Alfine 8 speed hub leaking?

[Blackredgold1964]

Dear all,
Would this hub be leaking oil? Today my wife cycled and there was a "knocking" noise at every pedal stroke. This would indicate rather something wrong with the bottom bracket. However the hub worries me. I've swiped away the oil on the non drive side a day ago and now it's back. Please see photo.

I've had it serviced last month. Now we're cycling 7 weeks through Costa Rica, which is very nice but few bike shops who'd be able to help.
Any advice welcome.

[rualexander]

That looks like a Nexus hub rather than an Alfine 8 hub, but in any case both of them normally have grease in them rather than oil, unless you've previously had the grease cleaned out and replaced with an oil of some kind, in which case it may well leak a bit as the hubs are not sealed for oil.

[Brucey]

yup. On the left side there is a labyrinth that works OK with grease but lets oil out rather easily. I would say that as long as there is oil coming out you are OK but if it stops coming out you have a LH bearing that might perhaps run dry after a few more hundred miles unless it is greased.

If the hubs have lots of oil in and the bike were laid down on the left side (eg in transit) then some leakage is inevitable.

FWIW in these Nexus hubs I prefer to use a semi-fluid grease because it doesn't leak out like oil does.

cheers

[hemo]

Alfine 8 is grease lubed and thought Nexus 8 is oil lubed.

My Alfine 8 I also use a liquid grease.

[Blackredgold1964]

Dear all,
Thanks for the replies, very useful, and a great relieve for me. The hub is Nexus (premium).
Indeed, we did two transfers with bikes lying non-drive side down. Hopefully that's it! Off to Panama in two days then.

[Brucey]

Alfine 8 is grease lubed and thought Nexus 8 is oil lubed.

My Alfine 8 I also use a liquid grease.

Nexus 8 (and Alfine 8 ) are 'selectively lubed' in the factory using a rather thick and gungy grease. For the last few years the grease has been white and before that the grease was dark-coloured. The white stuff appears to have little resistance to water and no resistance to road salt whatsoever. Once the water gets into one part of the hub that part of the hub will fail and the remaining grease will just stay put on the other parts; I have seen hubs where the axle assy looked like new, with nice clean grease, but elsewhere the hub was rusted solid. Any corrosion appears to generate a weak acid and that turns the grease into cheese.

The recommended service procedure is to dunk the innards in a ridiculously expensive oil, which is meant to 'refresh' the grease. The best I can say for this is that if it didn't need doing anyway, it is unlikely to do much harm. If you just sling a load of oil in the hub you will achieve a similar result. With a Nexus hub if you overdo it you end up with a hub that can leak oil; there is no contact seal on the left side. Alfine models are better sealed (the seals are better on the left side and at the ring bearing) and these models can often be run in a sloppy mix that is mostly oil without excessive leakage. The right SFG will work OK in either type of hub.

cheers

[Blackredgold1964]

Thanks again, will keep in mind for future maintenance.

[Eric the Red]

My Alfine should always be grease-packed. Some people have been using car automatic transmision fluid, and this leaks out onto the disc and kills the braking/pads.