjusting cone bearings leaving a bit of play to allowi for axel compression, it has been discussed and explained many times in the forum.

https://m.youtube.com/watch?v=OC7SYR666B8

By the way, the cone wrench he uses appears to be smaller than the 22 mm mentioned above.
Brucey
Posts: 44521
Joined: 4 Jan 2012, 6:25pm

Re: SRAM 3 speed hub

Post by Brucey »

the hub is a bog standard torpedo 3s, of which there were millions made. The dual drive design is only very loosely based on this hub, and (especially if you are not familiar with hub gears), any dual drive info is likely to be worse than useless.

There is no issue with axle compression in any hub which uses track nuts, only ones with a skewer up the middle of the hollow axle.

You can of course dismantle the hub without affecting the bearing adjustment as described previously.

If you want to provide reasonable long-term lubrication without disassembling the hub, you can use semi-fluid grease inside it, again added via the axle. However if the hub already has dried grease in it, you shouldn't add SFG without having added some oil first, else you can end up with a bigger sticky mess than you started with.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
oldmanwitholdcycles
Posts: 1
Joined: 10 May 2023, 4:16pm

Re: SRAM 3 speed hub

Post by oldmanwitholdcycles »

'.... oil cannot provide adequate lubrication on a hub designed to be lubricated with grease ....'

But the three speed is designed for oil lubrication!

# The original design (the '515') was supplied in the sixties with an oil nipple.
# Later, the brake shoe was changed from brass to steel (or cast iron, presumably), for sake of money, I think. That pairing, of course, needed strong medicine for not to gall (seize? -- my English, sorry ....) and was supplied then with a 'life-time' grease filling, while the hub itself still had its oil nipple.
# For cost reasons, again, the nipple was abandoned little later.
# In the seventies, as a safety measure, the unintentional idle between second and third gear was removed by a design change of the shifting claws (is this English, again?), and the resulting hub re-named to H3111S. Many parts of this are still the same as in the former 515.
# That S-hub was updated some times in terms of production efficiency (the shell mostly) and at one point, after the szstem was established at the five S5 and seven speed S7 hubs, the switching gear was changed from chain pulling to a pushrod.
# S5 and S7 are extensions of the given principle, more or less.
# Donaskme about newer designs.

You are absolutely right to say that the grease gets clogged in the hubs after ten years or twenty. As a result, fresh grease sits happily in any place where no motion occurs, while the moving parts run dry at some time (even then, the hub survives quite a long time). Mostly in danger is the compact roller bearing (has it 10 pieces of 7/32" balls?) 'under' the sprocket -- this enjoys as a VIP service to receive a refreshing surge of oil through the 'sealing gap' (ha ha) any time when the rear wheel is removed from the bike. The rest of the hub can live with a dash of oil along the hollow of the axle once in a blue moon; the problem is less that oil seeps out (this is highly wanted in a badly sealed design -- excess oil sweeps ingressing dirt and water back into the environment) but more that the very special grease in the brake shoe gets washed away in the process -- I never found any replacement lubricant to make a seizing back-pedal brake work smoothly again, while the real McCoy translates to roughly 180 € per kg -- doesanybodybychance ..... ?

When I have to do maintenance on a wheel with a three speed hub, after removal of the switching chain or 'skewer' (ti hi) I use to fill the hollow axle up to the brim with oil and let it seep into the hub; by doing that three times altogether I may fill in 1 ccm perhaps. My preferred lub is gearbox oil (surprise, surprise ....) SAE80-W90, of which I once bought a gallon can for a completely different (car) matter and which will outlast me supposedly. Any pressure-resistant, preferably sticky, oil will be preferred, while, on the other hand, the hub of course was designed to be used with the thinnish sewing-machine-oil of our gramps. In the bottom line, I think the hub will run on anything oily which doesn't run away or clog, so, as long as any little lubrication is given, the hub will work.

As pointed out, the first point to wear out is the ball bearing 'under' the sprocket, and of this it's the cone which can easily replaced when a new one is at hand. I bought a dozen or like some twenty years ago, dunno if they are available again -- a workmate fitted his 'Dutch bike' with a far east rip-off of a SRAM three-speed .... when such is available, there must be spare parts circulating .... ?
To replace that cone would be, for me, the one and only opportunity to open the hub from the sprocket side, since this is highly discouraged by the 80's manual which, I remember, says that it is easy then to crack the tiny cross-piece which takes the switching chain (which thread is, by the way, the same as on a spoke gauge 14).

Oiling the S5 or S7 is even less critical than any three-speed since their stepped design -- together with gravity -- prevent the oil to seep into the brake grease. Especially the S7 hubs from the nineties, when were cranked out to bikes sold by department and hardware stores, seem to suffer from clogging grease and are very, very grateful when getting oil via the hollow axle.

Best regards

Martin
Cyckelgalen
Posts: 221
Joined: 21 Sep 2018, 11:29am

Re: SRAM 3 speed hub

Post by Cyckelgalen »

I have two Sram dual drive hubs and I have opened, cleaned and packed them with grease with no issues. Easier than expected. Anyone can give it a go, taking photos at every step will help.
Above all, take notice of the position of the bearing cages, they are easy to reverse when you put it all back together. The bearings are cup and cone, and will need adjustment at the end.

All Sram IGH are Fichtel&Sachs designed. Sram bought the German company, but regretfully stopped manufacturing and dropped the brand only 3 years later, so lack of spare parts is definitely an issue.
Fichtel & Sachs had been making internal gear hubs for about a century, many sold rebranded in other markets. The 2 and 3 speed hubs that I know were all grease lubricated. Most IGH are grease lubricated, up to Shimano Nexus 8 and Alfine 8, and only the top end Alfine 11, Rohloff etc are sealed and oil lubricated.
The nipples you refer to are also used to inject grease, not necessarily oil. Sram, and others did not recommend any service intervals to replace the grease, so they really are supposed to be lubricated for life! Sealed hubs with an oil bath will have an opening to allow regular oil replacements, just like a car engine.

https://lecycleur.com/parts/history-of- ... w-success/
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