FiftySix

I finally got around to pulling the Nexus 8 IGH apart on my new to me 2013 Norco Cityglide.

I went cheap with materials I had. Sometimes that works out, sometimes not.

Anyway, I flushed the hub out with ATF and filled it back up with some heavy gear oil, then greased the ball bearings and clutch bearings.

Now my once silent Nexus 8 makes clacking noises while coasting in gears 5 through 8. It used to only do that if I back pedaled in those gears.

I guess I'll be going back in. Grease the pawls, then?

Like the title says, "Arrrrgh".

AnkleWork

Maybe follow a known-good procedure with the materials you have? Search this forum to learn from others' experiences.

tcs

Fun fact: gear oil viscosity is measured at different temperatures than motor oil. 75W-90 gear oil runs through a viscometer about like 10W-30 motor oil.

FiftySix

I used some Castrol 85W-140 I had on hand because the ATF ran right through like a wash. It sure washed out quite a bit of dark gray dirty lube.

I wonder what the motor oil equivalent to 85W-140 is?

FiftySix

True enough.

I did read about some people using ATF for the gears and grease for the bearings.

I'm thinking I need to grease the pawls? Not sure.

tcs

Quite possibly a good decision. 'ATF' isn't all the same stuff. Some of it is as little viscous as 3wt motor oil.

In the old days, Sturmey-Archer recommended (and sold) 30wt (motor) oil for their gear hubs. For the last ~25 years the factory has lubed with NLGI 00 semi-fluid grease.

Shimano came up with the oil dip re-lube method for their 7- and 8-speed IGHs after dealers refused for any amount their customers were willing to pay to disassemble, clean and re-lube with the factory semi-fluid grease.

FiftySix

Thanks for the feedback. The company I work for used to keep a 55 gallon drum of semi-fluid grease for grease pumping systems on machinery. I sure could use some of that, I think.

sweeks

For my 2 Nexus 8 hubs I use gear oil (75W-140 synthetic) on the gears and wheel bearing grease on the bearings. I found ATF to be too runny.
Also, FWIW, the 75W-140 works well in my Alfine 11-speed hub, which now has 6,500 miles on it. I use "Royal Purple Max Gear", which is about $20 a quart... quite a bit cheaper than the Shimano oil.

EDIT: FWIW, I found this about viscosity ratings:
Viscosity is notated with the common "XW-XX." The number preceding the "W" rates the oil's flow at 0 degrees Fahrenheit (-17.8 degrees Celsius). The "W" stands for winter, not weight as many people think. The lower the number here, the less it thickens in the cold. So 5W-30 viscosity engine oil thickens less in the cold than a 10W-30, but more than a 0W-30. An engine in a colder climate, where motor oil tends to thicken because of lower temperatures, would benefit from 0W or 5W viscosity. A car in Death Valley would need a higher number to keep the oil from thinning out too much.

The second number after the "W" indicates the oil's viscosity measured at 212 degrees Fahrenheit (100 degrees Celsius). This number represents the oil's resistance to thinning at high temperatures. For example, 10W-30 oil will thin out at higher temperatures faster than 10W-40 will.
(source: Lubricants)

So basically, the first number is "proportional" in some way to viscosity (resistance to flow; a measure of internal friction). A "75" weight oil will flow less readily than, say, a "30" weight oil. The higher number is basically irrelevant to use in a bicycle hub, which would not be expected to reach 100 degrees Celsius under normal conditions.

FiftySix

Thanks for that feedback, sweeks.

Does your Nexus 8 hubs make pawl clicking noises in gears 5 through 8 while coasting with that 75W-140 oil?

My Nexus 8 hub used to be a stealth machine in 5 through 8 while coasting, before I serviced it with the 85W-140 oil and bearing grease.

Now, my hub makes the same noise as back pedaling, but while coasting in the upper four gears. Stealth mode is now gone.

Reynolds 

I took apart my Nexus 8 (non red band) at about 6,000 kms, drilled and threaded it for an oil port (5/32" screw) and used ATF since, changing it every 5,000 kms or so. Never greased the bearings or pawls. It stills works flawlessly after 42,000 kms.

FiftySix

Thanks for the reply. My hub is non-red band as well.

What is your preferred type of ATF? I'm guessing your hub coasts nearly silently in all gears?

Reynolds 

I use regular ATF leftover from my car, don't remember the brand right now. There's still half a can remainining and the hub only needs about 15 ml each time,so it will probably outlast the hub (or me).
My hub is silent while riding but makes a faint clicking sound if I push the bike backwards. Normal according to Shimano, never had a problem with that.

FiftySix

It would seem that the gear oil I used is actually too thick. I'll try some ATF this weekend.

I believe that is normal, too.

Thank you for the follow up.

GamblerGORD53

I have two SA hubs. Right from the start I figured that 10w30 lawnmower oil would be too thin.
So I looked at everything at Canadian Tire, and came home with Wynn's 80+ old motor additive.
I put 20% in the oil and it works fabulously. I also wanted it to play better with my Krazy greased bearings. It still gets washed into the oil, but doesn't seem to bother anything. My SA 5w is faster than anything else I have ridden.

I sure have no use for a port hole. Only seepage is up the indicator rod. It will go 4,000 miles easy. I do have to watch the cone oozing by the drum brake.

Reynolds 

My hub does "sweat" a bit, but I can live with that. It's better than having to disassemble it.

sweeks

Funny thing: I have 2 Nexus 8 hubs, one plain and one "red band". They both are used on my old Dahon Mu XL, which is my dedicated "winter" bike. The plain hub's wheel is equipped with a studded tire; the red band is in a wheel with a normal tire. Since I have another bike that I ride in the better weather, the winter bike usually does not get the red band hub. So the red band hub had sat over a year after the last time I dipped the internals when, recently, I needed the bike in "non-winter" format, and changed to the red band wheel. I noticed the clacking noise when coasting, just as you described. I wasn't too worried about it, as the hub was working perfectly. However, after a week or so of daily riding, the noise stopped. Maybe it took that long for the oil to reach all the pawls, or whatever was making the noise. Anyway, I hope this happens to your hub.
Steve

FiftySix

Very interesting, sweeks. Very interesting indeed.

FiftySix

As a follow up, yesterday I pulled the hub apart and filled it up with 85W140 again. Apparently, I left a lot of air in there the last go around. Shame on me.

Anyway, the pawl clacking noise is greatly reduced to being almost unnoticeable. That was after only one ride last night. Time will tell if the noise further reduces like you mentioned, sweeks.

Thanks for all the feedback everyone.

MajorC

I'm interested in doing this, can you describe where you drilled the hole? Please provide pictures if you can.

Reynolds 

The location is critical, because there's a steel ring inside the aluminum body and you don't want to touch it. Since you must disassemble the hub to drill it, you can measure inside to find the right place and translate this to the outer side. The bolt should be small, I used a 4mm one but started with a 2mm drill bit to be sure it was in the right place. It was, but I could've corrected it if needed.

MajorC

I wonder if it could be located like the oil drain in the alfine 11

MajorC

By the way I read somewhere that you could just add some oil (not sure what kind) somewhere in the to sort of rejuvenate the grease and it's good for a rather long while again.

Winfried

Shimano Hub Gear Oil Port

You could use this drain plug from Rohloff.

MajorC

thanks, took note of this..