Author Topic: dirty oil  (Read 1853 times)

Andre Jute

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Re: dirty oil
« Reply #15 on: January 22, 2022, 09:00:27 PM »
This:
This idea of adding white spirit to the cleaning oil/extreme winter oil is crazy
I thought so too, when it came up elsewhere it was pointed out that White Spirit isn't even a standardised thing, there's three main types and variations within them.

Just on my desk here, today for current projects, are two bottles of "white spirit" labeled as containing aliphatic hydrocarbons and orange terpenes, plus who-knows what else, one described as an "effective, powerful and efficient solvent for oil paint" and the other as "use to blend colored pencils, wax pencils and oil pencils". Who wants to bet the price of a Rohloff gearbox, plus spoking in, transport and nuisance costs, that the paper filters in the Rohloff box aren't waxed to protect their fibers against destruction by the Rohloff oil? I don't know for sure, because I'm not a chemist, but I'd bet a smaller amount of money that "orange terpenes" (added to white spirits to make them smell less ugly) are acidic.

Or I can reach behind my desk into my paintboxes for several kinds of white spirit with one thing in common, that they have fast-drying properties; they don't even mention that the fast drying is achieved by adding resins to the distilled white spirit. Who wants to introduce a high-efficiency hardening paste into his Rohloff gearbox? That's what these resins in the white spirits are.

If I went into this properly, I could probably scare y'all rigid, but that's just what I can see in my study among stuff used with pencils, without even going into the room where I keep the more violent kinds of white spirit and selecting only the nastiest.

Which leads me to the next point, that any white spirit you buy at the hardware store or the supermarket (I have some to clean printing press accessories and equipment), except the kind that is pricier than Rohloff oil because it is purified before the desirable (to artists) additives are mixed in, has all kinds of impurities in it of the kind that the seals are supposed to keep out, like common dust, which with any oil makes a grinding paste. Mixing white spirit of unknown origin and processing into your Rohloff cleaning and extreme cold oil would bypass the seals before, perhaps, destroying them. Yech.

***
Referring to PH and Martin's tales of servicing Shimano hub gearboxes: I can remember when the Shimano kit for servicing their Nexus gearbox hub cost STG pounds 38 but for Euro 45 you could buy a brand-new Nexus box nicely spoked into a first-class rim in November when the discounters or even the factories sold off the previous year's unused wheels to clear space for new stock long since ordered. That was in 2002, only twenty years ago.

hendrich

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Re: dirty oil
« Reply #16 on: January 23, 2022, 04:23:42 AM »
The Rohloff oil/fluid is not that expensive when buying in bulk for yearly oil changes. The oil coming out is very black and I am reminded of similar blackness when changing car oil. I am not interested in using alternative fluids, a Rohloff lasts a long time and I don't feel alternatives are worthwhile. Probably, once a year with 25 mL cleaning fluid is satisfactory. Given that this bunch of thoughtful people have not suggested that 50 mL fluid is better, I'll stick with 25. Thanks.

martinf

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Re: dirty oil
« Reply #17 on: January 23, 2022, 09:30:09 AM »
I have a Sram Dual Drive hub, I have never opened it and have no intention of doing so.  It is on my folding bike, works great.  Occasionally I drip a few drops of oil into the drive side hollow axle where the shifter rod threads into it, that is all.  For those of you that are not familiar with the hub, it is a three speed hub like a Sturmey Archer, but it can take a Sram or Shimano 8 or 9 speed cassette.  I can't fit a front derailleur to my folding bike so this is how I expanded the gearing range.

I have had a couple of Dual Drive hubs in the past.

I used one on an old Moulton where it would have been very difficult to fit a front derailleur. It was a very suitable set up for wide-range gearing on a small wheel (16") bike as it allowed the use of reasonably-sized chainrings and sprockets to get a "normal" spread of gears. The other I used for a while on a 26" bike, but I eventually decided that an 8-speed hub gear suited me better for the kind of riding I did with that bike. After my 16" wheel Moultons started breaking up I bought a 20" wheel Moulton TSR and transferred one of the Dual Drive hubs to that, after I sold the TSR I also sold both Dual Drive hubs.

I took both the hubs to bits when I first got them, to clean out all the grease. As I usually do with Sturmey and SRAM hubs I used outboard motor grease in the accessible outer bearings and oil instead of grease on the internal parts, at the time Sturmey-Archer oil, if I was doing that nowadays I would use either synthetic gearbox oil or Rohloff oil, both work well without gumming up the pawls or attacking plastic parts like some oils can do.

I found the internal gears on the Dual Drive hubs to be very efficient. And light for a gear hub. I reckon any efficiency losses compared to a pure derailleur system were cancelled out on the 16" Moulton be being able to use larger sprockets, a 13T rear sprocket is theoretically a few percent better than an 11T.

martinf

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Re: dirty oil
« Reply #18 on: January 23, 2022, 09:48:11 AM »
Decades ago I bought a used three speed bike, had a Sturmey Archer hub with drum brake.  The previous owner had oiled it enough that oil had gotten into the brake linings.

That is a common problem with the old oil-lubed Sturmey Archer three speeds with drum brake.

I have a more recent version, which uses light grease instead of oil.

This is fitted to an old bike, previously used for visitors and now used occasionally by my wife when she doesn't want to risk locking up her "best" bike in town.

On that hub, I don't do my usual "oil instead of grease" lubrication.

Instead, I use a very thick grease in the bearing on the brake drum side, the recommended NLGI-0 grease for the internal and my usual NLGI-2 outboard motor grease for the two accessible bearings on the sprocket side.

My reasoning is that the "barrier" of thick grease should be viscous enough to stop any of the light grease migrating towards the brake linings.

As greases dry out slowly over time, I very occasionally (about every five years or so) strip the hub, clean out the old grease, and renew with the same three greases.

Doing that has worked so far. I suppose it is about 15 years or so since I got the hub.   

B cereus

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Re: dirty oil
« Reply #19 on: January 23, 2022, 10:19:28 AM »
Regarding the black colour of used oil, I always assumed that it was due to wear debris from the metal to metal contact within the hub. However when  the original CGOAB article appeared a friend who owns  a Mercury contacted me to ask my opinion. I did some on line research and it may be that there's another explanation.

The high phosphorous content of the Crazy Guy analysis is indicative of an extreme pressure (EP) oil and the black colour may be due to the rather complex chemistry underlying the way that such EP oils work. Briefly, the heat produced locally by the extremely high pressures results in chemical bonding to the iron at the surface of the steel to form an organo-iron-phosphide layer, which acts like a soap to reduce wear. The organo bit is a long chain hydrocarbon and when this layer eventually breaks down a small amount of carbon is released. This may well be responsible for the black colour of used oil.

Incidentally, Phosphorous isn't the only EP additive used. Similar compounds of Sulphur and Boron can be used and it may well be significant that there is no Sulphur in the Rohloff oil analysis. I don't know if there are any brass or bronze components in the hub but the Sulphur additives can react with the copper in these alloys to produce particles of copper sulphides. These are extremely hard and produce a grinding paste that will actually accelerate wear. A very good reason, I would have thought, for sticking with the Rohloff product.

mickeg

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Re: dirty oil
« Reply #20 on: January 23, 2022, 12:20:45 PM »
My philosophy on my Nomad Mk II was that the Rohloff was expensive, the oil was also quite expensive compared to other oils but it was a bargain in bulk (250ml bottles) compared to the cost of the hub. 

If the hubs had a reputation for lasting five to eight years, I would not have paid that much for the hub, and if I had obtained a hub with that short of a lifespan, I probably would have used kerosene for a cleaning oil and synthetic gear lube for the hub.  My Jeep Comanche pickup truck is long gone, but I still have a jug of synthetic 90W140 gear lube that I used in the differential.

But, when I bought my Rohloff hub in 2013, it already had a reputation from 15 years of production for lasting forever, or as close to forever as that many years of production can imply.  So, it made sense to buy the designated oil in bulk and use the specified oil.

Most of my distance is ridden on derailleur bikes, not my Rohloff bike.  But still even with low mileage on that bike the cost of oil is no more than pennies per hour of riding.

I built up my Nomad from the frame.  I built it up for heavy touring, CSS rims for long life span, etc.  Spent the extra money for S&S couplers, which have paid for themselves in reduced airline fees.  But I did not waste money either, I bought a $30 (USD) crankset on Amazon because it was strong enough to last and be reliable.  I bought some $8 generic brand chainrings because they were good enough.  And I have been using the cheapest KMC chains.  I could have spent more on bling, but the UN55 bottom brackets had a great reputation, so that is what I used.  I tried a few different brakes and ended up using some Tektro brakes that were $11 (USD).

My philosophy was for a robust reliable bike that is easy to repair and with components that are easy to replace and readily available.   

I wish they still made UN55 bottom brackets, they have replaced that model with a lower budget one.  Because it is an uncommon size with a 73mm width, I have  a spare (the new  cheaper model) on the shelf.

In other words, I did not waste money for the bragging rights for bling.  But where it looked like a good idea to spend money, like on bulk Rohloff oil, I spent that money to have that robust reliable and easily repairable bike.

And my original Amazon crankset and other low budget parts are still holding up just fine.