Oil instead of grease?

[breakwellmz]

the problem with putting oil in hubs that are not oil-tight is that you need to keep doing it, which people generally won't do if they weren't doing it before. In bad weather oil can be washed out of bearings in a fairly short period of time and this usually is why more is needed on a regular basis.

The semi-fluid grease I have developed contains corrosion inhibitors and its thixotropic nature means it is fully mobile within the hub (like oil) when in use but doesn't leak out when the bike is standing (like grease). It is thin enough that you can use it in hubs originally meant for oil, despite their weak pawl springs etc. It leaks out so slowly that you just need a shot once a year or so to keep most hubs sweet. Its other additives and high base oil viscosity mean that is a better lubricant than anything else I have ever put into an IGH, too.

Overall, it is infinitely better than most oils, greases, or ad-hoc mixtures thereof.

cheers

Morning Brucey.

How is it that my motorcycle power unit manages to contain half a gallon of hot oil under pressure,yet the same can`t be said of most bicycle hub gears?
I assume that If the same sort of seals used on gearbox output/kickstart/gearlever shafts were used on the bicycle hub that excess friction would be the issue.

[julianm]

Enough is enough - here is your answer :

[Brucey]

...How is it that my motorcycle power unit manages to contain half a gallon of hot oil under pressure,yet the same can`t be said of most bicycle hub gears?
I assume that If the same sort of seals used on gearbox output/kickstart/gearlever shafts were used on the bicycle hub that excess friction would be the issue.

well the oil isn't under pressure per se because the crankcase/gearbox has a breather, anf the rotating part is small where it matters (poking out of the casings). If the engine cases were whirling around the crank then it would be a fairer comparison with (say) a bicycle hub gear.

The seals are not a million miles away from those that are used on sealed cartridge bearings. Such seals are indeed a little draggy, so the bearings that are used on bicycle hubs often have lower pressure on the seal lips. When such seals are new, they are still quite effective; I have run some sealed hubs in oil from new and it hasn't leaked out at any great rate provided the seals are in good condition.

Things like car engines and motorcycle engines/gearboxes can and do leak a small amount, but small leaks are generally tolerated, where the same leak on a bicyce component would soon empty the component of oil.

cheers

[PDQ]

So is the consensus that, all things being equal, grease is a much better option for bicycle applications? The slightly higher resistance being outwieghed by far greater lubricating longevity and much better water resistance.

[Brucey]

I guess so; if the sealing isn't perfect (and it usually isn't) then oil is only OK provided it is a little and often, and it doesn't rain too much in the meantime.

Otherwise grease -in some form or other- is your only option.

cheers

[breakwellmz]

Enough is enough - here is your answer :

You wouldn`t be alluding to British motorcycles like the Royal Oilfield,i mean Enfield`DRIPPING`oil would you?
Glad to say that my Nexus 7 doesn`t leak the EP90 gear oil it run on

[xcalibur]

I have never seen anything close to a tight or sealed nexus hub? Even amply mounts of grease gets pushed out, but there are lots of nexus models and I have not seen them all. How thick is EP90 oil? I think the regular recommended oil is SAE 20, but people have had success with lots of different oils and greases. I am trying the lightest ever on my Sturmey Archer AW 3 speed, Finish Line Wet Ceramic Lube. It is very smooth and light running, but I don't know of far from ideal it is even when I apply often. I have noticed some synthetic lubricants feel smoother both on the chain and in hubs, at least compared to regular medium thick mineral oil.

[Brucey]

in terms of protection for slow speed bearings etc under load, the most viscous oil is the best. This shouldn't be confused with the thickness of greases; the lubrication in greases comes from the oil in them and the thickness comes from the, er, thickener part. You can have quite thick greases which have a fairly thin oil in them and have similar lubrication properties to thin oil as a consequence.

Oil weights have a meaning in terms of viscosity, but you can't compare gear oils and other (e.g. SAE) oils directly; a 70W gear oil is roughly equivalent in viscosity to a 30W engine oil or something. Neither is viscous enough to provide good protection in low speed, high load applications.

So (unless you are interested in a single race or something where low friction -even at the expense of increased wear- is the #1 priority) the most viscous oil is the best thing to use; this may be kept in place by it being one ingredient in a grease or a semi-fluid grease. The best greases for low speed high load applications have base oils that are incredibly viscous, and they usually have a cocktail of other ingredients that confer anti-galling, EP lubrication, solid lubricants, anti corrosion additives etc.

In a hub gear, only if the lube interferes with the operation of the pawls is it 'too thick', but a viscous oil with a little thickener is a much better lube than a thin oil and a lot of thickener (which is more commonly the case... ).

When looking at greases with specific ingredients, you can be pretty sure that they are something good if (say) the same stuff is used of choice in applications where (say) industrial plant costing millions is kept working under the toughest conditions. You can be equally sure that if such lubricants are not used in such applications, you can probably do a lot better...

If considering the use of less viscous oil, it is as well to remember that you may get less drag under low loads (everything feels 'nice and smooth') but if the lubricant film breaks down under higher loads -as it will do with a less viscous lubricant- the friction may increase just when you need it to least.

cheers

[xcalibur]

Aarghhh Brucey, the subject of oils and lubricants is getting more difficult by the minute here. I initially thought the differences between them where more like finer points, not major. I went for synthetic, teflon and ceramic just to see if there might be an advantage with the newer technology (newer than 1970 at least).

[Brucey]

IMHO Finish Line grease is a good grease for bicycle use; but this is because it is clean in use, doesn't separate badly, doesn't wash out too easily, doesn't dry out too quickly and contains a high quality synthetic base oil of reasonably high viscosity. Where teflon and ceramic fall on the usefulness-to-BSness spectrum I am less sure about. I reckon there are certainly better lubricants out there for specific purposes, but you won't find them in Halfords, and even if you could, you mightn't choose to use them on some bicycle bearings.

cheers

[123malford]

http://www.caltex.com.au/productsandser ... px?ID=1633
So would this have an application ? I'm thinking more of my freewheels as I'm fairly happy dripping SAE 30 into the Sturmey Archer, and it hasn't complained since 1975. Bar oil definitely stays better on the chainsaw than if I use motor oil instead.

[Brucey]

for things like open freewheels (i.e. without seals) the very best lubricant I have used to date was a particular aerosol motorcycle chain lube (that, annoyingly, I can't buy any more.... ).

This had enough solvent in it that it was very fluid and would penetrate an open bearing, but then set into a gel. The gel in question was loaded up with EP agents, a very thick oil, and plenty of corrosion inhibitors. This lube was not easily washed out, and resisted the attack of salt water better than almost anything else I have tried. The result was that on bikes that saw severe winter use, freewheels, pedal bearings and even hub bearings could be lubricated easily and one dose would usually last a winter.

Because it was unlikely that you would (say) fill a freewheel completely, there was no chance of the pawls being sticky with excess grease.

Good chainsaw oils are basically like gear oils (they usually have some EP additives in them I believe) with an additional thickening (or tackifying) agent so that they are not so easily flung off the chain in use. They may not resist road salt corrosion especially well, and (depending on how far they have taken things) may drain out of open bearings during storage, leaving very little behind; this may just take longer than with a normal oil. In use, anything with a coating of the oil may pick up dirt rather a lot. Some of these features are shared with other lubes too. It might be that they are just the thing for some jobs but I'm sure they won't suit everyone. If the chainsaw oil is thick and gel-like, it may be that adding some solvent may inprove its ability to penetrate a freewheel bearing. If it penetrates easily without solvent, it probably won't persist all that well.

cheers

[123malford]

thanks. I had been using, on the freewheels with a hole drilled in the body, similarly an aerosol motorcycle chain lube, by Rock Oil (Warrington) . It did feel a bit too draggy and I was cutting it with a bit of a squirt of GT 85 -- all a bit haphazard but did resist the winters quite well. I wonder which one it is you can now no longer source ? Those freewheels where there was no oil port, well those just had to have oil --- I had thought about trying Phil's Tenacious Oil but it had crossed my mind that maybe this was just repackaged chainsaw bar oil -- at a nice profit. http://www.philwood.com/products/gohc/oilngrease.php

[Brucey]

I used to use a Castrol chain lube. I think they may have stopped doing it because it was black and fairly disgusting; they mostly seem to be pretty colours these days...

The castrol stuff could be squirted into most bearings through even tiny gaps and would provide good lubrication in even small amounts; most are thicker than that when first applied.

You might be right about Phil Wood oil, but then it could have almost anything in it; there are enough different candidate additives etc that lubricant chemists are a bit like chefs, each having their special recipes....

I think that the gels etc that are used in chain lubes are not quite right for freewheels in that they are not thixotropic enough; (if they were, the lube would likely fly off the chain in use). By contrast some other lubes are sticky enough to persist fairly well but are nothing like so draggy because they shear easily. Striking the right balance is tricky and I daresay there isn't a single lube that will suit everyone or every freewheel. I know exactly what you mean about cutting the lube with something else, but going too far washes it out....

cheers

[JonMcD]

On the same general topic, with the last two "bicycle greases" I bought the oil and soap have separate over time. I am looking at a tub of Rock N Roll Super Web Grease I bought a couple of years ago and it has pools of oil on top of it. I left the same grease in a grease gun under light compression from the spring plunger and the oil seeped everywhere within weeks. I have several 30 year old tins of "car grease" in the garage (from the days when cars had grease nipple everywhere) with no signs of separation.
Anyone know why this separation seems a characteristic of the greases sold for bicycle bearings, or am I just extrapolating from the particular to the general?