Nexus 8 hub durability

On Monday, May 3, 2021 at 12:05:50 AM UTC-5, bob prohaska wrote:

The total mileage can't be very high. It's been ridden maybe
5-10 miles per week for about 14 years.
I'd be more concerned about the 14 years than the number of miles. These hubs are lubricated with grease at the factory, and after that amount of time it probably needs replacement or at least "assistance".
The hub can be opened easily by removing the non-drive-side locknut and cone, requiring a 14mm cone wrench and a 14mm open-end wrench. If you watch the first 90 seconds of this (https://www.youtube.com/watch?v=k8qAn2D05R8) you will see all you need to know. (The rest is optional, because the guy isn't planning to reassemble the hub.)
Once the hub is open, you will be able to assess the condition of the lubrication. At a minimum, the gear cluster can be dipped into some oil (I use 75W-140 gear oil), and the bearings greased with wheel bearing grease. If the innards look really dirty, or parts are worn, you may elect to take another path (maybe a soak in mineral spirits?). Otherwise, just replace the gear cluster in the shell and adjust the bearings to your preference. I go with "zero pre-load, zero free play".
Here's another video that has good information: (https://www.youtube.com/watch?v=lFOMD2q5-o4). Dan Burkhart does a really nice job explaining internally geared hubs. He does more disassembly than is necessary here. Skip to 9:54 to see how the gear cluster is dipped into the oil. He uses ATF, which I have found to be too runny. I prefer the gear oil I mentioned, which is basically a 75W oil. It stays on the gears and has less tendency to leak. I'd recommend using a smaller vessel for the oil, too!
Steve

Steve Weeks wrote:
On Monday, May 3, 2021 at 12:05:50 AM UTC-5, bob prohaska wrote:

The total mileage can't be very high. It's been ridden maybe
5-10 miles per week for about 14 years.
I'd be more concerned about the 14 years than the number of miles.
These hubs are lubricated with grease at the factory, and after that
amount of time it probably needs replacement or at least "assistance".

The idea of taking the hub apart really doesn't appeal to me, given that it
works relatively well. I do agree that adding some lubricant can't hurt and
might help.

The biggest takeway from this thread is that the hubs aren't considered
fragile. It seems their worst attribute is poor sealing. For my neck of
the woods that's not a problem. The bike lives in the garage and I have
no need to ride in the rain.


The hub can be opened easily by removing the non-drive-side locknut and cone,

That's a useful hint. I didn't know about it, which is why I used thin
ATF instead of "real" gear oil.


Once the hub is open, you will be able to assess the condition of the
lubrication.

Not ready to go there yet, but the path is clear. I'll start with some oil.

(I use 75W-140 gear oil), and the bearings greased with wheel bearing grease.

With both oil and grease in the same space it seems the oil will dilute the
grease. Not necessarily bad, grease is just oil with a thickener. Rather
Like gravy 8-)


Here's another video that has good information: (https://www.youtube.com/watch ?v=lFOMD2q5-o4).

Good video, but it (and all the other videos I found on YouTube) refers to
the hub as "Alfine". Mine doesn't say Alfine, just Nexus, with a red band.
Are they basically the same?

Many thanks to everyone who replied!

bob prohaska

On Wed, 5 May 2021 02:32:41 -0000 (UTC), bob prohaska
wrote:

That's a useful hint. I didn't know about it, which is why I used thin
ATF instead of "real" gear oil.

"What to Consider When Lubricants Mix"
https://www.machinerylubrication.com/Read/29983/when-lubricants-mix
"When different types of oils and greases are mixed together, it can
spell disaster for machinery. This is why it’s best to avoid mixing
lubricants."

This article claims that ATF is a good substitute for Shimano original
"oil". Calling it "oil" instead of grease makes me wonder about the
validity of the suggestion. My guess(tm) is that it's a bad idea:
https://bicycles.stackexchange.com/questions/51008/degreaser-and-oil-recommendations-for-nexus-8
Some of the other advice about cleaning is fairly good. If you pour
any solvent into the hub, make sure you get it out of the hub after
cleaning and re-lubrication.

Teardown of Nexus 8:
https://www.youtube.com/watch?v=k8qAn2D05R8 (13:18)
and reassembly:
https://www.youtube.com/watch?v=JNuyvIZvCrs (31:03)
After tearing it apart, he used an ultrasonic cleaner and degreaser to
remove the old grease.

https://www.amazon.com/SHIMANO-Internal-Hub-Grease-100g/dp/B001GSOO0M
Only $25 for 100 grams. Ouch. Kinda looks like white lithium grease,
but I wouldn't want to risk a substitute if the real grease is
available.

Good luck.



--
Jeff Liebermann
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

On Wednesday, May 5, 2021 at 3:57:48 AM UTC+1, paraphrased advice from an internet source
:
Some of the other advice about cleaning is fairly good. If you pour
any solvent into the hub, make sure you get it out of the hub after
cleaning and re-lubrication.

This is rat**** advice even after correcting the order of actions it advises.

The pro way to clean dirty oil out of a gearbox you still want to use for many years is to rinse it with a thinner oil of the same type that you intend to use permanently. Rohloff for instance has two oils they specify and supply every year, a general use oil and a lighter weight severe winter use oil. The winter oil is also the cleaning oil. The old oil is run out through the service port, a measured quantity of winter oil is run in with a syringe, then the gearbox is rotated in two gears for a few minutes each or a few kilometres on the road, which ensures that the oil reaches all the gear and axle and bearing surfaces, then the now-dirty cleaning/winter oil is run out by simply turning the gearbox upside down, after which clean oil (either normal or extreme cold/cleaning type according to riding circumstances) is run in. The Rohloff service interval is 5000km/3000m or one year, whichever comes first,
and it doesn't matter if all the loose oil in box is lost because 12-14ml will stick tenaciously to the mating surfaces until the service is due.

While nobody, including its maker, knows what Rohloff's expected service life is (there are some out there going strong after a quarter-million miles), Shimano publishes, or used to publish, a service life number for the Nexus, which if I recollect correctly was 50,000km or about 30,000m. The service interval for the oil bath was 5000km/3000m. But you could go on the net and discover Shimano Nexus boxes in service way beyond the official MTBF, and a few with rather a short life in the hands of brutes like me. The estimable Chalo said that "A Rohloff is run in just about when a Shimano Nexus lies itself down to die." (Paraphrased from memory.)

I suspect Bob's Nexus Premium, leading a low stress life, will outlive him, service or no service. But some oil or grease will raise the suspicion to a betable chance of survival. However, unless Bob intends taking the box apart and cleaning all its components very thoroughly, he'd better stick to the Shimano official oil bath, which requires no disassembly beyond merely taking the assembled and self-contained gubbins of the box out of its shell in the centre of the wheel. That's the only way he can be certain he's not mixing incompatible oils/greases/magic potions.

I'm rather impressed with the HALT sign before mixing oils or greases. The Rohloff on my Utopia Kranich has the external gear change which has a component called a click box which is removed by a simple thumbscrew and then exposes the point where the cables rotating (Rohloff gear-change is a pull-pull systems, no cable pushing) act directly on the gear shaft which is topped by an 8mm hexagonal brass end which is the part meant to be greased. It comes from the factory with some unspecified grease in the clickbox. I cleaned it out with a tissue at the normal service interval and put in some white teflon which I like because it is clean. Worked fine. Then a fellow on another conference kindly sent me a tube of Phil. I cleaned the Teflon out, I thought well enough, and put in some Phil. In less than 500km, it made the most god-awful water-thin mess, obviously with no capability in mating-surface protection. I gave the removable parts a couple of turns in an ultrasonic bath I bought for cleaning watch parts and cleaned the parts I didn't dare remove several times with artist's white spirit (the most refined kind you can buy without finding a medical supplier) and tried again with the Phil. This time it remained green but still thinned too soon for my liking. Long story short: after several cycles of cleaning, I now have the Phil's in the click box surviving and serving 5000km, which is the main gearbox service interval, which was my target. Infinitesimal traces of disparate greases can be very troublesome.

Andre Jute
Live and learn.

On 5/4/2021 9:57 PM, Jeff Liebermann wrote:
On Wed, 5 May 2021 02:32:41 -0000 (UTC), bob prohaska
wrote:

That's a useful hint. I didn't know about it, which is why I used thin
ATF instead of "real" gear oil.

"What to Consider When Lubricants Mix"
https://www.machinerylubrication.com/Read/29983/when-lubricants-mix
"When different types of oils and greases are mixed together, it can
spell disaster for machinery. This is why it’s best to avoid mixing
lubricants."

This article claims that ATF is a good substitute for Shimano original
"oil". Calling it "oil" instead of grease makes me wonder about the
validity of the suggestion. My guess(tm) is that it's a bad idea:
https://bicycles.stackexchange.com/questions/51008/degreaser-and-oil-recommendations-for-nexus-8
Some of the other advice about cleaning is fairly good. If you pour
any solvent into the hub, make sure you get it out of the hub after
cleaning and re-lubrication.

Teardown of Nexus 8:
https://www.youtube.com/watch?v=k8qAn2D05R8 (13:18)
and reassembly:
https://www.youtube.com/watch?v=JNuyvIZvCrs (31:03)
After tearing it apart, he used an ultrasonic cleaner and degreaser to
remove the old grease.

https://www.amazon.com/SHIMANO-Internal-Hub-Grease-100g/dp/B001GSOO0M
Only $25 for 100 grams. Ouch. Kinda looks like white lithium grease,
but I wouldn't want to risk a substitute if the real grease is
available.

Good luck.




I don't know but we've had good results (happy customers,
long service life) with the same 90 gear oil we use in other
planetary systems, white grease for end bearings and seals.

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

On 5/4/2021 9:32 PM, bob prohaska wrote:
Steve Weeks wrote:
On Monday, May 3, 2021 at 12:05:50 AM UTC-5, bob prohaska wrote:

The total mileage can't be very high. It's been ridden maybe
5-10 miles per week for about 14 years.
I'd be more concerned about the 14 years than the number of miles.
These hubs are lubricated with grease at the factory, and after that
amount of time it probably needs replacement or at least "assistance".

The idea of taking the hub apart really doesn't appeal to me, given that it
works relatively well. I do agree that adding some lubricant can't hurt and
might help.

The biggest takeway from this thread is that the hubs aren't considered
fragile. It seems their worst attribute is poor sealing. For my neck of
the woods that's not a problem. The bike lives in the garage and I have
no need to ride in the rain.


The hub can be opened easily by removing the non-drive-side locknut and cone,

That's a useful hint. I didn't know about it, which is why I used thin
ATF instead of "real" gear oil.


Once the hub is open, you will be able to assess the condition of the
lubrication.

Not ready to go there yet, but the path is clear. I'll start with some oil.

(I use 75W-140 gear oil), and the bearings greased with wheel bearing grease.

With both oil and grease in the same space it seems the oil will dilute the
grease. Not necessarily bad, grease is just oil with a thickener. Rather
Like gravy 8-)


Here's another video that has good information: (https://www.youtube.com/watch ?v=lFOMD2q5-o4).

Good video, but it (and all the other videos I found on YouTube) refers to
the hub as "Alfine". Mine doesn't say Alfine, just Nexus, with a red band.
Are they basically the same?

Many thanks to everyone who replied!

bob prohaska



For lubrication, Nexus and Alfine are not different.

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

Jeff Liebermann wrote:
On Wed, 5 May 2021 02:32:41 -0000 (UTC), bob prohaska
wrote:

That's a useful hint. I didn't know about it, which is why I used thin
ATF instead of "real" gear oil.

"What to Consider When Lubricants Mix"
https://www.machinerylubrication.com/Read/29983/when-lubricants-mix
"When different types of oils and greases are mixed together, it can
spell disaster for machinery. This is why it?s best to avoid mixing
lubricants."

No lube seller wants his products mixed with those of a competitor. I
tend to think that's more a matter of marketing than chemistry. There are
a few special cases, like sulfur compounds attacking brass surfaces, but
they're rare and fairly specific.


Teardown of Nexus 8:
https://www.youtube.com/watch?v=k8qAn2D05R8 (13:18)
and reassembly:
https://www.youtube.com/watch?v=JNuyvIZvCrs (31:03)
After tearing it apart, he used an ultrasonic cleaner and degreaser to
remove the old grease.

That one is a sort of demolition derby 8-). This is better for my purposes:
https://www.youtube.com/watch?v=tJvGnrDBTNA
Despite it having Alfine in the title a Nexus is shown also in passing.
Apparently the two are the same in terms of lubrication..

Thanks for writing, and your good wishes!

bob prohaska

On 01/05/2021 20:38, bob prohaska wrote:
Does anyone on this list have experience with Shimano Nexus-8 red band
hubs?

I've been using one on a grocery getter (Breezer Uptown 8) for several
years. Most of the time it's wonderful, but the hub still make nasty noises
from time to time during shifts. I've fussed with the shift cable adjuster
and _usually_ remember to ease up on the pedals when shifting. Probably
upwards of 95% of shifts are perfect, maybe more.

Not had that problem with mine.

Still, on occasion something seems to slip with a sharp noise, like a
pawl has slipped a tooth. Subsequent operation has so far been quiet
and normal.

They all do that Sir, at least mine did as well.

It gives the impression the hub is fragile in some sense. Do Nexus 8
hubs have significant breakage problems? I'm no powerhouse rider, the
terrain is quite flat.

They aren't a Rohloff, but should be good for 1,000 miles or more,
longer if you oil bath them. I switched to Alfine-11 and an annual 30
minute oil change and all seems good at about 15,000km.

On Thursday, May 6, 2021 at 7:26:52 PM UTC+1, Tosspot wrote:
I switched to Alfine-11 and an annual 30
minute oil change and all seems good at about 15,000km.

Unless you're a wrecker or unlucky, you should get 50K from an Alfine, which has better everything than the Nexus. -- AJ

On Tuesday, May 4, 2021 at 9:57:48 PM UTC-5, wrote:

"What to Consider When Lubricants Mix"
https://www.machinerylubrication.com/Read/29983/when-lubricants-mix
"When different types of oils and greases are mixed together, it can
spell disaster for machinery. This is why it’s best to avoid mixing
lubricants."
This may be true in general. However, I have been using the synthetic gear oil on two Nexus-8 hubs and one Nexus-7 for 15 years with no adverse effects. This has involved dipping the gear clusters without prior removal of the grease.
Each time I service the hubs, I look at the bearing races for signs of wear; so far, none. One of these hubs has about 10,000 miles of service, mostly in the winter.


https://www.amazon.com/SHIMANO-Internal-Hub-Grease-100g/dp/B001GSOO0M
Only $25 for 100 grams. Ouch. Kinda looks like white lithium grease,
but I wouldn't want to risk a substitute if the real grease is
available.
The first Nexus hub I serviced was a 7-speed, and I used the "official" Nexus grease. It looked like a molybdenum disulfide type of lubricant. The next Nexus was a "regular" 8-speed (as opposed to red-band) and it was lubed with the same grease. When I opened the red-band Nexus-8, I was surprised to see the white lithium-like grease. I have used the black Nexus grease on all these hubs' bearings with no apparent ill effects.