shimano nexus 8 hub gear



R

raisethe

Guest
A few questions:

Is there any link available which explains in detail how the nexus hub
gear works? If not, how about hub gears in general, as I presume it is
not a million miles from the old Sturmey Archers?

I have seen the manual on sheldon's website for stripping down one of
these hub gears. Is there any place where this manual can be purchased
or otherwise downloaded? The manual says it is volume one. What is
volume two?

The shimano website appears to have nothing more than a fully detailed
diagram but no service instructions - I can't be 100% sure because it
keeps seizing up my computer when I go on there. Is there any other
documentation available on these gears from Shimano?

The diagram and the manual on sheldon's page recommends the use of
shimano grease and special tools, and part numbers are provided. Can
anyone recommend an internet supplier that is used to ordering
specific and relatively obscure parts off shimano - my lbs's are a
waste of time - do you think wiggle would be up to it?

Apologies for all the questions, but the hub will be due for its first
5,000 km strip and grease in a few weeks, so I want to get as much
information together as I can before I go in there, and try to limit
downtime.

Many thanks for any help.

Ray
 
M

Mark McNeill

Guest
Response to raisethe:
> I have seen the manual on sheldon's website for stripping down one of
> these hub gears. Is there any place where this manual can be purchased
> or otherwise downloaded? The manual says it is volume one. What is
> volume two?


Putting it back together. This manual is unavailable. ;-)


--
Mark, UK
"The origin of all science is the desire to know causes, and the origin
of all false science and imposture is the desire to accept false causes
rather than none, or, which is the same thing, in the unwillingness to
acknowledge our own ignorance."
 
On May 17, 4:59 pm, Mark McNeill <[email protected]> wrote:
> Response to raisethe:
>
> > I have seen the manual on sheldon's website for stripping down one of
> > these hub gears. Is there any place where this manual can be purchased
> > or otherwise downloaded? The manual says it is volume one. What is
> > volume two?

>
> Putting it back together. This manual is unavailable. ;-)


Some time ago, I found a manual with diagrams on line for the 4 speed
Nexus hub. It was all in German. The on-line translator couldn't
handle technological terms so it was fun to read the output.
 
A

A Muzi

Guest
> Response to raisethe:
>> I have seen the manual on sheldon's website for stripping down one of
>> these hub gears. Is there any place where this manual can be purchased
>> or otherwise downloaded? The manual says it is volume one. What is
>> volume two?


Mark McNeill wrote:
> Putting it back together. This manual is unavailable. ;-)


Not to worry. As the British car manuals say, "assembly is the reverse
of disassembly".

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
 
O

Ozark Bicycle

Guest
On May 17, 10:26 pm, A Muzi <[email protected]> wrote:
> > Response to raisethe:
> >> I have seen the manual on sheldon's website for stripping down one of
> >> these hub gears. Is there any place where this manual can be purchased
> >> or otherwise downloaded? The manual says it is volume one. What is
> >> volume two?

> Mark McNeill wrote:
> > Putting it back together. This manual is unavailable. ;-)

>
> Not to worry. As the British car manuals say, "assembly is the reverse
> of disassembly".
>


Or "installation is the reverse of removal".....eeekkkkkk!

I will never buy another Brit car
I will never buy another Brit car
I will never buy another Brit car

(must keep repeating this to self until I am not longer tempted by the
very nice MGA I saw for sale.........)
 
K

Kerry Montgomery

Guest
"A Muzi" <[email protected]> wrote in message
news:[email protected]
>> Response to raisethe:
>>> I have seen the manual on sheldon's website for stripping down one of
>>> these hub gears. Is there any place where this manual can be purchased
>>> or otherwise downloaded? The manual says it is volume one. What is
>>> volume two?

>
> Mark McNeill wrote:
>> Putting it back together. This manual is unavailable. ;-)

>
> Not to worry. As the British car manuals say, "assembly is the reverse of
> disassembly".
>
> --
> Andrew Muzi
> www.yellowjersey.org
> Open every day since 1 April, 1971

With no offense to the OP, saw a show on the military channel about tanks -
one of the segments showed an enlisted man who'd just removed one link of a
track, and asked his commander (Sergeant?) how to put in the replacement.
The commander said, "You need a special tool for that, common sense. You
may not have been issued that yet."
Kerry
 
R

Ryan Cousineau

Guest
In article <[email protected]>,
A Muzi <[email protected]> wrote:

> > Response to raisethe:
> >> I have seen the manual on sheldon's website for stripping down one of
> >> these hub gears. Is there any place where this manual can be purchased
> >> or otherwise downloaded? The manual says it is volume one. What is
> >> volume two?

>
> Mark McNeill wrote:
> > Putting it back together. This manual is unavailable. ;-)

>
> Not to worry. As the British car manuals say, "assembly is the reverse
> of disassembly".


You're doing well if that's what it says. My father's 1958 AJS user's
manual described the bus routes that would take you to the factory.

I am not making this up,

--
Ryan Cousineau [email protected] http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos
 
S

Simon Brooke

Guest
in message <[email protected]>, raisethe
('[email protected]') wrote:

> A few questions:
>
> Is there any link available which explains in detail how the nexus hub
> gear works? If not, how about hub gears in general, as I presume it is
> not a million miles from the old Sturmey Archers?


It's not a million miles from. They're all epicyclics. Any single epicyclic
train gives three potential speeds: cage locked to shaft, shaft driven,
cage driven. Hubs with more than three speeds have more than one epicyclic
train. A hub with two trains will have five potential gears, because
the 'cage locked to shaft' gear is the same for both trains; a hub with
three trains, seven gears. I don't personally understand how eight gear
hubs work...

General explanation here:
http://en.wikipedia.org/wiki/Epicyclic_gearing

What's tricky - and gets trickier as the number of trains goes up - is how
you switch between the different gears.

--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

I'm fed up with Life 1.0. I never liked it much and now it's getting
me down. I think I'll upgrade to MSLife 97 -- you know, the one that
comes in a flash new box and within weeks you're crawling with bugs.
 
G

GeoffC

Guest
raisethe <[email protected]> wrote:
> A few questions:
>
> Is there any link available which explains in detail how the nexus hub
> gear works? If not, how about hub gears in general, as I presume it is
> not a million miles from the old Sturmey Archers?
>
> I have seen the manual on sheldon's website for stripping down one of
> these hub gears. Is there any place where this manual can be purchased
> or otherwise downloaded?


You could try this link

http://www.bruegelmann-shop.de/shimano/TN_GE/TN_10_EN.PDF

HTH

--

Geoff
 
D

Don Whybrow

Guest
raisethe wrote:
> A few questions:
>
> Is there any link available which explains in detail how the nexus hub
> gear works? If not, how about hub gears in general, as I presume it is
> not a million miles from the old Sturmey Archers?
>
> I have seen the manual on sheldon's website for stripping down one of
> these hub gears. Is there any place where this manual can be purchased
> or otherwise downloaded? The manual says it is volume one. What is
> volume two?
>
> The shimano website appears to have nothing more than a fully detailed
> diagram but no service instructions - I can't be 100% sure because it
> keeps seizing up my computer when I go on there. Is there any other
> documentation available on these gears from Shimano?
>
> The diagram and the manual on sheldon's page recommends the use of
> shimano grease and special tools, and part numbers are provided. Can
> anyone recommend an internet supplier that is used to ordering
> specific and relatively obscure parts off shimano - my lbs's are a
> waste of time - do you think wiggle would be up to it?
>
> Apologies for all the questions, but the hub will be due for its first
> 5,000 km strip and grease in a few weeks, so I want to get as much
> information together as I can before I go in there, and try to limit
> downtime.


First you need to get the thing off the bike, remove the cassette joint
and sprocket.
Follow this in reverse order:
<http://cycle.shimano-eu.com/media/techdocs/content/cycle/SI/Nexus/SG-8R20/34R0D-SG-8R20-EN_v1_m56577569830600211.pdf>

The sprocket removal can be a bit tricky as you need to open out the
snap ring. I have done this using a couple of flat bladed screwdrivers
and a lot of swearing. There may be a tool out there for this.

To strip and re-build the hub, I have followed the manual on Sheldon's
site at <http://sheldonbrown.com/nexus8/index.htm> but the furthest I
have disassembled one was to step 10 on
<http://sheldonbrown.com/nexus8/pages/15.htm>.
I printed the manual directly from Sheldon's site

If you are looking to just clean out the gunk, you could use the Shimano
cleaning system,
<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>,
but it seems a bit wasteful to me.

As far as the grease is concerned, I used whatever was in my gun at the
time. The last time I had the innards out, I just pumped it into every
available place I could see without taking it all to pieces.


--
Don Whybrow

Sequi Bonum Non Time

"This is all very interesting, and I daresay you already see me
frothing at the mouth in a fit; but no, I am not; I am just
winking happy thoughts into a little tiddle cup." (Nabokov,
Lolita)
 
R

raisethe

Guest
On 18 May, 20:58, Don Whybrow <[email protected]> wrote:
> raisethe wrote:
> > A few questions:

>
> > Is there any link available which explains in detail how the nexus hub
> > gear works? If not, how about hub gears in general, as I presume it is
> > not a million miles from the old Sturmey Archers?

>
> > I have seen the manual on sheldon's website for stripping down one of
> > these hub gears. Is there any place where this manual can be purchased
> > or otherwise downloaded? The manual says it is volume one. What is
> > volume two?

>
> > The shimano website appears to have nothing more than a fully detailed
> > diagram but no service instructions - I can't be 100% sure because it
> > keeps seizing up my computer when I go on there. Is there any other
> > documentation available on these gears from Shimano?

>
> > The diagram and the manual on sheldon's page recommends the use of
> > shimano grease and special tools, and part numbers are provided. Can
> > anyone recommend an internet supplier that is used to ordering
> > specific and relatively obscure parts off shimano - my lbs's are a
> > waste of time - do you think wiggle would be up to it?

>
> > Apologies for all the questions, but the hub will be due for its first
> > 5,000 km strip and grease in a few weeks, so I want to get as much
> > information together as I can before I go in there, and try to limit
> > downtime.

>
> First you need to get the thing off the bike, remove the cassette joint
> and sprocket.
> Follow this in reverse order:
> <http://cycle.shimano-eu.com/media/techdocs/content/cycle/SI/Nexus/SG-...>
>
> The sprocket removal can be a bit tricky as you need to open out the
> snap ring. I have done this using a couple of flat bladed screwdrivers
> and a lot of swearing. There may be a tool out there for this.
>
> To strip and re-build the hub, I have followed the manual on Sheldon's
> site at <http://sheldonbrown.com/nexus8/index.htm> but the furthest I
> have disassembled one was to step 10 on
> <http://sheldonbrown.com/nexus8/pages/15.htm>.
> I printed the manual directly from Sheldon's site
>
> If you are looking to just clean out the gunk, you could use the Shimano
> cleaning system,
> <http://cycle.shimano-eu.com/publish/content/cycle/seh/nl/en/technical...>,
> but it seems a bit wasteful to me.
>
> As far as the grease is concerned, I used whatever was in my gun at the
> time. The last time I had the innards out, I just pumped it into every
> available place I could see without taking it all to pieces.
>
> --
> Don Whybrow
>
> Sequi Bonum Non Time
>
> "This is all very interesting, and I daresay you already see me
> frothing at the mouth in a fit; but no, I am not; I am just
> winking happy thoughts into a little tiddle cup." (Nabokov,
> Lolita)- Hide quoted text -
>
> - Show quoted text -


Thanks for those links. When you greased it, were you able to access
the ball races without stripping it down? That seems to be the main
area where the grease will come in handy.

How much grease do you recommend putting into the roller brake - a
squirt from the gun or just a very small quantity? (Mine is working
fine at the moment, no scraping noises).

Thanks
Ray
 
M

Martin Dann

Guest
A Muzi wrote:

> Not to worry. As the British car manuals say, "assembly is the reverse
> of disassembly".


Does one use a different hammer to reassemble it, or does the
disassemble hammer do both jobs?
 
D

Don Whybrow

Guest
raisethe wrote:
> On 18 May, 20:58, Don Whybrow <[email protected]> wrote:
>>
>> To strip and re-build the hub, I have followed the manual on Sheldon's
>> site at <http://sheldonbrown.com/nexus8/index.htm> but the furthest I
>> have disassembled one was to step 10 on
>> <http://sheldonbrown.com/nexus8/pages/15.htm>.
>> I printed the manual directly from Sheldon's site
>>


....

>
> Thanks for those links. When you greased it, were you able to access
> the ball races without stripping it down? That seems to be the main
> area where the grease will come in handy.


The first ball race you come across you remove in order to take the gear
assembly out of the shell, see step 4.

The next one can be seen in step 6 when you remove the RH dust cap. but
does not get removed until step 10.

I have not gone any further than that to get to the one in step 18

The first 2 are easy to reach the last more difficult.

When I greased up the insides without disassembly I tried to get as much
as possible into the body of the system, primarily through the 3 exposed
gears on the LH side of the assembly. I also greased up the ball races
and anything that looked as though it would move.

> How much grease do you recommend putting into the roller brake - a
> squirt from the gun or just a very small quantity? (Mine is working
> fine at the moment, no scraping noises).


When I have done this, I have put a squirt in at a time and then spun
the wheel and applied the brake to get it distributed. Then repeated
until the grease starts to come out somewhere. Again I have not used the
Shimano specific grease.

If you want to see the principle of how they work:
<http://cycle.shimano-eu.com/publish/content/cycle/seh/nl/en/technical_service/faq_s/city_and_comfort_bike/how_does_a_roller.html>


--
Don Whybrow

Sequi Bonum Non Time

'Tis an ill wind that blows no minds.
 
R

raisethe

Guest
On 19 May, 00:30, Don Whybrow <[email protected]> wrote:
> raisethe wrote:
> > On 18 May, 20:58, Don Whybrow <[email protected]> wrote:

>
> >> To strip and re-build the hub, I have followed the manual on Sheldon's
> >> site at <http://sheldonbrown.com/nexus8/index.htm> but the furthest I
> >> have disassembled one was to step 10 on
> >> <http://sheldonbrown.com/nexus8/pages/15.htm>.
> >> I printed the manual directly from Sheldon's site

>
> ...
>
>
>
> > Thanks for those links. When you greased it, were you able to access
> > the ball races without stripping it down? That seems to be the main
> > area where the grease will come in handy.

>
> The first ball race you come across you remove in order to take the gear
> assembly out of the shell, see step 4.
>
> The next one can be seen in step 6 when you remove the RH dust cap. but
> does not get removed until step 10.
>
> I have not gone any further than that to get to the one in step 18
>
> The first 2 are easy to reach the last more difficult.
>
> When I greased up the insides without disassembly I tried to get as much
> as possible into the body of the system, primarily through the 3 exposed
> gears on the LH side of the assembly. I also greased up the ball races
> and anything that looked as though it would move.
>
> > How much grease do you recommend putting into the roller brake - a
> > squirt from the gun or just a very small quantity? (Mine is working
> > fine at the moment, no scraping noises).

>
> When I have done this, I have put a squirt in at a time and then spun
> the wheel and applied the brake to get it distributed. Then repeated
> until the grease starts to come out somewhere. Again I have not used the
> Shimano specific grease.
>
> If you want to see the principle of how they work:
> <http://cycle.shimano-eu.com/publish/content/cycle/seh/nl/en/technical...>
>
> --
> Don Whybrow
>
> Sequi Bonum Non Time
>
> 'Tis an ill wind that blows no minds.


All points noted. Thank you for the advice.
 
D

DougC

Guest
raisethe wrote:
> A few questions:
>
> Is there any link available which explains in detail how the nexus hub
> gear works? If not, how about hub gears in general, as I presume it is
> not a million miles from the old Sturmey Archers?
>


What exactly are the improvements of the 8-speed over the 7-speed, and
is the 8- available with a coaster brake? Durability, gearing range or
both? I am pondering buying a bicycle that has the single, 3- and
7-speed coaster-brake Shimanos as an option. The 3-speed is priced $80
over the cost of a single, the 7-speed is $220.

This is to be a general utility bike, and I'm not much interested in the
idea of hand-operated brakes at all.

I haven't rode a geared hub in a long time and then it was only
3-speeds. I've got a 3-speed bike on order but from the Sheldon page,
there would seem to be significant improvements of the 7- over the 3-.

----

Also--what usually happens when a geared hub fails?
Does just one speed fail, or a subset of speeds, or does the whole thing
go to ****? Does the wheel lock up or spin free?.....

I'm a pretty large guy and can crank quite hard, if only for short
periods. (I used to ALWAYS break drive-side spokes on new MTB's I
bought, until I had a bulletproof rear wheel built)
~
 
I

Ian Smith

Guest
["Followup-To:" header set to uk.rec.cycling.]
On Sun, 20 May 2007 13:33:47 -0500, DougC <[email protected]> wrote:
>
> What exactly are the improvements of the 8-speed over the 7-speed,


Slightly wider range. Slightly closer steps.

regards, Ian SMith
--
|\ /| no .sig
|o o|
|/ \|
 
B

bob prohaska's usenet account

Guest
In rec.bicycles.tech DougC <[email protected]> wrote:
>
> I'm a pretty large guy and can crank quite hard, if only for short
> periods. (I used to ALWAYS break drive-side spokes on new MTB's I
> bought, until I had a bulletproof rear wheel built)
> ~

I'm a smallish rider, recently obliged by a broken foot to ride
my dad's Nexus-8 equipped Breezer. It's a wonderful bike, easy
to ride and immensely convenient, but the hub does not seem up to a
very strong rider. The gearing will "slip", after a shift, not changing
gears but losing engagement and then recovering. The sound it
makes is not reassuring and is unlikely to be improved by more
muscle on the pedals. The problem was reduced by a visit to the
dealer, but not eliminated.

My impression is that it's a wonderful hub for considerate riders.
Mashers need not apply. The gearing approaches 4:1, far better than
the old 3-speeds. Less than a change-cog, but neater by far and
sufficient for medium hills and stiff headwinds.

I'd say "buy one, but be gentle".

bob prohaska
 
B

Bill

Guest
bob prohaska's usenet account wrote:
> In rec.bicycles.tech DougC <[email protected]> wrote:
>> I'm a pretty large guy and can crank quite hard, if only for short
>> periods. (I used to ALWAYS break drive-side spokes on new MTB's I
>> bought, until I had a bulletproof rear wheel built)
>> ~

> I'm a smallish rider, recently obliged by a broken foot to ride
> my dad's Nexus-8 equipped Breezer. It's a wonderful bike, easy
> to ride and immensely convenient, but the hub does not seem up to a
> very strong rider. The gearing will "slip", after a shift, not changing
> gears but losing engagement and then recovering. The sound it
> makes is not reassuring and is unlikely to be improved by more
> muscle on the pedals. The problem was reduced by a visit to the
> dealer, but not eliminated.
>
> My impression is that it's a wonderful hub for considerate riders.
> Mashers need not apply. The gearing approaches 4:1, far better than
> the old 3-speeds. Less than a change-cog, but neater by far and
> sufficient for medium hills and stiff headwinds.
>
> I'd say "buy one, but be gentle".
>
> bob prohaska
>
>
>

I may be incorrect, but I think the basic 3 speeds used a planetary gear
set, first gear being in reduction mode, second being 1:1, and third
being the overdrive mode. 2 planetary gears might be all that is needed
for an 8 speed but the gears would be smaller than a 3 speed.
That is my best guess since that is what is done in car automatic
transmissions with hydraulic shifting.
I think the "Be gentle" would apply, and don't try to shift under full
leg power.
Bill Baka
Accuracy not guaranteed.
 
M

Mark Thompson

Guest
> The gearing will "slip", after a shift, not changing
> gears but losing engagement and then recovering. The sound it
> makes is not reassuring and is unlikely to be improved by more
> muscle on the pedals. The problem was reduced by a visit to the
> dealer, but not eliminated.


Never shift under load - no bicycle gears are made to be changed whilst
putting lots of power through the chain. Slacken off briefly until the
change is made and then stomp on the power. If you think it's the gears,
get a mechanic to do a test ride - if it's shifting fine the problem is you
abusing the poor bike ;)
 
R

Roger Burton West

Guest
bob prohaska's usenet account wrote:

>I'm a smallish rider, recently obliged by a broken foot to ride
>my dad's Nexus-8 equipped Breezer. It's a wonderful bike, easy
>to ride and immensely convenient, but the hub does not seem up to a
>very strong rider. The gearing will "slip", after a shift, not changing
>gears but losing engagement and then recovering.


Other people have already suggested not shifting under load... I'd also
recommend taking a look at the adjustment, as my Nexus 8 has a nasty
tendency to slip out of line when the bike's been transported by other
means.

It was great for learning to ride, it's ideal for urban riding where I
rarely get up to a high speed, and for me it's fine on all but the
steepest hills.

Roger