What is in a chain(full Q&A)

[paulvs]

From the web....

 

 

 

Letter to Sram

Hi: I have been a user of your chains for some time on a variety of

bikes equipped with Shimano and Campag and 7, 8 or 9 speed, and in the

interests of extending the life of cassettes/sprockets and chains I

have recently begun to study a little more closely the various models

of chains you produce.

I note from your website that a number of models are described

as "step riveted" whilst others are "cross-step riveted" or

"cylindrical". I can see that the latter pertains to the new hollow pin

chains, but I wonder if there is any difference in strength/longevity

between these various joining methods?

What are the relative merits of say the PC-48 and the PC-58

and PC-68? As you go up this product ladder there is an increasing

amount of nickel plating, but I assume this applies only to the side

plates and that the pins and rollers of these three chains are

identical - is this correct? If so, is it reasonable to argue that, so

long as the chain is kept lubricated against corrosion, the PC-48 will

perform as well as the PC-58/68?

When it comes to the degree to which a chain can be used

before it becomes dangerously weak (and leaving aside any issues of

accelerating sprocket wear) what would you say the maximum amount of

acceptable wear, measured in lengthening of the chain pitch, would be?

Also, although you suggest in your FAQ using

de-greasers/cleaning solvents, you advise against removing the chain

and leaving it to sit in such degreasers - why is this? I ask this

because I am interested in learning how best to clean and lubricate the

chain for long life. It seems to me that many de-greasers do a good job

of cleaning off the external parts of the chain, but I wonder whether

when it comes to the internals, all they do is dilute the mixture of

oil and metal that gets inside the rollers?

I hope you can educate me on these questions.

 

Peter Faulks

Reply

Dear Peter,

 

My name is Mark Pippin. I am the product manager for chains at

SRAM Corp. I was forward your e-mail a couple of weeks ago. Sorry for

not getting back to you earlier, I have been on the road. Let's see if

we can answer some of your questions.

Re: Riveting Process The goal of a riveting process is to

deform the metal rivet to prevent the opening of the chains side plates

under load. The ways that you increase the strength of the chain

riveting process is by A) increasing the displaced amount of metal of

the rivets and B)the thickness of the outer plate. Re: Rivet Types: At

SRAM we use 5 different levels of riveting. 1)Standard Rolled Rivet:

The fastest, cheapest, and least strong riveting. What happens here is

that the chain is pulled thru a set of round dies that deform the

rivets. This is used on single speed non-derailleur bikes. It also has

the tallest rivets, and receives the least amount of side loading. So

it's weaker, but in it's usage pretty darn strong. 2)Step Rolled

Rivets: This is also a rolled rivet, but much more precision and

slightly slower in processing speed. This type of rivet is

shorter/flatter and is used on our basic derailleur chains. It's has

about 50% more Push Pin Power than the Standard Rolled Rivet process.

It's about 1500NM's (sic). The step riveting is moving more material

than the standard roll riveting. 3)Cross Step Rolled/Stamped Rivets: Is

a double riveting process that rolls the step rivet, then hits it again

to displace more material. It's one of our strongest types of riveting

at over 2000NM's. With all the above methods of riveting, the hole in

the side of the plate is straight with no draft/radius. So the

deformation of the rivet flows over the outside of the link itself.

4)Cylindrical Riveting (Hollow Pin type): With this type of riveting,

the material is displaced into a chamfered/tapered hole and the

thickness of the plate plays an important roll of the Push Pin Power.

For example, our PC89R Hollow Pin has a PP Power of 1500NM's, while our

PC99 Hollow Pin has one of 2000NM's. The difference is that the 89R

uses .90mm plates, while our 99 uses 1.0mm plates. Cylindrical riveting

is much slower since it must strike every rivet individually. 5

Round/Orbital Riveting: This is our strongest rivet, but is only used

for Power Links. It is pretty tall and displaces a lot of material, but

is not really a good method for the complete chain. Chains must be cut

a couple times in their lives, once to obtain the correct length and a

second time to be adjusted to the bike. This rivet is almost un-open

able and would cause problems for both us on the production side and

also for the consumer. We use it on our Powerlink since this rivet will

never be opened.

Re: Durability of a rivet. In general, there is no major

difference in the rivet method vs. longevity. Yes, you could argue that

a larger displacement of materials would offer more longevity, but only

slightly. Durability of a chain comes from the hardness of the pins and

of the inner links that ride on them. We are doing a research project

with the University of Coimbra on what causes chain stretch. Chains

really don't stretch, they are just wearing out. Yes, in extreme cases

the material of the outer and inner link could deform and stretch, but

this is rare. What is happening is that the rivet pins and the inner

links are wearing.

Re: Differences in Models. In many cases, what is changing is

the plating, but the underlying materials are the same. So, you are

correct. The only caveat to that is the all the materials thickness and

process (heat treatments) are [not] the same. Please note that we do

not use the same links and then just change the color at will. If we

are going to do a nickel outer link, we would have to change the hole

size for the rivets to compensate for the nickel plating. Yes a chain

is that precise.

Re: Replacement. This is a tricky one. You could argue that

any change in length above 12.7mm pitch, you should change [the chain].

You need to remember that there are 114-116 links times x amount of

wear. It does not take much to cause a chain to get too long and start

to effect the rest of your drive train. I would say that most of the

chain length testers are pretty correct to use for a guide. Sorry that

I cannot offer a more precise answer on that one.

Re: Cleaning of chains. The reason why we do not suggest

leaving chains in a solvent tank is because it takes out all the lube

between the pin and the inner plates. If we could make sure that people

would then use a liquefied grease, then let it cool, we might suggest

that people clean chains in a solvent tank. This is how we do it at our

factory. We recommend that the user use cleaners that only attack the

outer surfaces of the chain to take away the dirt and grime then

re-lube. I personally have only used a rag to clean my chains for years

and stay away from solvent tanks and jet washers. It's cheaper to

replace a 10-15 dollar chain than it is to replace a Ti cog set and an

XTR chainring set!

I hope that this helps you better understand chains and SRAM

chains in particular. If you have any more questions, feel free to ask.

 

Best Regards,

 

Mark Pippin SRAM Product Management

 

 

[Face Plant]

interesting read

[Christopher Brunsdon]

Should be a sticky

[Fleming]

Anyone else wonder why a SRAM employee talks about maintaining chains and then goes on to say its cheaper to replace the chain than a Ti cassette and "XTR" Chainrings? 

[crasher]

Yes I wondered that maybe its just because of the price of the XTR chainrings that he used it to make his point hit home

 

Good read and nice to get a reply like that from a manufacturer 

[BrendonMyb]

very imformative

 

agreed crasher. Is refreshing to get some valuable feedback from suppliers like that & give a little inside info

[Johan Bornman]

Intersting to read about the different riveting methods.

 

I agree with him that solvents remove the oil (that's why we put them in that in the first place) but disagree that it is difficult to replace the oil inside.

 

Capillary action ensures that everything other than the thickest oil penetrates every single cavity inside the chain within four or five revolutions of the crank.

 

I think his solvent explanation is moot.

 

 

[jugheaddave]

interesting read!!!

 

I agree with JB

 

[Cassie]

Slightly off topic: I am a regular user of parafin to clean my chain with, simply because it is so effective at cleaning. But Now I've been told that parafin leaves behind a residue film layer that the next round of lube application would not adhere to the chain surface properly...is this correct? also that i should rather use turps!!??? because no residual film will be left behind....

 

Not so sure about that? Any comments?

 

[Christopher Brunsdon]

I thought turps would leave behind the film and not parafin. I use benzine too clean my chain.

[jugheaddave]

 

Slightly off topic: I am a regular user of parafin to clean my chain with' date=' simply because it is so effective at cleaning. But Now I've been told that parafin leaves behind a residue film layer that the next round of lube application would not adhere to the chain surface properly...is this correct? also that i should rather use turps!!??? because no residual film will be left behind....

 

Not so sure about that? Any comments?

 

[/quote']

 

I am no expert here, but what I sometimes do (if I am feeling really keen and motivated) I will wash my chain with turps/diesel/paraffin ect, then rinse it in a little prepsol, and then spray/rinse it with water.

Leave it to dry over night, then apply lube (no wax kind) then pedal the chain around for a few minutes, then wipe of the extra lube if If need to.

 

This method (although time consuming) Seems to give great results.

 

What u think JB??

 

[Guest Agteros]

 

Why remove one lubricant/wax (cheap) and replace with another one (expensive?)

Agteros2010-01-16 00:30:42

[Johan Bornman]

Cassie, Chris and Dave - all in one.

 

This is religion but I'll tread carefully.

 

There is seldom a need to wash a chain in a petrochemical solvent like benzine, petrol, diesel, jet fuel or rocket afterburner fluid.

 

If the chain is oiled with regular oil - bike-specific or just motor oil, and regularly cleaned, then a soapy solution is good enough. Soapy stuff like Prepsol or Team Green (or whatever) is so much more pleasant to work with and much kinder to the environment.

 

If you remove the chain (does anyone still NOT use quick links?) and shake it in a container with Prepsol and then rinse it in water, it comes out clean.

 

A light application of a half drop of oil on every second roller puts enough oil on there to lubricate the chain. No need to put oil on the sideplates.

 

Benzyne is a known carcinogenic and it is readily absorbed into the body through the skin. It has no place in the household.

 

 

[Jaco Steyn]

Johan,

 

You must just take care not to confuse Benzine with Benzene. As taken from Wikipedia: "Benzine should not be confused with benzene. Benzine is a mixture of alkanes, e.g., pentane, hexane, and heptane, whereas benzene is a cyclic, aromatic hydrocarbon, C₆H₆. Likewise, petroleum ether should not be confused with the class of organic compounds called ethers, which contain the R-O-R functional group."

More info: http://en.wikipedia.org/wiki/Petroleum_ether

[Johan Bornman]

Thanks Steynja

I was actually expecting this post and I'm glad you spotted it. The stuff they sell in PnP and which I presume is what one of the posters uses to clean his chain. The bottle says BenzYne - with a Y. Which one of the two compounds will that be?  The good or the bad?

[Jaco Steyn]

Thanks Steynja

I was actually expecting this post and I'm glad you spotted it. The stuff they sell in PnP and which I presume is what one of the posters uses to clean his chain. The bottle says BenzYne - with a Y. Which one of the two compounds will that be?  The good or the bad?

 

Johan, that will be the "good" stuff. It is actually quite difficult to get hold of pure or even technical grade Benzene (C₆H₆). I work at Sasol in a laboratory, and we need to get special permission to keep Benzene in our lab. Actually, currently we need quite a large volume of +98% pure benzene for one of our projects, and it is easier (lot less hassle and paperwork) for us to obtain a Benzene rich (?50%) stream from Sasol in Secunda and distill it to our required purity. Getting hold of large quantities of pure potable Ethanol is even worse!

steynja2010-01-16 07:33:49