Regreasing Nexus 8 hub

Finlay Mackay wrote:
Is is

Quoted message said:

necessary to totally strip it down, or can I just take it to the point
of (for example) removing the shell, then pack it with grease and
reassemble?

pull the unit and grease everthing in sight. No further disassembly required

--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

Finlay Mackay said:

My Shimano Nexus 8 hub gear has started to make nasty grinding noises in
gears 6-8 (ie all of those which are gearing up the rotation of the
cog). I assume it needs re-greasing - I am a little worried it needs
this after only a year of fairly light use (1500-2000 miles), could it
be something else?

My own experiences have been with a Nexus 7. Mine started doing that
after water got in - once from being submerged as I rode through a
flood, the second time from snow packed around the hub. (Never had the
problem from heavy rain, though.)

Quoted message said:

I have the instructions at http://www.sheldonbrown.com/nexus8, have the
special grease on order and am happy I can strip down and rebuild the
hub (I doubt any local shops have much experience of these hubs anyway)
but I was wondering whether anyone had done this and had tips? Is is
necessary to totally strip it down, or can I just take it to the point
of (for example) removing the shell, then pack it with grease and
reassemble?

As Marten says, just extract the works and grease what you can see. I
used WD40 first to get rid of any water in there.

--
Andrew

M-gineering <[email hidden]> whizzed past me shouting

Quoted message said:

Finlay Mackay wrote:
Is is

Quoted message said:

necessary to totally strip it down, or can I just take it to the point
of (for example) removing the shell, then pack it with grease and
reassemble?

pull the unit and grease everthing in sight. No further disassembly required

Finlay - I'll have to do that before long - please could you post any
useful discoveries you make?

--
Sue ]🙁🙂

Finlay Mackay said:

My Shimano Nexus 8 hub gear has started to make nasty grinding noises in
gears 6-8 (ie all of those which are gearing up the rotation of the
cog). I assume it needs re-greasing - I am a little worried it needs
this after only a year of fairly light use (1500-2000 miles), could it
be something else?

I have the instructions at http://www.sheldonbrown.com/nexus8, have the
special grease on order and am happy I can strip down and rebuild the
hub (I doubt any local shops have much experience of these hubs anyway)
but I was wondering whether anyone had done this and had tips? Is is
necessary to totally strip it down, or can I just take it to the point
of (for example) removing the shell, then pack it with grease and
reassemble?

cheers,

Finlay

With mine, some seal had gone somewhere, and when it was opened up it
was like a relic from the Titanic. The bike shop asked me if I'd
recovered it from a lake :-) It had done just over 6k.

Anyway, the corrosion was so bad it had to be replaced, and the
replacement was carried out under shimano's 12 mth warranty. In the
meantime, I'd bought a Nexus 8 Deluxe from an ebay seller in Germany,
and found that to be a much better unit than the standard one.

I kept the replacement as a spare, but did another 8k on the deluxe
version one with no issues at all.

Naqerj said:

Finlay Mackay said:

My Shimano Nexus 8 hub gear has started to make nasty grinding noises in
gears 6-8 (ie all of those which are gearing up the rotation of the
cog). I assume it needs re-greasing - I am a little worried it needs
this after only a year of fairly light use (1500-2000 miles), could it
be something else?

My own experiences have been with a Nexus 7. Mine started doing that
after water got in - once from being submerged as I rode through a
flood, the second time from snow packed around the hub. (Never had the
problem from heavy rain, though.)

There has been a lot of rain here this winter and several times bits of
my commute have been flooded - junctions/underpasses etc with a few
inches of water - I'll bet riding through those has done it, along with 2
weeks off at xmas to give the corrosion a chance to get going. And the
warranty has just run out too.

cheers

Finlay

Finlay Mackay said:

Naqerj said:

Finlay Mackay said:

My Shimano Nexus 8 hub gear has started to make nasty grinding noises in
gears 6-8

Quoted message said:

And the warranty has just run out too.

You might care to look up your rights as an EU consumer then 😉
--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

M-gineering said:

Finlay Mackay said:

Naqerj said:

Finlay Mackay wrote:
> My Shimano Nexus 8 hub gear has started to make nasty grinding noises in
> gears 6-8

Quoted message said:

And the warranty has just run out too.

You might care to look up your rights as an EU consumer then 😉

I'm not sure how easy it would be to cliam that any damage which may
have occurred is not the result of normal wear and tear. In any case,
this morning as I crossed some rough cobbles the hub seized up in 5th
(direct drive) and I thought all was lost. But after a bit of shifting
up and down, backpedalling etc it started working again and the noise in
the higher gears had gone. I'm more worried now, if anything, so I'm
going to take a look inside asap in case something is badly wrong, eg
there's a broken bit rattling round inside.

cheers,

Finlay

Finlay Mackay said:

M-gineering said:

Finlay Mackay said:

On 2007-01-28, Naqerj <[email hidden]> wrote:
> Finlay Mackay wrote:
>> My Shimano Nexus 8 hub gear has started to make nasty grinding noises in
>> gears 6-8

Quoted message said:

And the warranty has just run out too.

You might care to look up your rights as an EU consumer then 😉

I'm not sure how easy it would be to cliam that any damage which may
have occurred is not the result of normal wear and tear. In any case,
this morning as I crossed some rough cobbles the hub seized up in 5th
(direct drive) and I thought all was lost. But after a bit of shifting
up and down, backpedalling etc it started working again and the noise in
the higher gears had gone. I'm more worried now, if anything, so I'm
going to take a look inside asap in case something is badly wrong, eg
there's a broken bit rattling round inside.

As an aside, I have a 4-speed Nexus ans was thinking it'd be OK on a hack
bike (Northants, so no real hills), but I've broken 3 AW3s and this thread
has made me nervous about Nexi.
If they're as easy to break as SAs, does any one want this one - free apart
from P&P?

--
Peter.
If you can do it today, you didn't put off enough yesterday.

Peter said:

If they're as easy to break as SAs, does any one want this one - free
apart from P&P?

Check your email :-)

Tom
--
Return address is dead. Real address is at
http://www.happy-penguin.info/address.jpg

Finlay Mackay said:

My Shimano Nexus 8 hub gear has started to make nasty grinding noises in
gears 6-8 (ie all of those which are gearing up the rotation of the
cog). I assume it needs re-greasing - I am a little worried it needs
this after only a year of fairly light use (1500-2000 miles), could it
be something else?

I have the instructions at http://www.sheldonbrown.com/nexus8, have the
special grease on order and am happy I can strip down and rebuild the
hub (I doubt any local shops have much experience of these hubs anyway)
but I was wondering whether anyone had done this and had tips? Is is
necessary to totally strip it down, or can I just take it to the point
of (for example) removing the shell, then pack it with grease and
reassemble?

Prompted by this thread and the fact that mine had just started to make
a noise when freewheeling. Either that or I have only noticed it because
of this thread. I have just re greased mine.

I printed off the relevant pages from Sheldon's site [1] as well as the
assembly instructions from Shimano [2]. Why? well the manual Sheldon has
starts off with a hub with the drive sprocket already removed.

Once the wheel was off the bike I started going through the assembly
instructions [2] in reverse. Things that I found tricky/different were:
o Removing the snap ring from the sprocket assembly, but persistence
paid off.
o I did not have a right hand dust cap B fitted which I would have
expected as my sprocket is 21T.
o I had to remove the large right hand dust cap prior to removing the
hub shell
o Heed the warning about removing the stop ring. I did not lose mine,
but only because I had it smothered.
o I could not identify the ring gear stop ring for removal, so I didn't.
o I did not disassemble the axle unit any further than stage 10, and
that was probably a step more than necessary.
o The pictures all show a nice clean unit, mine was not.
o Reassembly started at step 11 of the assembly instructions, applying
grease liberally at the indicated locations and turning teeth etc round
to work it in [4].
o Getting the stop ring on was a hassle until I stopped trying and just
eased it into place with a mole grip.
o The snap ring again presented a bit of a problem and did not want to
go back on at first, but I managed to persuade it.

It took me about 2.5 hours from walking out the front door to walking
back in leaving the bike ready to ride having also checked tyre
pressures and reset the seat hight after having to move it to use the
stand. I was expecting it to take longer, but found the job quite easy.

As an aside, when I was putting everything back together I checked the
chain line on my bike. Prompted by either something said here or
something I had read on Sheldon's site. Just looking from the back wheel
along the sprocket, the chain ring is not in line. I can't shift the
sprocket about with spacers as the hub gears do not allow for that so I
need to shift the chain ring out a bit. I assume that means I need to
replace the BB with one that has a longer (for want of a better word)
RHS taper.

[1] http://sheldonbrown.com/nexus8/
[2] http://preview.tinyurl.com/2ryegk opens up [3]
[3]
http://cycle.shimano-eu.com/media/cycling/techdocs/en/bikecomponents/SG/SI-34R0D_v1_m56577569830592938.pdf
[4] I did not use Shimano's recommended grease, rather a Teflon based
one that I picked up at a LBS for general greasing. This stuff is
supposed to handle high temperatures so I think it should be OK. If it
all suddenly falls apart ...

--
Don Whybrow

Sequi Bonum Non Time

If you're happy and you know it, clunk your chains.

Don Whybrow said:

Prompted by this thread and the fact that mine had just started to make
a noise when freewheeling. Either that or I have only noticed it because
of this thread. I have just re greased mine.

Well, as the actress said to the bishop, a bit of lubrication makes a
world of difference.

--
Don Whybrow

Sequi Bonum Non Time

"The POP3 server service depends on the SMTP server service,
which failed to start because of the following error: The
operation completed successfully." (Windows NT Server v3.51)

Most people seem to use their nexus hub gears without servicing them
until they fail. When they investigate the hub they tend to find that
the grease is no longer there. Would anyone have any comments on the
wisdom of regreasing the hub as a form of preventative maintenance,
and if so, at what sort of mileage would this be recommended?

Thanks
Ray

raisethe said:

Most people seem to use their nexus hub gears without servicing them
until they fail. When they investigate the hub they tend to find that
the grease is no longer there. Would anyone have any comments on the
wisdom of regreasing the hub as a form of preventative maintenance,
and if so, at what sort of mileage would this be recommended?

From the Shimano website at http://preview.tinyurl.com/3xkzu9 [1]:

"Shimano recommends to perform maintenance on an internal geared hub
every 5000km's or every 2 years. When the bike is used in severe
(wheater) conditions, it may be necessary to shorten this interval."

[1] Resolves to
http://cycle.shimano-eu.com/publish/content/cycle/seh/nl/en/technical_service/faq_s/city_and_comfort_bike/do_i_have_to_perfom.html

--
Don Whybrow

Sequi Bonum Non Time

Give your child mental blocks for Christmas.

Don Whybrow said:

"Shimano recommends to perform maintenance on an internal geared hub
every 5000km's or every 2 years.

So every 2 months, do they mean?
--
Peter.
If you can do it today, you didn't put off enough yesterday.

PeterC said:

Don Whybrow said:

"Shimano recommends to perform maintenance on an internal geared hub
every 5000km's or every 2 years.

So every 2 months, do they mean?

Well, I have only had mine a year (~3000-4000km) and it has benefited
from a strip down and re-grease. I am not sure I would have waited for
the 2 years given the noises I was getting. Neither would I have used
the dipping oil. It may look good doing it with a nice shiny new hub,
but with old grease in the gears it would need a method of filtering out
the gunk after each use. It also seems a bit light to last 2 years with.
It would need backing up with grease anyway.

--
Don Whybrow

Sequi Bonum Non Time

They used dogs. They used probes. They used cardio plate
crossoffs. They used teepers. They used bribery. They used
stick tites. They used intimidation. They used torment. They
used torture. They used finks. They used cops. They used
search and seizure. They used fallaron. They used betterment
incentives. They used finger prints. They used the bertillion
system. They used cunning. They used guile. They used
treachery. They used Raoul-Mitgong but he wasn't much help.
They used applied physics. They used techniques of criminology.
And what the hell, they caught him. (Harlan Ellison, "Repent,
Harlequin, said the Tick-Tock Man"😉

Don Whybrow said:

PeterC said:

On Sat, 03 Feb 2007 23:36:19 +0000, Don Whybrow wrote:

Quoted message said:

Quoted message said:

"Shimano recommends to perform maintenance on an internal geared hub
every 5000km's or every 2 years.

Well, I have only had mine a year (~3000-4000km) and it has benefited
from a strip down and re-grease. I am not sure I would have waited for
the 2 years given the noises I was getting. Neither would I have used
the dipping oil. It may look good doing it with a nice shiny new hub,
but with old grease in the gears it would need a method of filtering out
the gunk after each use. It also seems a bit light to last 2 years with.
It would need backing up with grease anyway.

--
Don Whybrow

Thanks Don, I had somehow missed that page on the shimano site. The
5,000km interval would mean twice a year for me to strip it down and
relube.

Is there any reason to suppose that heavy grease is preferable to oil
in this application, after all, motor vehicle gearboxes run in oil
quite happily. The only reason I can think of is that the hub isn't
oil tight so it may leak away.

I can't tell from the web page but is the intention to provide a
coating of oil to the internal parts or to actually have a quantity of
oil sloshing about in the hub? (Excuse my ignorance, but I've never
had a pushbike with a gearbox before).

raisethe said:

Is there any reason to suppose that heavy grease is preferable to oil
in this application, after all, motor vehicle gearboxes run in oil
quite happily. The only reason I can think of is that the hub isn't
oil tight so it may leak away.

I can't tell from the web page but is the intention to provide a
coating of oil to the internal parts or to actually have a quantity of
oil sloshing about in the hub? (Excuse my ignorance, but I've never
had a pushbike with a gearbox before).

Here we hit the limits of my ignorance as well!

ISTR that the Rohloff has an oil bath, so I presume that it has oil
tight joints. From what I can tell of the Nexus, it does not have oil
tight joints, although I will not be offended if I am proven wrong. My
interpretation is that the dipping oil would give a coating to all the
parts, but that this would dissipate after a while. Grease would hold
the lubricants where they are needed. Motor vehicle gearboxes are even
more a mystery to me, but I would have thought that the comparison fails
as they are not part of the axle of the driving wheel and do not rotate
themselves. Do they not also have a sump and a mechanism for circulating
and cleaning the oil?.

--
Don Whybrow

Sequi Bonum Non Time

"No man's life, liberty, or property is safe while the
legislature is in session." (Judge Gideon J. Tucker, 1866.)

Do they not also have a sump and a mechanism for circulating

Quoted message said:

and cleaning the oil?.

--
Don Whybrow

True. However, the oil tends to only deteriorate because of engine
generated heat. The gunge that people are reporting in Nexus hubs
would probably write off a motor vehicle engine. It would certainly
appear that the Nexus hubs are not properly sealed which is strange
given that they are designed for use in bad weather. In fact, if the
components are circulating whilst enclosed in a grungy paste they are
likely to last less longer than a derailleur system.

Perhaps I will lubricate the hub more frequently than the recommended
5,000km - I'll see what its like the first time I go in there.

raisethe said:

True. However, the oil tends to only deteriorate because of engine
generated heat. The gunge that people are reporting in Nexus hubs
would probably write off a motor vehicle engine. It would certainly
appear that the Nexus hubs are not properly sealed which is strange
given that they are designed for use in bad weather. In fact, if the
components are circulating whilst enclosed in a grungy paste they are
likely to last less longer than a derailleur system.

OK mine was not clean, but I would not have expected it to be. What was
there did not seem to me to be the residue of ground up components or
paste. I do not know if grease breaks down after a period of use, but it
would seem reasonable to me. I do not think that the reported gunge it
anything other than spent grease. All you are doing by re-greasing the
hub is replacing this used up stuff. I do not think that it is valid to
compare the performance of lubricants in a bike hub gear to those in an
engine or vehicle gearbox. The conditions are completely different.

Quoted message said:

Perhaps I will lubricate the hub more frequently than the recommended
5,000km - I'll see what its like the first time I go in there.

Simple rule of thumb, if it sounds rough, slap some grease in, otherwise
why bother.

--
Don Whybrow

Sequi Bonum Non Time

People must not do things for fun. We are not here for fun.
There is no reference to fun in any Act of Parliament.