Grease is the word; a complicated word...

General cycling advice ( NOT technical ! )
Randy_Butternubs
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Joined: 16 Jun 2017, 8:32pm

Re: Grease is the word; a complicated word...

Postby Randy_Butternubs » 13 Apr 2018, 10:24pm

Fantastic thread!

You say you use Finish Line grease and I see that they do a ceramic version too. They also make ceramic chain lube. "Ceramic" obviously covers a lot of different materials but I'm not sure why you would want any in there. Do you think this is just marketing guff or is is actually better?

Their blurb read "A unique formulation features sub-micron ceramic particles, Teflon fluoropolymer and premium non-toxic synthetic oils" so I do wonder if it is just their normal PTFE grease with a few ceramic particles chucked in to trick people out of their money.

I've been interested in using semi-fluid grease in wheels for a while now. Do you find it needs topping up often enough to be a bother or it it usually fine. I pretty much only use midrange Shimano hubs if that matters. Also, do you have any recommendations for SFG?

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Grease is the word; a complicated word...

Postby Brucey » 14 Apr 2018, 12:42am

the finish line ceramic grease has hexagonal boron nitride in it. I don't know how much but it may be enough to make the grease the slightly grey colour that it is. Hexagonal boron nitride is an 'electron analogue' of the graphite structure and therefore has a lot of properties in common with it. I don't know how it compares with the PTFE grease because I have not tried both in the same applications.

Semi-fluid grease works pretty well in hubs; unlike other greases it shouldn't interfere with the operation of the freehub pawls. If the seals are even half-way decent (which covers most shimano hubs) the leakage rate is acceptable. However if there is much of a surplus inside the hub there may be quite a lot oozing out in the first few rides, which usually settles down. For example if I use a grease gun full of SFG on a slim-barreled shimano freehub, (so it is entirely full of grease) then the hub might disgorge about a teaspoonful in the first few hundred miles which still leaves plenty inside.

Repeat treatments once a year ought to be enough, and the grease that is disgorged is likely to be the most contaminated.

The grades that are easiest to buy are a bit like gear oil with thickeners (being made for gearboxes without seals good enough to hold a good fill of oil -a description which covers most IGHs in fact- ) and don't have a full load of solid lubricants or corrosion inhibitors. The stuff I use I make myself, and does.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

User avatar
The utility cyclist
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Joined: 22 Aug 2016, 12:28pm

Re: Grease is the word; a complicated word...

Postby The utility cyclist » 14 Apr 2018, 4:01pm

viewtopic.php?f=5&t=42374&hilit=moly
I'm sure the Castrol SBX (A No.2 NGLI grease) is indeed a very good grease for low speed applications but there are other Moly Disulphide greases available in the UK with similar properties and at a much lower cost (because they don't carry the brand name uplift in price).

As I mentioned in the thread 8 years ago, the very small difference in performance between the Castrol SBX/SKF type greases, including the Mobil 460 (also a No.2 an NLGI rated grease, SHC 1500 et al and those that cost much less is so small as to not be significant both in outright performance and protection(IMHO). Indeed the graphite in the Castrol SBX and SKF greases is more likely to have a (not significant) detrimental effect on performance in terms of drag to those greases without the graphite added.

And again unless you were able to do a side by side test over a long period with same loads, same speeds, same weather conditions and same servicing interval then inspect microscopically the interfaces you could never find out how much if any difference it has in real world use.

Basically I said that paying much more, often 2x, 3x, 4x and up for the 'best' grease isn't necessarily worth it but of course each person has their own decision and what they believe to be the 'best' and will pay almost anything for it which is fine. No-one is stopping anyone from paying top dollar for anything I just personally don't believe it is worth it, not when the research and data itself gives no indication that the greases with graphite/No.2 greases have any significant benefit over the other moly disulphide greases.

Castrol SBX is available from Australia from a retail POV, £10 or thereabouts for a 450g tube plus of course postage, SKF LGEM2 seems to be available in the UK for just under £12
Or buy a 500g tub of Moly Disulphide grease for £5 including postage in the UK from other well known brand names.

Very long posts whilst great for a small handful makes it less useful for the majority, basically TL-DR.

Put in a table for x use with y lubricant as a suggestion as to what you think is best for the application and possibly a link to where to buy would be massively more useful for the vast majority than a mini novella.

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Grease is the word; a complicated word...

Postby Brucey » 14 Apr 2018, 6:29pm

thanks for the feedback, but

a) as I took some pains to explain typical MoS2 greases are definitely not as good as some others are.... so why you might think otherwise is quite beyond me....

and

b) the 'mini-novella' is to explain why there isn't a simple list of 'use grease X for Y etc' In many cases there is more than one grease that will meet a given application.

I am not in the business of recommending one brand of grease over another per se, just trying to explain why you might choose one grease instead of another. I have (of course...) not tried everything on the market (there are thousands of greases out there) even if I have found some that work OK, and have some understanding of why that is.

BTW the idea that 'a thin lubricant is less draggy' is certainly not always the case when under load; a glimpse at a typical Stribeck curve and at the results of recent research shows very clearly that at low speeds the more viscous greases may push you into spending more time in the EHD regime and this can result in much lower friction coefficients- for example just spinning a wheel unloaded is quite misleading in this respect, most of what you feel may be seal drag and that may be only a tiny component of the true drag once the bearing is under load.

In a nutshell (and as I mentioned previously) commoditised greases that are recommended for such tasks as car wheel bearings (or indeed any high speed use) are unlikely to be anywhere near as good as they could/should be for bicycle uses. In fact the speeds and pressure loadings on bicycle bearings have a lot more in common with (say) crane slew rings than car wheel bearings, so I would say that you would always be better off with a grease meant for the former rather than the latter.

Also note the idea that spending £2 on a pound of cheap grease is a smart move vs spending five times that on a decent grease is a deeply flawed notion in most cases. As I mentioned if (as a typical cyclist) you buy one lb of decent grease and use it to conventionally service your few bicycle hubs, pedals etc it may last you five or ten years. You don't need to spare many (indeed any....) parts from destruction to make spending the extra money very much worthwhile; if decent grease merely extends the service interval then you might be spending, oooh, as much as £2 a year to achieve that end. Only a real nut-job would claim that isn't 'good value'...

Cost comes into it a bit more if you fit grease ports into parts that have a large volume and regrease regularly; you might get through 1 lb a year that way if you have a few bikes set up that way. Even so it is hardly a major expenditure.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

slowster
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Joined: 7 Jul 2017, 10:37am

Re: Grease is the word; a complicated word...

Postby slowster » 14 Apr 2018, 10:09pm

And again unless you were able to do a side by side test over a long period with same loads, same speeds, same weather conditions and same servicing interval then inspect microscopically the interfaces you could never find out how much if any difference it has in real world use.


You seem to be implying that such a side by side test would be impractical or difficult, or at least that is what I infer from what you have written. And yet arguably the bicycle offers the possibility of performing just such a test, since there are two pedals which will experience very similar (if not identical) loads and conditions, so it would 'simply' be a case of using a different grease in each pedal, and then comparing them after suitably testing use. That is probably the tricky part: riding in sufficiently testing conditions frequently/long enough for any significant difference between the greases' performance to reveal itself, especially since good quality pedals will have seals which will delay the ingress of the water, salt and mud which are needed to put the grease to the test.

I imagine that a comparison of different grease in front and rear hubs might not be quite so valid because of variations in the loads and possibly greater likelihood of contamination entering the rear hub, but it might still be worthwhile. Similarly there are two jockey wheels, which could presumably provide a good test of non semi-fluid greases, since unlike most other bicycle bearings they lack seals. The Chris King external bottom bracket, which can be purged with fresh grease with a dedicated tool, would also allow different greases to be compared (or equally comparison of regular purging of one side with fresh grease vs. no regreasing of the other).

Such testing is something I have been wondering about now for a while. It's the sort of thing that probably no commercial cycling magazine would ever do, despite the interest and possible importance of the subject. It's far easier to write a short puff piece on the benefits of ceramic bearings, than to scientifically determine the most appropriate lubricants and the optimum lubrication regime.

Very long posts whilst great for a small handful makes it less useful for the majority


Perversely I think the opposite is the case. For the small minority who regularly take apart their pedals, hubs etc. and clean and re-grease them (or who have fitted grease ports), I suspect that the frequency with which the old grease and any contaminants etc. in it are removed means that they might see far less benefit from the optimum grease for that application than the majority of lazy so and so's like me who are, to put it mildly, less than scrupulous in maintaining our bikes.

I think that for many of us our interest in this subject lies in better understanding how little maintenance we can get away with. If a one-off strip down of a hack bike and application of grease A in place of grease B used in the factory means that the bike will then last an extra two or three years before it needs new hubs/wheels/pedals etc., then that is useful to know. Similarly some of the reports I have seen of corrosion in hub gears on this forum and elsewhere on the internet indicate that the type and frequency of lubrication of hub gears can make a huge difference to their likely lifespan and trouble-free performance.

In a sense our interest in the subject is the same as the various industries for which the countless different types of grease were developed. Those businesses are concerned with identifying the optimum lubrication for their equipment: changing grease can potentially significantly prolong the lifespan of expensive equipment, as well as reduce costly planned and unplanned downtime. Consequently a lot of research and money have been devoted to improving knowledge and improving the products available. If cyclists can take advantage of that knowledge and those products, I'm all for it.

Airsporter1st
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Re: Grease is the word; a complicated word...

Postby Airsporter1st » 16 Apr 2018, 9:30am

CV joint grease usually contains a higher (50%) percentage of MoS2, but the difficulty is that very few manufacturers/distributors state what percentage is contained within. One way around this is to buy good quality MoS2 powder (plenty on eBay) and add it to your own, lower content, grease. Whilst doing that, have a look at tungsten disulphide - its even “slippier”

JakobW
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Location: The glorious West Midlands

Re: Grease is the word; a complicated word...

Postby JakobW » 16 Apr 2018, 11:17am

Thanks for this Brucey; I can honestly say I'd never expected to be waiting avidly for the next instalment of a treatise on grease! In the past you've recommended Land Rover swivel joint grease as an off-the-shelf SFG suitable for bicycle use; is that still the case?

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The utility cyclist
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Re: Grease is the word; a complicated word...

Postby The utility cyclist » 16 Apr 2018, 12:56pm

Brucey wrote:thanks for the feedback, but

a) as I took some pains to explain typical MoS2 greases are definitely not as good as some others are.... so why you might think otherwise is quite beyond me....

and

b) the 'mini-novella' is to explain why there isn't a simple list of 'use grease X for Y etc' In many cases there is more than one grease that will meet a given application.

I am not in the business of recommending one brand of grease over another per se, just trying to explain why you might choose one grease instead of another. I have (of course...) not tried everything on the market (there are thousands of greases out there) even if I have found some that work OK, and have some understanding of why that is.

BTW the idea that 'a thin lubricant is less draggy' is certainly not always the case when under load; a glimpse at a typical Stribeck curve and at the results of recent research shows very clearly that at low speeds the more viscous greases may push you into spending more time in the EHD regime and this can result in much lower friction coefficients- for example just spinning a wheel unloaded is quite misleading in this respect, most of what you feel may be seal drag and that may be only a tiny component of the true drag once the bearing is under load.

In a nutshell (and as I mentioned previously) commoditised greases that are recommended for such tasks as car wheel bearings (or indeed any high speed use) are unlikely to be anywhere near as good as they could/should be for bicycle uses. In fact the speeds and pressure loadings on bicycle bearings have a lot more in common with (say) crane slew rings than car wheel bearings, so I would say that you would always be better off with a grease meant for the former rather than the latter.

Also note the idea that spending £2 on a pound of cheap grease is a smart move vs spending five times that on a decent grease is a deeply flawed notion in most cases. As I mentioned if (as a typical cyclist) you buy one lb of decent grease and use it to conventionally service your few bicycle hubs, pedals etc it may last you five or ten years. You don't need to spare many (indeed any....) parts from destruction to make spending the extra money very much worthwhile; if decent grease merely extends the service interval then you might be spending, oooh, as much as £2 a year to achieve that end. Only a real nut-job would claim that isn't 'good value'...

Cost comes into it a bit more if you fit grease ports into parts that have a large volume and regrease regularly; you might get through 1 lb a year that way if you have a few bikes set up that way. Even so it is hardly a major expenditure.

cheers

You've offered no evidence to support the performance/protection disparity you claim between a no.2 MoS2 grease and no.2 CASTROL/SKF MoS2 grease with added graphite, please do so.

I guess you don't know what NLGI means, go read the linked thread, who said more viscous, I didn't, no.2 MOS2 greases perform better than those with graphite added, this has been studied and found to be a fact, not significant but still more friction.

Who mentions £2 tubs of grease, I haven't, yet again making up stuff that hasn't been said? You keep saying stuff with no evidence to support it and then invent what I've said to push your unproven argument .
Last edited by Graham on 17 Apr 2018, 8:39am, edited 1 time in total.
Reason: Testing Mod's patience . . . again

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Grease is the word; a complicated word...

Postby Brucey » 17 Apr 2018, 10:22am

The utility cyclist wrote: ...You've offered no evidence to support the performance/protection disparity you claim between a no.2 MoS2 grease and no.2 CASTROL/SKF MoS2 grease with added graphite, please do so.


Your greases change name all the time...

I guess you don't know what NLGI means, go read the linked thread, who said more viscous, I didn't, no.2 MOS2 greases perform better than those with graphite added, this has been studied and found to be a fact, not significant but still more friction.


duh. Read what I've written. If you don't believe that go do some proper research.

Who mentions £2 tubs of grease, I haven't, yet again making up stuff that hasn't been said? You keep saying stuff with no evidence to support it and then invent what I've said to push your unproven argument .


you can buy a MoS2 grease with reasonable test scores for as little as £2 per lb. I can provide a link if you like. My point is that this grease (like many others) is suitable for high speed use in wheel bearings and is therefore certainly less than ideal for low speed bearings. There are good reasons for this which you appear not to comprehend. If you want it simple, try 'if it were not so, then different greases for low speed use would not be required'.

I'm not quite sure what you are driving at other than to display your ability to jump to wild conclusions (like I don't know what NLGI grades are.. :roll: ) and to have a pointless argument. You appear to be contributing little or nothing, and to have neither read what I've written nor understood it.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~