The right grease

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Mick F
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The right grease

Postby Mick F » 22 Sep 2010, 11:20am

In my thread about headsets and indexing, CJ suggested:
Cyclenut wrote:...... Quality of grease is also key, it needs to be very resistant to channelling, with a high viscosity base oil and/or EP additives......
This sounds like a perfect grease for all applications on a bike.

Does anyone have any idea what sort of grease it is?
Where do you find out about the best greases?
Mick F. Cornwall

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Mick F
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Re: The right grease

Postby Mick F » 22 Sep 2010, 11:37am

PS
Just found a tub of Constant Velocity grease that I've had for a while from when I worked on cars.

It says:
A high quality lithium based No2 grease with added molybdenum disulphide (MoS2), ideally suited for CV joints or homokinetic joints. High in extreme pressure additives to give long life under heavy loads. Also ideal for chassis, wheel bearings, hubs, and universal joints. ....................... Includes a laminar solid lubricant which overcomes boundary lubrication.
(My emphasis)
Is this any good for headsets, hubs and other bicycle bearings?
Mick F. Cornwall

kwackers
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Re: The right grease

Postby kwackers » 22 Sep 2010, 11:58am

Personally I think whatever you've got to hand will do. Bicycles aren't particularly demanding, if it doesn't wash away it's probably good...
(Given your maintenance regime, you could probably get away with lard I'd have thought Mick... :lol: )

Exceptions probably are - people who spin the pedals at over 10,000 rpm, and people over 100 st who do a lot of 'grinding'. They should search out specialist advice.

Winkeladvokat
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Re: The right grease

Postby Winkeladvokat » 22 Sep 2010, 12:27pm

I use Rock n Roll Super Web:

http://www.chainreactioncycles.com/Mode ... delID=2611

Noticeably more "persistant" than standard lithium based grease, good stuff IMO.

Winkeladvokat
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Re: The right grease

Postby Winkeladvokat » 22 Sep 2010, 12:37pm

Also, this stuff looks interesting:

http://www.motorex.com/index.cfm?oid=11 ... tragId=169

Grease is grease as far as bearing performance goes, but there have been too many occasions when I've stripped down components to find them dry when using lithium grease - there are longer lasting greases out there!

GrahamNR17
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Re: The right grease

Postby GrahamNR17 » 22 Sep 2010, 12:45pm

When I was a trainee lab rat at Aldermaston many years ago, I was once lectured extensively by a metallurgist as to why I should always use a moly grease on my bicycle and any other mechanical contraption where metal moved over metal. Many hours later, after sitting through microscopy photo after microscopy photo, I have never dared use anything else :| And to the same 3lb tin of the stuff is still in use today. Maybe it's why I've only ever replaced bearing cups and cones on things that arrived worn out, and never anything I've fitted new. Maybe I've just been lucky. Either way, his adenoidal tones still ring fresh in my ears and I still dare not use anything else :?

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Re: The right grease

Postby kwackers » 22 Sep 2010, 12:54pm

GrahamNR17 wrote:Maybe it's why I've only ever replaced bearing cups and cones on things that arrived worn out, and never anything I've fitted new. Maybe I've just been lucky. Either way, his adenoidal tones still ring fresh in my ears and I still dare not use anything else :?

One of the biggest reasons bearings wear out is because they're fitted too tight, fitted by 'tapping' them into place with an hammer or simply allowed to dry out. Once the surface of either the cup or ball is damaged (even slightly) then wear is inevitable (and fast) regardless of what you use for grease.

When you look at the speeds and loads of a bicycles bearings they're at the bottom end of what some bearings are subjected to. Mind you the bearings they used do tend to be at the cheaper end of the spectrum (I just paid near £400 for a pair of bearings for the spindle on my milling machine - and they're not that big!) so I guess that needs to be taken into consideration too.

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Mick F
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Re: The right grease

Postby Mick F » 22 Sep 2010, 1:20pm

GrahamNR17 wrote:When I was a trainee lab rat at Aldermaston many years ago, I was once lectured extensively by a metallurgist as to why I should always use a moly grease on my bicycle and any other mechanical contraption where metal moved over metal. Many hours later, after sitting through microscopy photo after microscopy photo, I have never dared use anything else :| And to the same 3lb tin of the stuff is still in use today. Maybe it's why I've only ever replaced bearing cups and cones on things that arrived worn out, and never anything I've fitted new. Maybe I've just been lucky. Either way, his adenoidal tones still ring fresh in my ears and I still dare not use anything else :?
These words are music to my ears!
I've had this tub for years too, though unused for some time too. It's still good in its sealed tub, so I can see me trialling it in headset and hubs.

It wasn't expensive, so why isn't this grease used all the time?
Mick F. Cornwall

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Re: The right grease

Postby rjb » 22 Sep 2010, 1:22pm

Graham wrote
always use a moly grease on my bicycle


I used to use a tub of Castrol Molybdenum disulphide grease - only problem with it was that it was very black and Mrs rjb allways noticed it on the bathroom towels :oops:
At the last count:- Focus Variado, Peugeot 531 pro, Dawes Discovery Tandem, 2 Dawes Kingpins, Falcon K2 MTB dropped bar tourer, On One Pompino, Longstaff trike conversion on a Falcon corsa. :D

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Re: The right grease

Postby cyclingthelakes » 22 Sep 2010, 1:38pm

kwackers wrote:Personally I think whatever you've got to hand will do. Bicycles aren't particularly demanding, if it doesn't wash away it's probably good...
(Given your maintenance regime, you could probably get away with lard I'd have thought Mick... :lol: )

Exceptions probably are - people who spin the pedals at over 10,000 rpm, and people over 100 st who do a lot of 'grinding'. They should search out specialist advice.


For bearings, more complex parts of machinery, surely the below using moly grease I agree with. But for basic tasks, to make a screw and bolt work together well, really anything slick can suffice as a quick fix. I keep Olive Oil in my tool kit to massage the handlebar wrap from time to time and to tighten something up, I know I've used basic petroleum jelly before.

GrahamNR17 wrote:I was once lectured extensively by a metallurgist as to why I should always use a moly grease on my bicycle and any other mechanical contraption where metal moved over metal. Many hours later, after sitting through microscopy photo after microscopy photo, I have never dared use anything else :| And to the same 3lb tin of the stuff is still in use today. Maybe it's why I've only ever replaced bearing cups and cones on things that arrived worn out, and never anything I've fitted new. Maybe I've just been lucky. Either way, his adenoidal tones still ring fresh in my ears and I still dare not use anything else


But I find this a good note as well as some others, it is easy to pack to many bearings in thinking the more, the better.

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Re: The right grease

Postby kwackers » 22 Sep 2010, 1:52pm

cyclingthelakes wrote:For bearings, more complex parts of machinery, surely the below using moly grease I agree with. But for basic tasks, to make a screw and bolt work together well, really anything slick can suffice as a quick fix. I keep Olive Oil in my tool kit to massage the handlebar wrap from time to time and to tighten something up, I know I've used basic petroleum jelly before.

If you've got the stuff you should use it, but my point was I wouldn't go out of my way to buy something special. (Although I'd draw the line at olive oil or petroleum jelly - good for lubricating plastics though.)

But I find this a good note as well as some others, it is easy to pack to many bearings in thinking the more, the better.

Worth noting you can over pack with grease, in machinery it can cause the bearings to overheat. Given the low power of bicycles I don't know how much of an issue this could be but it would probably affect the bearings efficiency.

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Mick F
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Re: The right grease

Postby Mick F » 22 Sep 2010, 2:13pm

What are homokinetic joints?


Just found out:
Constant velocity joints.
Mick F. Cornwall

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CJ
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Re: The right grease

Postby CJ » 22 Sep 2010, 2:14pm

The main bearings of a bicycle are actually rather demanding, or so I was informed several years ago, by John Southey: a keen CTC member who also happened to be an applications engineer with Mobil Lubricants. He'd applied the techniques of his profession to the analysis of his hobby, and found that although bicycle bearings are subject to only moderate forces, these are concentrated on very small areas, due to the low conformity (dis-similarity in curvature) between balls, cups and cones in traditional bearings, or the very small balls to be found in any cartridge bearing that can be fitted in the same space. To understand what follows you need to realise that ball bearings do not actually have point contact, but compress slightly, as does the surface of the race, to make contact over a small elliptical area of shape and size dictated by their elastic properties and relative curvatures.

A lubricant acts like a cushion, increasing the effective size of the contact area so as to keep contact stress below a level that fatigues the underlying metal (leading to the pitting we have all probably seen on a hub cone etc.). Oil makes a particularly good cushion thanks to some special viscous properties of oil, in which its resistance to being squeezed out of a small gap increases dramatically when you squeeze it faster and harder. More viscous oils do this all the better, but the extreme pressure performance of a relatively thin oil can be boosted by "EP" additives. It's important to understand at this point, that grease is oil, mixed with a binder, usually some sort of soap. The binder acts like a sponge, releasing oil to do its lubricating job when squeezed, then mopping it up again - before it has time to escape. The binder also gives the grease its sealing properties and determines resistance to water etc. But the oil does the actual lubricating.

Bicycle bearings also rotate very slowly, which gives lubricants more time to escape from the path of the rolling ball, so this makes the lubrication problem all the more taxing. On the plus side, low speed means there's no chance of the grease overheating. This is a significant problem however, for the majority of other applications, which means that common greases that you'd buy for the car etc. will be less viscous than you really want for your bike bearings. And since most other machines have proper seals, these greases probably won't be all that good at keeping the water out either.

So what you want on a bike is a grease that has a high viscosity base oil (and/or a good dose of EP additives) in a binder with excellent sealing and water resisting properties that is also highly resistant to channelling (getting pushed aside and not flowing back). The one John Southey came up with from the range offered by his company was Mobilgrease SHC-PM. This is something they originally tailored to the requirements of the heavily loaded, slowly rotating rollers at the wet end of a paper mill. Slow, heavy, wet and dirty - sounds like a bicycle to me! Anyway: it's really good stuff, with the added bonus of being nice to handle, in that it gets its performance from a high viscosity synthetic base oil rather than EP additives (which smell like tomcats by the way!). I bought enough of that to last me a few years. But Mobil's product range has not stood still, and from the several similar greases now offered I'd probably choose Mobilith SHC 1500.

Some of the greases that are (expensively) repackaged for the cycling market may well be similar stuff - or maybe not. The suppliers just don't provide the sort of data that might enable me to really tell. So I'm sticking with the industrial stuff, where I know what I'm getting.
Chris Juden
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Mick F
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Re: The right grease

Postby Mick F » 22 Sep 2010, 2:21pm

Thank you Chris!
Now, where do we buy this lovely pink/red SCH 1500?
Mick F. Cornwall

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CJ
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Re: The right grease

Postby CJ » 22 Sep 2010, 2:40pm

Mick F wrote:Thank you Chris!
Now, where do we buy this lovely pink/red SCH 1500?

Last time I bought any it was from Senator Lubricants in Crawley, but that was several years ago and I'm not sure they're still in business. The downside of industrial purchasing is you may have to buy quite a large minimum quantity! But nowadays you can profitably dispose of any surplus on Ebay.
Chris Juden
One lady owner, never raced or jumped.