2015 Campagnolo Super Record Shifting Compared to Shim/Sram

[XCProMD]

Factory lubricant is very similar to 75 gearbox oil. A good if time consuming practice is to put the chain in hot water with degreaser, then dry and dip it in very hot (100C) gearbox oil.

[arizonahalfnhalf]

It's not the chain

[XCProMD]

That's also true.

[Calnago]

Factory grease is thick and mostly just to preserve the chain so it doesn't rust if it's stored for a long time before use. I always try to get as much of it off as possible before installing it and do put the brand new chain in a pan with some simple green degreaser and heat it up then rinse thoroughly before installing and fine tuning. Once all that is done the final step is to apply the lube you like, in my case that's Duomonde Tech Lite.

[dmp]

Agree with Calnago- Dumonde Tech LIte is great. I think you may need to apply it more often that some other lubricants, but its the best I've ever used. As he notes, don't clean the chain with solvents but rather dishwashing detergent between applications. You will hear a difference when the chain needs relubricating.

[boysa]

If you find you need to apply it often, switch to the regular version (not "lite"). I find it lasts about twice as long.

[XCProMD]

Well, about chain lubricants:

There are two main design challenges in today's chains as they are getting narrower to accommodate more cogs in approximately the same space: There are two main things to make narrower: the roller/bushing system ( today's chains are called "bushingless" but that only means they no longer have the tight fit independent bushings of old) and the side plates.

The plate problem is a "simple" yield strength issue. To make the chain last the same as before, i.e not stretching/yielding too much over time, we need a steel with a higher yield strength.

How do you do a steel with a higher yield strength? There are two ways: 1-quenching 2-more alloying . A combination of both is the most normal thing. But we can make a rough difference between:

1 -DQ/RQ/DQT/RQT carbon steels, with just the minimum amount of alloying to allow a very extreme and accurate quenching (Jomini Test, i.e http://www.tf.uni-kiel.de/matwis/amat/iss/kap_9/illustr/i9_2_3.html ) which can have a chemical composition very similar to this:

Capture.PNG (8.71 KiB) Viewed 1553 times

Which results in a low carbon equivalent CEV of 0,62 so would even be weldable with regular consumables. Furthermore, this low alloy quenching process results in a toughness of 37J at-40C even when this particular steel has a yield strength of 1350MPa. This kind of steels were developed in Europe since the 1970's and are widely used now for structural applications (covered by the EN 1993-3) like crane booms. In USA is is very difficult still to see something above 700 MPa (110KSi).

2 -Tool and bearing steels, in which the alloying content is much higher, allowing for quenching processes that are easier to do (and don't require the vast investments and R&D costs of the quenching lines for Q steels). It is this alloying content that rises yield stregt at the expense of lowering the toughness and the fatigue properties of the steel.

Sorry for the pic being in Italian but I think it's easy to understand. The red line is where Q/QT steels move along. The grey dotted line is where tool steels are. Meaning that in order to increase hardness or strength, toughness is further compromised.

Bearing steels are roughly a variety of tool steels that are much cleaner as they are manufactured by Electroslag Remelting (ESR) http://www.aubertduval.com/forging/induction-melting.html. And this is important as we will see later because in bearings (and bushings and transmission mechanisms) we have to deal contact stresses that create contact fatigue.

Bottom line: to get our chain plates thin and strong, i.e. have the same wear rate with thinner plates, we can either go for low alloyed, clean Q(T) carbon steels or for tool steels. Or something in between if you can make/order your own steel grade

Then we have the bushing part. And this is more complicated as this is not just a part submitted to tension as the plates are. There are a lot more things going on here. Welcome to contact mechanics .

Capture1.PNG (2.75 KiB) Viewed 1548 times

This is the main equation you need to calculate a mechanism like the roller of a chain pressing against the cogs on its external diameter and against the plate flanges in the internal one.

The funny greek letter with a tiny H is called Hertzian pressure after a smart German lad. F is the force on the cylinder (the chain roller in our case), E is the elastic or Young modulus (in our case steel, and all steels have roughly the same E, between 207 and 215 GPa), L is the width of the roller and D is the diameter of our little roller.

Bottom line: you want your roller and everything it may press against to be made of a steel with a yield strength that is higher that the result of this equation for our specific case.

But there is a catch here : Our chain is cycling around the driveline, once and again, rollers prssing now against the cog teeth, then on the chainring teeth, rinse and repeat, one helluva zillion times. In a static mechanism you'd only need to care about the above equation, but with that chain spinning around you have a more complex problem called "contact fatigue".

And contact fatigue not only depends on Hertzian pressure, but also on

-Number of cycles.
-Temperature.
-Lubrication.
-Surface roughness
-Fatigue characteristics of the material (that are dependant on surface roughness and cleanliness and homogeneity)
-Yield Strength of the materials

Very complex stuff with many interdependent factors. For instance, cleanliness and homogeneity of the material influence not only fatigue characteristics but also Yield streght. As we've seen above one way of having a stronger steel is adding alloys, but then fatigue becomes an issue and you will probably need to go for an ESR steel... or a Q(T) type that has been manufactured under a Vacuum Tank Degassing process from blast furnace iron.

The thing is that when we have a dynamic contact pressure, lubrication appears as another factor to consider. In a static contact pressure, the maximum stress happens below the surface and that is where the material will start to yield, compressing. Eventually, if the pressure is enough the material will develop a crack starting in that area.Lubrication wouldn't help or change anything here.

But contact fatigue happens at a much lower pressure than the maximum permissible static contact pressure. Furthermore, in most cases there is a sliding wear mechanism working against our nicely designed and manufactured contact surfaces. Here lubrication makes a lot of sense: On one had we can dramatically reduce sliding wear. On the other the right lubricant (one that is able to withstand the contact pressure of the mechanism)can distribute the load to a larger area, further reducing pressure.

And that is the key of the lubrication of a chain. What you want between your nice little roller and your plate flanges, so bwtween 4 and 7 in this picture

is nothing else than a lubricant that withstands the pressure there, which is the highest in all the mechanism as you have a small diameter and very little contact width.

You don't want the oil they sell you for bicycle chain maintenance there. You want the real stuff. Thick, Well Formulated, Heavy Transmission Goo. And you want it to last forever because there is not easy way to get your TWFHTG in there. It is better if Campagnolo, SRAM, Shimano and all those blokes that make bicycle chains you can smash trying your next KOM do it for you when they assembly the thing together.

So actually you don't want it out of there either. Because it will take you a while to put the right stuff in there and if you happen to share a kitchen with someone that someone will probably hate you forever if he/she surprises you heating gearbox oil and dipping your squeaky-surgically pristine chain on it. Which is the only procedure that will give you a chance of lubricating the bushing properly.

So: Be careful when you clean your chain. Clean the crap outside, but don't overcook it and attack the inner lubricant. Part of the formulation of that lubricant is intended to keep it safe from allowing debris in tightly assembled areas, and to prevent it from washing away. And that is supernice.

As far as you have the real TWFHTG deal in the bushing, you can use whatever you fancy to keep the externals shiny and quiet. My advice would be spending as little as possible and clean it fairly often, because the most important thing there is keeping away hard particles that can add to the fatigue contact pressure of the external surface of the roller. You don't want silicon, for example, between the roller and the cogs.

There is another funny thing about the effect of lubrication on contact fatigue. Depending on the nature (viscosity above all) of the lubricant and the surface roughness of the parts in contact, the lubricant can help developing cracks. Yes. Help.

Obviously you have your rollers nicely finished, the same not always applies to your stamped cogs

that will have a nice sheared edge and an uglier fracture edge.

It is not a big deal because that crack developing effect is self-healing. At some point the relation between viscosity and roughness is such that the lubricant no longer develops the crack. So the thing is not going to break in two, but you managed to go from a slow sliding wear to a much more aggressive cutting siding mechanism

So wear will increase a lot. Specially on the stamped cogs. Mmmm, did I said stamped? SRAM's top of the line cassette clusters are machined . But out of very heavily alloyed tool steel

It is very interesting to analyze the composition, crystallographic structure and finishing of chains and cogs from different manufacturers. The results mesh very well with the eagerness each of them has historically showed in increasing the number of gears.

[BlackMadone]

When downshifting on my 2015 Record (moving to larger cogs) I can get this when multi shifting 3 or 4 down. It shifts but is then noisy, I have to slightly press on the paddle to get it to move completely or shift up with the thumb paddle to correct. On the way up the thumbs shifter is lighting fast.

Also when I'm in small/small 34/11 it's noisy. I have checked the front and rear derailleurs and its noisiest when the FD is in the middle position but with no friction.