Chain Lubrication - A Competitive Edge

[mountain_lion]

 

Ok' date=' then I'll be the first to say something NICE about JB.

I feel for you, and I appreciate your input. Unlike most hubbers who simply say "Do not use wax based lube", you'll say "do not use wax based lube because ..... And to demonstrate that this is true you can do ....." That's REAL input. It's better than people saying: "Wax lube is $hit. Don't use it"

Sometimes I've seen him get sarcastic about people following media hype. I feel for him. In my line of work there's also a lot of media hype, and people believe it all without THINKING about it beforehand. I'm not a fundi on the REAL technicalities behind cycling gear, and I appreciate it when JB points out media hype and EXPLAINS why it's not true.

As for him being sarcastic about general posts: Well, look how everyone is flaming him when he's giving HIS opinion [he has a right to post his opnion just like everyone else']. And when he disagrees with someone [and gives hard FACTS] people start flaming him up. :-/ I feel [and this is MY opinion] that most of his sarcasm can be justified.

JB, keep on posting.

 

Well said Ctrl-C.

 

JB, your input is appreciated on the Hub, sarcastic or not.

 

 

 

 

[controlc]

Ask Johan Boringman...

 

And then we still ask why he's always sarcastic?

[Bikalot]

Be careful with high pressure washers. It has been said that they can force water into your hubs. Not sure how true this is' date=' but it is not hard to imagine it is. Seals on hubs are not very tight as they need to allow for very low friction. Probably not good for your BB bearings either.

Try fitting a powerlink. Personally I use a powerlink on my training bike, but a normal link on my racing bike. Powerlinks make it really easy to clean the chain. Just unlink, wash in a bit of diesel, dry thoroughly, link again and apply lube. Works wonders!

[/quote']

 

in diesel?

[controlc]

in diesel?

Yip. Diesel. Haven't tried it personally' date=' but apparently it works OK.

 

And someone mentioned something about an oily substance in diesel [or was that paraffin?'] which is also a

[Bikalot]

in diesel?

Yip. Diesel. Haven't tried it personally' date=' but apparently it works OK.

 

And someone mentioned something about an oily substance in diesel [or was that paraffin?'] which is also a

 

i used to work in a bike shop few years ago and we were told diesel was a big no no,dont know why though

 

we used to use parrafine

[The_Break]

Hi Casspir.

 

We all know that chains lengthen right? Easy to see when you hang an old chain next to a new chain. Don't say I know exactly what the mechanism is, but I would think it would be due to the tension created in the chain when you are pedalling.

 

Metal has something called strain which is, simply put, a characteristic of a couple of factors, one of them being the force exerted on the metal, in this case a tension force. Simply put, if a graph of the force (x-axis) is drawn compared to the strain (y-axis) then the strain increases initially quickly with force and then starts to flatten off. Now depending on the material there are 3 things that happen when a force is applied:

 

1: Non-elastic strain: This is when the force is low and the metal just experiences a force. There is no movement between the tiny metal structures.

 

2: Elastic strain: This is when the force is near the top part of the graph where it becomes horizontal so to speak. There is movement between the tiny metal structures in the metal, however when the force is taken away the metal moves back to its original state. Just like an elastic.

 

3: Plastic strain: This is when the force is so great that it goes beyond the horizintal point on the graph (also where the graph would dip down for metal that have a plastic point) and the metal stretches so to speak. On removal of the force the metal does not spring back to its original position, however remains stretched to some degree.

 

So, that is what I think happens to a chain. It is the repeated big forces on the chain that slowly stretch it out over its life cycle. I also did a quick calculation with another thing called tensile stress and it falls within the general limits of what I was saying above.

 

Sorry for all the detail, but there really is no simple way to explain this theory.

 

Other than this I do not know what could make a chain stretch, but it definitely does and this is ultimately what helps to cause chain/sprocket/ring wear as the links do not seat due to the "changed spacing" of the little roller pieces and thus cause a bit of friction and wear. Obviously grit also plays a role.

 

In any case, if anyone tells you that chains do not stretch or lengthen then just ask the LBS what they use a chain guage for.

 

Hope this gives some insight?

The_Break2008-03-01 06:32:44

[The Guy in Pink]

.

 

We all know that chains lengthen right? Other than this I do not know ..........

what could make a chain stretch' date=' but it definitely does and this is ultimately what helps to cause chain wear as the links do not seat due to the "changed spacing" of the little roller pieces and thus cause a bit of friction and wear. Obviously grit also plays a role.

 

[/quote']

 

Hey The_ Break , This is some Wonderful Theory!  

Chain stretch is caused wear.

The pin and the pin hole wear as well as the rollers. The pin gets smaller, the hole gets bigger and the link spacing changes.  Take a  worn chain and stretch it out, it gets longer, link spacing longer.  Push the ends inwards it gets smaller, link spacing shorter. Try it!

[The_Break]

It may be because diesel could eat the frames paint or something like that. Maybe the "safety" (can actually only combust under high compression) factor too if the shop was worried about that. 

 

Not sure, but that is why I said remove the chain and dry thoroughly. I don't get diesel near my frame cause I am scared of the same thing. Used to use petrol, but was always worried about the safety factor of leaving it lying around. Kids with matches enjoy playing games!

 

Paraffin also works well I believe. Never tried it myself though.

[The_Break]

I think you hit the nail on the head!

 

Here's a nice article that covers a lot. http://www.sheldonbrown.com/chains.html

 

Thought I would give it a bash before steeling someone elses ideas.

 

I think you should be on TV rather.

The_Break2008-03-01 06:52:29

[dirtrider]

What is a chain ? If it is the links and stuff we all see then i have to agree with Yellow Saddle - It does not stretch ! It is the stuff that holds all these links together that srectches .

[Minion]

I've been away from work for all of 21 hours and am now going into

withdrawal (what a nerd), so I'll give a quick overview of some of the theory behind

chain wear and stretch.

 

Contrary to what others have said, the basic concepts in engineering are not that difficult to understand (we study for four years, not so much to learn them, but to know how and when to apply them).

 

Stress = Force / cross-sectional area. You'll get the same stress if you apply a big force to a fat object as you would applying a small force to a thin one.

 

Strain = Change in length / original length. Basically how much an object stretches when you load it. A 1km pipe has the same (10%) strain when stretched by 100m as a 1m pipe stretched by 100mm.

 

Every material has stress-strain curve. This essentially gives a simple illustration of what happens to it when you load it.

 

Here a typical one for a ductile metal (like steel):

http://www.pt.ntu.edu.tw/hmchai/Biomechanics/BMmeasure/StressMeasure.files/StressStrainCurve.jpg

If you apply a force (giving a stress), the equivalent strain (i.e. stretch) is shown on the red line.

 

If the force is low enough, you sit in the elastic region. This means that as soon as you release the force, the object goes back to its original size and position.

Take a steel ruler. Bend it a little bit. Let it go and watch it bounce back to its original shape. This is elastic strain.

 

Once the force goes high enough and causes the the yield stress to be exceeded, you go into the plastic region. The object is permanently deformed and does not return to its original shape.

Take you steel ruler. Bend it a lot. Let it go and watch it bounce back. It does not return to its original flat shape but is now bowed. This is plastic strain.

 

If  the force goes high enough to exceed the ultimate stress, your object will break.

Take your poor ruler. Try and bend it back on itself. At some point it will snap. You have now exceeded it's ultimate stress.

 

Note: you will never encounter a situation where applying a force results in no elongation (at least not with normal materials. Who knows what exotic stuff scientists will dream up next)

 

Take a break and get your popcorn and Coke.

 

How does this apply to chains?

Your chain will stretch whenever you apply force through your pedals; but since it's in the elastic region it will return to its original length as soon as the load is removed. No permanent deformation occurs.

 

So how might the metal in a chain stretch permanently?

By applying a force that produces stress in the plastic region. Apply this force and your chain is permanently stretched.

So why is this not the cause of chain elongation over time?

Plastic deformation occurs instantly. As soon as you hit that first 20% gradient hill at maximum power and 10 cadence, you will exceed the yield stress (maybe) and permanently deform the chain.

 

But maybe you have lots of these little deformations occuring over time leading to gradual growth in chain length?

No. The way metals behave means that once it has yielded, causing more permanent deformation requires you to apply an even higher stress than previously. The only way you can get more permanent chain deformation after the 20% hill is to go and find a 21% hill and do that at 10 cadence and max power.

 

Is they any way that a steel chain can slowly stretch over time when exposed to the same load?

Yes. It's called creep. Fortunately this only becomes a problem in steels at temperatures over 550?C or so. Global warming is not that bad yet.

 

So how do chains lengthen?

Chains lengthen over time due to the mechanical wear of the link plate holes and the pins, as described in the Sheldon Brown article linked by The_Break.

 

Final note: I did a quick calculation, and it is conceivable that you could produce enough force to yield or break a chain. This result does, however, depend heavily on assumptions about how much force you can produce at low cadences (Bruce?) and the exact steel that chains are made out of (Johan B?).

 

Now that that's off my brain, I can enjoy the rest of my weekend!

 

 

 

[Johan Bornman]

The_Break' date='

 

How does a chain stretch? 

 

I would really appreciate an explanation because I really don't know. 

 

Regards,

 

casspir

[/quote']

Ask Johan Boringman...

First time I ever saw him on TV, he said: (in heavy afrikaans accent) 'you cant stretch a chain'.

 

Bob, I can't see why my accent has anything to do with this debate. If there were two or three of us lookalikes and someone asked you which one is Johan, you may have said, the one with the Afrikaans accent, the other one with the Scottish accent is Andrew, and so forth. But with me talking solo, no need to bring my accent into play. I can only assume you meant it as some form of insult or derogatory remark. Well, I make no apology for my accent, as I have no doubt, half of the people on this forum won't make any apology either.

 

Perhaps you have an English accent and your Afrikaans is accented, who cares?

 

Your focus on accent tells me a lot about you though. I can just imagine you moaning about Tim Modise's accent or Vuyu Mbuli's accent or Ravi Naaidoo's accent.

 

It's called diversity and unless topical to the conversation, no more important than the colour of our eyes.

 

And as for the Boringman moniker, that's getting boring too. At least I have the guts to post under my own name.

 

 

[Johan Bornman]

Hi Casspir.

 

We all know that chains lengthen right? Easy to see when you hang an old chain next to a new chain. Don't say I know exactly what the mechanism is' date=' but I would think it would be due to the tension created in the chain when you are pedalling.

 

Cut cut cut cut.....So, that is what I think happens to a chain. It is the repeated big forces on the chain that slowly stretch it out over its life cycle. I also did a quick calculation with another thing called tensile stress and it falls within the general limits of what I was saying above.

 

Sorry for all the detail, but there really is no simple way to explain this theory.

 

 

Cut cut cut cut cut cut

 

 

In any case, if anyone tells you that chains do not stretch or lengthen then just ask the LBS what they use a chain guage for.

 

Hope this gives some insight?

[/quote']

 

Others seemed to have pointed out your errors insofar chain elongation goes. Allow me to summarise then:

 

1) Chains dont stretch, they elongage due to mechanical wear. The semantics are important here.

2) You cannot apply enough force with the available levers and muscle power you have to effect plastic deformation (stretch) of a bicycle chain.

3) Repeated forces below yield don't plasticly deform steel.

4) Strain is not applicable to metals only but to all materials experiencing a force.

 

I won't embarrass you further and ask you to show us your "Quick calculation" to prove that plastic deformation is indeed possible on a bicycle chain.  Nor will I ask you to elaborate on your theories about the cause and effect of wear in a sprocket and chain system.

 

You seem to think that I'm on your case. I am and here's why.

 

You happily dish out flawed advice on things you clearly have not applied your mind. Then you tell us there's no need for you to explain anything to us because it requires a broad base of mathematics and it is your field of expertise and we just won't understand. We must just trust you.

 

Then, you go one step further and let us all know that you're a mechanical engineer, have trained for years and therefore you are right. All of this anonymously, so your reputation remains intact even if your alter ego takes a knock or two.

 

On this tech forum neither tenure nor credentials rank higher than a clear argument with back-up proof. I've had people tell me they've been in the business for 20 years and therefore they're right and I've had people tell me they are a rocket scientist and therefore I should take their argument at face value. I kid you not on either of these two cases.

 

We'll it doesn't. Any rookie, no matter what his or her age or education is taken seriously when they present a good argument on a good foundation and make that argument in the open under their own good name. Many a clear argument have made me change my view of things, even here on The Hub.

 

I have no doubt that you have something to contribute and I'd like to see the Hub's expertise grow. I suggest you back off, lurk a bit, look at previous debates (I can assure you everything you see here today has been presented here many times before, this is just a time warp), analyse our previous cases and jump back in with useful counter arguments.

 

Things get a bit hot here from time to time and very few of the really interesting debates are all lovey-dovey. But we generally tend to stay out of each others' characters and dont get personal, with the exception of The Hub's resident village idiot who you'll soon recognise.

 

Perhaps this post is too long, I'll try and abreviate a bit more in future.

 

Regards

Johan

 

 

 

 

 

 

 

 

 

 

[bruce]

Final note: I did a quick calculation' date=' and it is conceivable that you could produce enough force to yield or break a chain. This result does, however, depend heavily on assumptions about how much force you can produce at low cadences (Bruce?) and the exact steel that chains are made out of (Johan B?).

Now that that's off my brain, I can enjoy the rest of my weekend!


[/quote']

 

Okay, I did a quick scan of some of my race data.  Highest torque applied through a 1.26 second period (the power meter averages torque and records the average every 1.26) is around 45 N-m recorded by a torque tube inside the rear hub.

 

I don't know the following:

The gear I was in when I recorded this torque.

The diameter of the torque tube that measures this.   Sorry, this is not relevant (inserted to confuse the student )

The amplitude of the torque wave through a pedal cycle, so I don't know what the instantaneous peak is.

But it's a starting point.

 

bruce2008-03-01 12:15:33

[Minion]

 

 

Okay' date=' I did a quick scan of some of my race data.  Highest torque applied through a 1.26 second period (the power meter averages torque and records the average every 1.26) is around 45 N-m recorded by a torque tube inside the rear hub.

[/quote']

 

Thanks Bruce.

I think I'm moving into the realm of flogging a dead horse on this thread, but I still want to do the calculation for my own curiosity.

 

Do you have the speed and cadence data for that measurement point? If you can also say what chainring and cassette sizes you had on your bike at the time, I think I can use all of that data to estimate the gear.

 

You (or maybe Bikemax) posted a link a while back comparing power outputs over various cadences and speeds (I think). I think it was brought up in the context of doing weight training (e.g. squats) to improve hill climbing. If I recall correctly, it concluded that you use at most 25% of your maximum leg force when cycling.

I've done a bit of a search and I can't find it. I was wondering whether you'd bookmarked it, or whether I was just imagining things.

 

[The_Break]

Hi Johan

 

All fair, all fair! Guess we could argue till NASA publishes a white paper on chains and then some.

 

Ok, guess we should all be at peace here and save our energy for the races then. Sorry for any offense I have caused then.

 

As for me keeping anon, it is more for political reasons regarding clubs and sponsorships than anything else. I am a bit hot-wired so I know when to keep things under wraps. My mouth has got me into trouble before. I will do my best to only say things I would say should I post under my name.

 

All good?