Penrite SF Grease for Alfine 8?

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kalovsky
Posts: 6
Joined: 29 Nov 2018, 2:37pm

Re: Penrite SF Grease for Alfine 8?

Postby kalovsky » 10 Dec 2018, 4:04pm

Opened up my hub, including splitting the halves to see what was inside. Sure enough, some pretty thick clumps of green/grey mush was in there. Soaked in kerosene to get rid of it all, dried it out, soaked in gear oil, added just a bit of bearing grease on the races and filled with about 50mL of gear oil before closing it up. Maybe a tablespoon of oil dripped out overnight.

So far today, no skipping or engagement issues at all so far. Shifting more precise than it's ever been.

Thanks for the great advice. I bought this hub used so not sure what type(s) of grease were used in the past, but clearly it hardened and then my addition of gear oil loosened it up enough to cause issues.

Brucey
Posts: 35172
Joined: 4 Jan 2012, 6:25pm

Re: Penrite SF Grease for Alfine 8?

Postby Brucey » 10 Dec 2018, 4:50pm

I'm glad it worked out for you; dried grease is an absolute menace in these hubs, and some folk ride for long enough (hoping for the best instead of doing something about it) that the hub is damaged. It looks like you have avoided that and I expect you to get good service from the hub now.

cheers
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buffet
Posts: 17
Joined: 3 Jan 2019, 6:00pm

Re: Penrite SF Grease for Alfine 8?

Postby buffet » 3 Jan 2019, 6:12pm

Brucey,

I have an Alfine 8 (most recent one, the 7001-8 version) with about 200km on it. After reading many negative reviews on the factory grease, I want to do some pre-emptive maintenance. Since the hub is quite new, I want to inject some gear oil on the LH side according to your recommendations. 2 questions here:
- any EP90 gear oil will do the job? (I actually have 50ml Alfine 11 oil laying around, but I'm afraid that it's not thick enough for not waterproof Alfine 8)
- should I apply some standard multi-purpose grease (like the green Shimano stuff) on the LH bearings before putting back the cone&locknut to make sure it's keeps the oil in and water out?

Anything else I should be aware of? (such as your advice not to lift the wheel up during this procedure which I saw in another related thread)

Brucey
Posts: 35172
Joined: 4 Jan 2012, 6:25pm

Re: Penrite SF Grease for Alfine 8?

Postby Brucey » 3 Jan 2019, 8:30pm

technically what you suggest is fine but there is a snag; the hub has a two-year warranty on it that will be voided if you (very obviously) depart from shimano's recommended service regime and the hub then breaks.

Regarding grease in the LH bearing; this will eventually mix with oil in the hub anyway, so any effect might only be temporary depending on what is in the main part of the hub. In alfine hubs there is a lip seal and if this is in good condition it will retain oil or SFG quite well enough. If it is in poor condition then a thicker SFG or a standard grease might be best in the LH bearing because otherwise leakage rates (risking contamination of the disc brake) might be too high otherwise.

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

buffet
Posts: 17
Joined: 3 Jan 2019, 6:00pm

Re: Penrite SF Grease for Alfine 8?

Postby buffet » 3 Jan 2019, 8:49pm

Brucey wrote:technically what you suggest is fine but there is a snag; the hub has a two-year warranty on it that will be voided if you (very obviously) depart from shimano's recommended service regime and the hub then breaks.

cheers


I don't think that waiting while my hub rots because of bizarre choice of factory lubrication is a good idea (I doubt they will replace a rusty hub anyway) Anyway, I think if you service the hub the Shimano way (oil dunk) you will void the warranty if you do it anywhere outside of Shimano-certified LBS (which can hardly be found where I live).

Quick question on the procedure - is it fine not to use the bench vice for disassembling the hub? (I know it's convenient, but I don't own one.)

Brucey
Posts: 35172
Joined: 4 Jan 2012, 6:25pm

Re: Penrite SF Grease for Alfine 8?

Postby Brucey » 3 Jan 2019, 10:52pm

I agree that leaving the hub to rot isn't a brilliant idea but you should at least be aware of the potential warranty implications of doing things that are obviously not as per shimano's procedures.

Not using a bench vice just makes it slightly more awkward to do the job. In particular it increases the chances that the RH bearings will (quite unnecessarily) become dislodged. This carries with it a small chance (even smaller with a new hub) that something (eg a ball out of the main ring bearing) will get dislodged.

Once the internal has (even briefly) moved out of its seating on the RHS, the only way to be 100% sure that everything is where it should be when the hub is reassembled is to do a lot more in the way of disassembly, thus turning a simple job into one that is a lot more complicated.

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

kalovsky
Posts: 6
Joined: 29 Nov 2018, 2:37pm

Re: Penrite SF Grease for Alfine 8?

Postby kalovsky » 4 Jan 2019, 6:38pm

It's been almost a month since I washed out all the hardened grease and filled with 50mL of gear oil and has been running flawlessly.

Only concern to report is that after a little initial oil leakage it stopped, but then a week or so later quite a bit dripped out. I'm concerned that there might not be much oil left so considering filling up again, but looking into a better sealing job.

All leaking is from the drive side so considering some heavy marine grease on at least the outside of that main large ring bearing.

I also saw mention of "Sheldon Brown's Silicone" method, but not sure what this is and Google hasn't helped. Does anyone have a link, and would this work on the large drive side bearing?

Thanks!

alexnharvey
Posts: 752
Joined: 10 Jan 2014, 8:39am

Re: Penrite SF Grease for Alfine 8?

Postby alexnharvey » 4 Jan 2019, 6:58pm

I think you'd be better investing in a few quid of semi-fluid gear box grease than trying to seal it up with silicone which I assume is what is referred to by the Sheldon method. I world guess you'd be putting silicone where the large seal attached to the hub? I imagine it would be very hard to get good adhesion on surfaces contaminated with grease and oil. OTOH, I do put a wrap of insulating tape around the outside of the hub to hub seal join and that lasts about a year or two and may help retention.

The bodge method is to mix gear oil with some grease to thicken it up. This works ok in my experience, there was still a good coating of grease-oil mix in the hub and on the internals when I opened it up again. A proper thixotropic/semi fluid gearbox grease would be better still I think.
Last edited by alexnharvey on 4 Jan 2019, 7:00pm, edited 1 time in total.

Brucey
Posts: 35172
Joined: 4 Jan 2012, 6:25pm

Re: Penrite SF Grease for Alfine 8?

Postby Brucey » 4 Jan 2019, 7:00pm

the silicone method is for parts that have no seals rather than some seals that are not working correctly and anyway is unlikely to make the parts oil-tight. It can be used to make almost-contact seals in things like the labyrinths on SA hubs too. Essentially you clean one part of an assembly , coat the other (eg the cone or dust shield attached to a cone) with Vaseline or grease, and assemble the parts with layer of RTV silicone sealant between. When this has cured the result should be a contact seal of a kind. Any initial drag soon reduced as the RTV wears away in use.

Alfine hubs have a rubber seal built into the plastic cover over the ring bearing, which mates with the hubshell. If this leaks then the rubber seal is damaged or the parts are not assembled correctly; it should be oil-tight here. The same cover also has a lip seal on the ID against the driver. This seal is less good but usually only leaks if the seal is badly damaged, the hub is overfilled, or the bike is left on its side. Oil can also leak from the end of the driver; both shift controls and the axle have seals on them but these seals are never oil-tight. Again they will leak if the hub is overfilled or the bike is leant the wrong way overnight.

Be aware that a little leakage looks like a lot; you may have more lube left inside the hub than you expect. However if leakage is persistent then less lube and/or a slightly thicker lube is indicated. Using a SFG works well even on Nexus 8 hubs which have poorer sealing. However adding SFG to a hub that contains dried grease occasionally results in a mixture that is too thick. Adding SFG to a hub containing much oil will probably make a mixture that is too thin.

Note that any change in temperature results in air passing in and out of the hub; the hub normally 'breathes' via the imperfect seals on the RHS. If there is lube near those seals, bringing the bike into the warm may push some of the lube out of the hub. In a similar vein taking a warm bike into the cold rain encourages the hub to suck water into it as the air inside contracts.

Note also that adding a thick grease to the ring bearing won't stop leakage; the grease mixes with oil and anyway the oil will bypass even an immiscible grease and find a way out of the hub if there is one.

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

buffet
Posts: 17
Joined: 3 Jan 2019, 6:00pm

Re: Penrite SF Grease for Alfine 8?

Postby buffet » 4 Jan 2019, 10:15pm

Has anyone compared the seals on Alfine 8 vs Alfine 11? Considering the number of reports of Alfine 11 leaking oil, I'd assume they are quite similar.

buffet
Posts: 17
Joined: 3 Jan 2019, 6:00pm

Re: Penrite SF Grease for Alfine 8?

Postby buffet » 6 Jan 2019, 7:28pm

Brucey,

Is there a clear guideline on LH cone and locknut tightening torque? I don't have a torque wrench for 15mm anyway, so maybe you could explain it in layman's terms?

Brucey
Posts: 35172
Joined: 4 Jan 2012, 6:25pm

Re: Penrite SF Grease for Alfine 8?

Postby Brucey » 6 Jan 2019, 8:56pm

the trick is to make it so that the bearing only just has no slack in it once the locknut is tightened. To do this reliably (i.e. with minimum preload on the bearings) requires that you increment towards a play free adjustment from one that is too loose.

A method that works quite well is to finger tighten the cone, back it out about 1/4 turn, then tighten the locknut whilst holding the cone steady. There should be a little bit of play in the bearings. Hold the cone steady again, loosen the locknut, increment the cone inwards by a tiny fraction of a turn and retighten the locknut. Repeat as necessary; the first time you get an adjustment with no play in the bearings, that is it, you are done.

Left-side locknuts need to be about 1/3 as tight as track nuts.

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

buffet
Posts: 17
Joined: 3 Jan 2019, 6:00pm

Re: Penrite SF Grease for Alfine 8?

Postby buffet » 6 Jan 2019, 9:19pm

Thanks, Brucey, great explanation! I will inject 25cc of Alfine 11 oil that I have laying around.

kalovsky
Posts: 6
Joined: 29 Nov 2018, 2:37pm

Re: Penrite SF Grease for Alfine 8?

Postby kalovsky » 7 Jan 2019, 9:36pm

I'm considering trying out the semi-fluid grease so just wondering how much would the Alfine hub require. Would I just cover the gears like a grease or pour in 50mL like with the gear oil?

Brucey
Posts: 35172
Joined: 4 Jan 2012, 6:25pm

Re: Penrite SF Grease for Alfine 8?

Postby Brucey » 7 Jan 2019, 11:25pm

kalovsky wrote:I'm considering trying out the semi-fluid grease so just wondering how much would the Alfine hub require. Would I just cover the gears like a grease or pour in 50mL like with the gear oil?


It rather depends how dried out the grease is inside your hub. If you add SFG to dried grease, you can end up with a mixture of grease that is too thick; it is OK (sort of) to have a thin smear of thick grease over the workings (that is more or less how the hubs are from new) but if you are going to have a lot more lubricant inside the hub, it is at least desirable if not necessary for that lubricant to be a good deal more fluid too.

Thus I'd suggest that you add oil, run the hub for a while, then add SFG, or alternatively dilute the SFG with oil (to allow for the potentially quite dry grease that is already inside the hub) and add that.

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