Sealed Hubs

Duncan Smith said:

It's been about 10 years since I last bought a new bike and I can't
remember whether that had sealed hubs or not. I've had a few older
generation bikes without sealed hubs and have gotten into the habit of
holding the wheel with one hand and giving it a spin on the horiz axis,
whilst squeezing some 'cross country finish line' oil around the hub
before placing the wheel back on the floor to let the oil seep into the
hub.

I (perhaps incorrectly) kept this practice up with my new bike, and
find that the front wheel barely spins when given a push now - never
mind glides, and feels extremely gritty. After only a couple of
months.

Probably harm as sealed bearings are really not meant to be serviced at all
- when they're worn out you must pop them out and replace them if possible -
try and get the service instructions for your hub if it is a name brand like
Shimano.

Additionally and probably more importantly, Cross Country is a chain lube
and even hubs that can be serviced usually require grease so all the oil
will do is wash what's there out of the bearings and probably flush crud
that's on the seals into them.

http://www.parktool.com/repair/readhowto.asp?id=105

details the correct procedure for servicing cup n'cone hubs.

Regards,

-david

Duncan Smith said:

It's been about 10 years since I last bought a new bike and I can't
remember whether that had sealed hubs or not. I've had a few older
generation bikes without sealed hubs and have gotten into the habit of
holding the wheel with one hand and giving it a spin on the horiz
axis, whilst squeezing some 'cross country finish line' oil around
the hub before placing the wheel back on the floor to let the oil
seep into the hub.

I (perhaps incorrectly) kept this practice up with my new bike, and
find that the front wheel barely spins when given a push now - never
mind glides, and feels extremely gritty. After only a couple of
months.

Now, it could be, that like a number of other entry level components
that came with the bike, it's just rubbish and needs replacing with
something better. Or am I doing bad things to the seals and should
leave them well alone?

Hub bearings are usually packed with grease. Grease contains oil and lasts
a long time, so the hubs don't need oiling.

The seals themselves are probably still OK, but you've been flushing grit
in, and thinning the grease inside, if there's any left.

You normally should either leave the hubs alone or service properly (if they
are a serviceable type) - by taking apart, cleaning and regreasing.

Hopefully your hubs are not wrecked and a service will sort them out. Do
you know the make and model?

By the way, "sealed hub" doesn't really mean anything because nearly all
hubs have some sort of seals, and there are many different sorts of seals.

~PB

On 2007-01-06, David Nutter <[email hidden]> wrote:

*snip*

Quoted message said:

Probably harm as sealed bearings are really not meant to be serviced at all
- when they're worn out you must pop them out and replace them if possible -
try and get the service instructions for your hub if it is a name brand like
Shimano.

In light of Pete's post here I was perhaps unclear - by "sealed hubs" I took
you to mean "hubs with sealed cartridge bearings" rather than "cup and cone hubs with a
dust seal". In the former the bearings are not usually servicable and in
some cases the whole hub must be discarded if they fail. In the latter,
there is just an extra thingy between the cone and the locknut.

Regards,

-david

In article <[email hidden]>, Duncan
Smith
[email hidden] says...

Quoted message said:

It's been about 10 years since I last bought a new bike and I can't
remember whether that had sealed hubs or not. I've had a few older
generation bikes without sealed hubs and have gotten into the habit of
holding the wheel with one hand and giving it a spin on the horiz axis,
whilst squeezing some 'cross country finish line' oil around the hub
before placing the wheel back on the floor to let the oil seep into the
hub.

I (perhaps incorrectly) kept this practice up with my new bike, and
find that the front wheel barely spins when given a push now - never
mind glides, and feels extremely gritty. After only a couple of
months.

Now, it could be, that like a number of other entry level components
that came with the bike, it's just rubbish and needs replacing with
something better. Or am I doing bad things to the seals and should
leave them well alone?

Hubs bearings are packed with grease, oiling them washes grease out and
grit in - the only way to relubricate most hubs is to strip them down,
clean out the old grase and replace with new. Finish Line Cross Country
is chain lube, don't use it for anything else (except maybe cables).
"Sealed" hubs could be anything from high quality cartridge bearings to
cheap'n'nasty CCB with a bit of plastic stuck on the outside. Whichever
yours are (and the latter sounds likely) they need to be stripped,
cleaned and regreased.