Folding Bikes - Internal gear maintenance

dear all,

yes, yes I know I should post this at the bike maintenance subforum.
but since mine is a folder, I preferably ask it here.

it's now the rainy season.
and in the part of the world where I live, the streets can be flooded.
can be as high as 1-2 feet.
since my folder is only a 14 inch wheel, you bet the shimano internal gear gets a dip, it hasn't taken any swimming lessons, so it gets drowned.
into dirty water, sure.
many say internal gear is maintenance free.
but I am not sure whether there is no dirt entering my hub.
is it safe to just leave it?
or shall I oil it? where? normal engine oil? SAE 40 ok? (I am in the tropics.)

thanks a lot...

I don't know the shimano hub gear, but if you are riding it submerged, or even if it just became submerged, I'd be surprised if water wasn't getting inside. If the hub is correctly greased, I suppose the machine parts would survive ok, but ridden under flood water, the seals would be almost bound to admit large amounts of water and fine dirt which would wear away at the small parts over time.

If it were mine, I'd be sure to remove the major components in a cluster after a dowsing and depending on what it was like in there, I'd service it. If it was just damp with plenty of grease on the moving parts, I'd just dry it off and next time not worry so much. Small amounts of water will probably just dry off in time in a hot climate. On the other hand, if it was soaked with soil contaminated water, or had any amount of water still in there, I'd be completely cleaning it with rags and a solvent and re-applying the correct grease (or whatever Shimano recommend).

One thing: the SA hubs are pretty sensitive about what you put inside them, so I expect the shimano are too since these things work in very similar ways. SA hubs need a very special light grease on the ring gear, planet pinion cage, and the clutch parts. It is VERY slippery and you must NOT apply ordinary grease to these parts or the extra drag will cause problems. These hubs use ordinary bearing grease only on the axle bearings at either side of the hub. Older versions were oil lubricated, but again, the oil had to be a light grade machine oil something like SAE10 or 10 weight is ok. Heavier and the pedals try to rotate when coasting in the top gear on a three speed. This can lead to chain derailment on bikes with sprung chain tensioners.

Some of us have experimented with oil lubrication on the new grease type hubs. It works, but the seals are not designed for it and if you are over generous, the oil soon comes out and runs all over the rear wheel. Some say the hub becomes more efficient if lubed this way, but you'd be lucky if you gained one percent by doing it.

If the wheel axle is submerged it will definitely take on water, no question. The hub will be toast unless you strip it and clean and re-lube. Try to avoid submerging at all costs.

i think i saw a bit on hubstripping.com about improving the seals on the nexus hubs.... ill try and find it for you

ok, HERE IT IS:
http://www.hubstripping.com/shimano-alfine/shimano-nexus-internal-gear-hub-maintenance.jpg
lots of info on this site!

Excellent link, but I doubt that will keep out water when the bike is run with the axle submerged as the poster described up top.

Still - a very useful hint for the rest of us if we have that hub.

:)

Even with my mountain bike I carry it across deeper stream crossings. Overhauling nearly [headset excepted] every bearing in my bike is less fun than it sounds.

Excellent link, but I doubt that will keep out water when the bike is run with the axle submerged as the poster described up top.

Still - a very useful hint for the rest of us if we have that hub.

:)

true, but if the OP is cracking the thing open anyways, he may as well give it a litle extra protection, no?
i have the nexus redband hub, and have heard the seals on this model are a bit better. still, i am not about to go swimming in filthy water with it (at least I hope not!!)