Author Topic: Accidently submerged son28 dynamo hub and Rohloff hub...  (Read 499 times)

Accidently submerged son28 dynamo hub and Rohloff hub...
« on: 13 January, 2022, 06:40:55 pm »
Hi,

I went out cycling last Sunday and came across a large ford unexpectedly in the dark which initially looked like a puddle. Unfortunately the ford went above the height of the hubs. The son 28 dynamo hub now sounds as though it has water in it, I was hoping for some ideas and also on the off chance whether it may sound like it has water in it because of the dynamo as can't remember even listing to this before? Wishful thinking perhaps! If it does have water in it can anyone suggest whether I can remove it or would it need to go back to Son in Germany for a service which would be a bit of a pain as it is under a year old. The dynamo is functioning perfectly but is just the sound that concerns me as if it does have water in there there is a concern that it may rust the magnets, etc.

The Rohloff seems to be functioning fine and no signs that water has got in on this but if anyone has any suggestions would be interested to read these?

Thank you

Wowbagger

  • Sylph
    • Musings of a Gentleman Cyclist
Re: Accidently submerged son28 dynamo hub and Rohloff hub...
« Reply #1 on: 13 January, 2022, 06:45:13 pm »
I can't imagine that there's anything wrong with the Rohloff. If in doubt, just change the oil.

I think my SON hub has been submerged before. It's certainly got very, very wet. It's still going without a service after almost 42000 miles.
Bach without a doubt.

Kim

  • Timelord
Re: Accidently submerged son28 dynamo hub and Rohloff hub...
« Reply #2 on: 13 January, 2022, 07:10:17 pm »
AIUI, SON hubs have a tube open to the inside of the axle, so that changes in air pressure don't compromise the seals.  I can imagine that sucking up some water if immersed in cold water.

ETA: See photos.

Might be worth taking the QR off and leaving it somewhere warm for a bit?

Re: Accidently submerged son28 dynamo hub and Rohloff hub...
« Reply #3 on: 13 January, 2022, 09:01:11 pm »
A Son hub can feel a bit rough as normal. I've just fitted mine for the winter and it felt terrible until I tightened up the QR.

Kim's advice is sensible as usual.
Tha rothaireachd math dhut.

Re: Accidently submerged son28 dynamo hub and Rohloff hub...
« Reply #4 on: 13 January, 2022, 09:38:46 pm »
Rohloff - I'd change the oil, if the flushing oil comes out milky, flush it again till it doesn't. If you only have one shot of flushing oil, it'd still be better to do it twice with half quantities.
Older hubs were better sealed at the cost of some efficiency, newer ones less so, I preferred the older version. Even with a newer one, it's unlikely a short ride through a ford would allow water to pass the seals, but it's an expensive hub to take chances with.
I have the older version of the SON hub, it survived being in a canal, still in use twenty years later.

Re: Accidently submerged son28 dynamo hub and Rohloff hub...
« Reply #5 on: 14 January, 2022, 09:38:16 am »
No idea about the Rohloff but I was under the impression that the SON design minimises water ingress.  I am sure that one of mine has been forded more than once and to be honest I never gave it a second thought.

Thinking about it: isn't internal condensation just as much of a potential issue?  I'm perhaps revealing my sheer ignorance about these things but hey ho.

Kim's suggestion seems like a good place to start.

arabella

  • no se porque yo no lo se
Re: Accidently submerged son28 dynamo hub and Rohloff hub...
« Reply #6 on: 14 January, 2022, 10:32:54 am »
fwiw, I rode into a deep puddle once and noticed a slow but steady stream of bubbles from my front hub.
I removed hub from puddle sharpish
in keeping with my just-too-late style of maintenance I've done nothing else (apart from the puddles, it was a warm dry August day)
dynamo still going strong at least 3.5 years later, probably 4.5 years even.
In the dark, all views are the same.

Re: Accidently submerged son28 dynamo hub and Rohloff hub...
« Reply #7 on: 14 January, 2022, 10:38:17 am »
I did similar with Shimano dynamo and a flood last winter.   Because you can service Shimano dynamos I opened up the hub and greased the bearings, same with rear hub.  The flood was so deep I got a wet bum on my recumbent. 

BFC

  • ACME Wheelwright
Re: Accidently submerged son28 dynamo hub and Rohloff hub...
« Reply #8 on: 14 January, 2022, 11:09:08 am »
The SON dynamos feature the venting of the internal air volume to the external world via a long spiral tube that is designed to stop droplets of water getting sucked through it, anyway the vent tube ensures no pressure difference across the bearings seals.

The failure mode of non vented dynamos (and potentially other hubs and sealed bearing BB systems) is that during a cold shock event the air pressure in the hub reduces rapidly and they draw air or whatever is around the bearings outer seal past the grease seals of the bearings into the hubs internal volume - bearing seals are not designed to be airtight.
When the cold shock event is submersion in water, the non vented hubs tend to draw water into their bearings. Very few designs use stainless steel bearings, so once the water is in the steel parts slowly develop corrosion and the bearing gets stiff/lumpy when parked up for a while then over time self destructs.
Another example of a cold shock event is taking a bike from a heated environment and riding it in cold weather.
Disc braked hubs run warmer so are more prone to cold shock events.

Re: Accidently submerged son28 dynamo hub and Rohloff hub...
« Reply #9 on: 14 January, 2022, 07:10:42 pm »
Thank you for the info and suggestions, I've taken the wheel off with the Son 28 hub and removed the QR axle and a drop of water came out - not quite the quantity I'd feared which is something. However, the bearings feel horrendously rough and the wheel barely spins on its axle when holding it in the hands.

I saw someone else mention that their Son had felt a bit rough too, I'm thinking I'll keep riding it until there is an option of getting another bike on the road to use. If anyone has any further thought it would be interesting to read these? Thanks

Kim

  • Timelord
Re: Accidently submerged son28 dynamo hub and Rohloff hub...
« Reply #10 on: 14 January, 2022, 07:20:38 pm »
It's normal for the magnets in a dynamo hub to make the axle hard to turn by hand, and give a strong 'cogging' sensation at low speed.

Re: Accidently submerged son28 dynamo hub and Rohloff hub...
« Reply #11 on: Yesterday at 11:52:24 am »
Hello,

Slightly embarrassing but I have to admit the sloshing water sound actually turned out to be inside the tyre rather than the hub - although very pleased to find that the hub is not a write off, and very grateful for all the info and support. They sound like both very durable hubs and great to hear that people have managed to get so many miles from them. It has been a good learning curve.

Thanks,

Re: Accidently submerged son28 dynamo hub and Rohloff hub...
« Reply #12 on: Yesterday at 12:59:48 pm »
I am a huge fan of the SON hub.  I bought my first in 2004 for my tourer and fairly quickly put a SON hub on mllePB's tourer.  Later I put them on both of our audax machines.  I regard them almost as a fit and forget hub and none has ever given us any issues.  I even bought a secondhand one because I have faith in their robustness and efficiency.

Not being a solo cyclist any more I have acquired a nice tandem for me to stoke.  The bike will get lighting and I will be replacing the front hub with a 36 hole SON taken from one of my other machines.  In fact, I could just use the front wheel from my tourer if I so wished but the rims wouldn't match.  🤔🙂

Re: Accidently submerged son28 dynamo hub and Rohloff hub...
« Reply #13 on: Yesterday at 01:30:29 pm »
Hello,

Slightly embarrassing but I have to admit the sloshing water sound actually turned out to be inside the tyre rather than the hub - although very pleased to find that the hub is not a write off, and very grateful for all the info and support. They sound like both very durable hubs and great to hear that people have managed to get so many miles from them. It has been a good learning curve.

Thanks,

On reading the OP I was going to suggest the sloshing was water in the rim.

A SON hub is very unlikely to ever be a write-off, if you manage to wear out the bearings or anything else fails you just send it back for an overhaul.

I'm a high-mileage, all-weather rider, though don't often go through floods deep enough to submerge the rims as my boots fill with water long before that depth. The first SON hub I got went back at 50,000 km for bearings and currently at 130,000 km shows no sign of play. The other one on the Brommie has done 10-20 km a day for the last 15+ years and is as good as new.
Quote from: tiermat
that's not science, it's semantics.