Greasing the roller clutch & hub shell on a shimano nexus
From: dajjalix <dajjalix@...>
Sent: Saturday, 24 November 2012, 23:15
Subject: [Geared_hub_bikes] Greasing the roller clutch & hub shell on a shimano nexus
Can anyone who has actually worked on the nexus hubs comment on their practice of lubricating the roller clutches and the hub shell?
- I just lubricated mine (SG-8R36, no brake) for the first time this past weekend. It only had a few hundred miles on it but I wanted to check for loose metal, winter-proofing, curiosity, etc.
I bought the outrageously expensive blue oil and did a dunk per http://thegoldenwrench.blogspot.com/2011/01/servicing-of-internally-geared-hub.html. I used Liquid Wrench marine grease on the bearings and under the dust caps.
I found that I needed to inject a significant amount of grease around/behind the planetary gears in order to quiet the hub down (I assume the degreasing caused this).
Functionally, the hub is back to normal (which means it still hesitates to change gears under heavy pedaling but is fine in all other modes) but I do hear a faint freewheel-like noise when I coast in gear five or higher. The noise goes away entirely if I shift into one through four. I'm still trying to figure that out but it doesn't sound ominous so I'm going to do some more reading before I disassemble again.
- --- In Geared_hub_bikes@yahoogroups.com, "hughckelley" <hugh.kelley@...> wrote:
>I do hear a faint freewheel-like noise when I coast in gear five or higher. The noise goes away entirely if I shift into one through four.
I have a Nexus SG 8R-35, and have exactly the same noises in gears 5 to 8,only when freewheeling and not when pedalling, after doing a dip and regrease. Although the noise is somewhere between a normal freewheel clicking sound and a clackity sound.
A bit of hub history.
I have it on my main commuting bike, used in all weather,with quite a bit of rain, live in a coastal town but don't ride it on the beach. I serviced the hub for the first time after 2.5 years and 3700km. I had been coming and going from home over that time so it would sit for a couple of months at a time.
When I opened it up, the original shimano grease looked really good, without that brown sludgy look if water had got in. Only the small caged ball bearing on the brake side was a little dirty. The bearing races on both sides were in good condition and there was no rust in the hub.I was pleasently surprised, as my previous 2 nexus hubs both had rust problems when I opened them up.
I split the internals into 2 after removing the one circlip, cleaned the internals in kerosene, then I dipped in Castrol chainsaw bar oil, and used Castrol Marine grease.
The hub has done another 1000km since the service.
I only noticed the annoying noise in the last month, but I have to say I am I bit slow up top, so I actually can't recall exactly when the noise started. It might have been straight after the service or it could have developed progressively louder over time. I just can't say.
Now going back a few years, I had a Nexus SG 8R-25 build on my touring bike. My memory is really vague on this one, but it definately developed a clakity sound when freewheeling. I can't remember when it started but it did get louder over time. Whether it was there in a quieter tone before I serviced the hub, I just don't know. That service would not have had an oil dip, but just a regrease.
I have been thinking that the problem could be how much grease I apply, and where I actually place it. It could be that I am putting too much grease on certain parts that restrict their movement. The test would be to service again, remove all the grease in the hub, just do an oil dip, and test ride the bike for any noises. Then learn exactly where grease should be applied. I'm away from home at the moment, so won't be doing that for a few month's.
Hope this helps you, but I too am more than a bit worried about the noise, even though the hub still functions well.
- Colin, after digging into the literature a bit, I'm betting that the noise we're hearing is coming from the "disc" clutch when it is engaged (stage II, speeds 5-8) but not being actively driven by the cog. See parts 9 and 11 here:
I also considered the roller clutches as a source of the noise but I don't think that's possible because:
a) The "stage I" roller clutch would make a noise whether I'm pedaling or not in speeds 5-8 (it should always be "outpaced" in those speeds)
b) The "stage II" roller clutch would also make the noise when freewheeling in speeds 1-4, which mine does not.
Like you, I don't yet know if it's too much or too little (or the wrong type of grease entirely), but I intend to pop mine apart in the next few days. Unfortunately, I think it requires a Shimano tool to remove/inspect behind the clutch.
- Degreasing and oiling the nexus/alfine hubs has been widely reported to make them louder. As oil is nowhere near as effective a sound damper as grease, this isn't surprising or necessarily a sign of any defect or problem.
- I popped mine open again today and added more grease around the clutch. Now I have the opposite issue, a (louder) clicking when I pedal in 5-8 and silence when I coast.
Maybe this means I'm working on the right spot, but perhaps with the wrong grease?
I may ride it gently as-is next week and see if it quiets down as the grease centrifuges itself into a happy place (I only rode it a few blocks today after the lube).
So you lubricated the roller clutches with marine grease?
How much did you use?
Did you lubricate all of the roller clutches?
Did you put grease on the inside of the hub shell?
- Yes, post-dip I smeared the exterior of the roller clutches with marine grease. I did hit all of the clutches, I did not bother putting any grease on the shell (assuming the clutches and bearing would handle that).
After riding to work today all of the noises have gone. The only remaining issue is that the hub behaves in a semi-fixed fashion. With the bike on a workstand, when I spin the rear wheel the pedals move right with it (it still freewheels with the resistance from feet on pedals). I'm interpreting this as another sign of roller clutch over-greasing.
For those of you who know more than I do about grease specs, here they are (http://www.grainger.com/Grainger/LIQUID-WRENCH-Marine-Grease-6NGX0 ):
NLGI Grade GC-LBI'll probably ride as-is for a few weeks and then relube at least the roller clutches mid-winter with a more Shimano-like grease (saving the marine grease for the salt/slush/water-facing bearings and dustcaps).
Dropping Point 554 (290)
Base Calcium Sulfonate
Film Type Thick Grease
Specific Gravity .96
Characteristics Corrosion Protection
Application Harsh Environments
- --- In Geared_hub_bikes@yahoogroups.com, "hughckelley" <hugh.kelley@...> wrote:
> Colin, after digging into the literature a bit, I'm betting that the noise we're hearing is coming from the "disc" clutch when it is engaged (stage II, speeds 5-8) but not being actively driven by the cog. See parts 9 and 11 here:
I've been away from the internet for a few days.
I'm not that skilled with the actual theory of how the hub works. My basic understanding is if the hub is clicking when freewheeling, then that is a pawl running over the teeth of the ratchet track. My noises are more of a clackety sound, not such a sweet sounding hub. I'll have to wait till I pull it apart, to see if I pumped any grease into that disc clutch area.
Just a thought. Looking on Aaron's shop page - Shimano Internally Geared Hubs, The grease he uses, appears in the photo's to be not as thick as the stuff I use, but I am just guessing that from appearances.
- I have seen many roller clutches over the years. Notably Shimano's Silent Clutch freehub. Many of those would fail. Also I have seen it used in exerciser machines for silent coasting indoors. The failure of small roller cultches is forward freewheeling. They just stop working. I have taken several apart and cannot see any wear really. I suspect the diameter of the ring increases over time.
I have already seen Alfine rollers slip, but it was only the smaller ring and it was easily solved with very light grease. Thick grease seems to make them slip.
Aaron's Bicycle Repair
--- In Geared_hub_bikes@yahoogroups.com, "hughckelley" <hugh.kelley@...> wrote:
> Yes, post-dip I smeared the exterior of the roller clutches with marine
> grease. I did hit all of the clutches, I did not bother putting any
> grease on the shell (assuming the clutches and bearing would handle
> After riding to work today all of the noises have gone. The only
> remaining issue is that the hub behaves in a semi-fixed fashion. With
> the bike on a workstand, when I spin the rear wheel the pedals move
> right with it (it still freewheels with the resistance from feet on
> pedals). I'm interpreting this as another sign of roller clutch
> For those of you who know more than I do about grease specs, here they
> are (http://www.grainger.com/Grainger/LIQUID-WRENCH-Marine-Grease-6NGX0
> <http://www.grainger.com/Grainger/LIQUID-WRENCH-Marine-Grease-6NGX0> ):
> NLGI Grade GC-LB
> Color Red
> Dropping Point 554 (290)
> Base Calcium Sulfonate
> Film Type Thick Grease
> Specific Gravity .96
> Characteristics Corrosion Protection
> Application Harsh Environments
> Standards GC-LB
> I'll probably ride as-is for a few weeks and then relube at least the
> roller clutches mid-winter with a more Shimano-like grease (saving the
> marine grease for the salt/slush/water-facing bearings and dustcaps).