Originally Posted by
Kontact
I certainly did not say that wax isn't a lubricant. I think you are confusing my reference to your statement about completely unlubricated chains still being efficient.
Okay, maybe I’ll grant you that. You said that certain waxes and oils weren’t
good lubricants. You are wrong but anyway…
But what was being discussed is that lubricants are there to prevent metal on metal wear. Wax does that for long periods, which is why the chain doesn't squeak. Wax is a low drag lubricant - probably because it is mostly solid and completely untacky, yet still provides sufficient lubrication where the force is applied. Efficient lubricants are those that prevent wear with a minimum of their own drag.
Chains are polished metal-on-metal surfaces under relatively light loads. The only reason they squeak is because the polished surface becomes less polished due to oxidation. Drag of the lubricant really has very little to do with a lubricant’s efficiency, especially under such light loads as bicycles put on the chain. The maximum load that is put on the bicycle chain is the weight of the rider. That’s also the maximum load that is put on the metal on metal contact.
Again, there is heat produced - as you admit. That heat doesn't have to get the whole chain to increase in temperature for a very confined area to get briefly warm. And there are two spots on the chain that pivot under load which could account for the majority of that heat. Just as you can hold a pipe that is being tig welded on the other end, a piece of metal doesn't have to heat evenly.
I’ll admit to a very, very small amount of heat produced by friction. 0.5% of whatever is put into the chain is lost to heat. As elcruxio has pointed out, they’re just not enough heat available…even highly localized…to do what you want it to do. And, yes, you can have localized heating of a piece of metal but that heating works in both directions. Heat put into one place on a piece of metal is quickly distributed to the part of the metal that is u.n. heated
and the overall temperature of the metal rises. Heat put into one end of a piece of metal is going to eventually end up in the other end. To torture this metaphor further, if you are to apply the heat of that weld to only one end of a piece of metal for a very long time, the whole bar will eventually be hot even with radiative cooling. A better analogy using welding would be a series of welds moving up the piece of metal. The whole piece is going to quickly get hot. At 90 rpm of the cranks, the each link of the chain is passing the point of highest pressure 90 times a minute. If you had sufficient heat to melt the wax, you could feel it at the end of the ride. Radiative cooling happens but not that quickly.
I know what a chain looks like. The points I've been referring to are where the pins run through the inner links. The surface area is so small and the pressure so great that there is NO WAY solid wax forms a barrier that lasts for 200 hours or more under load.
The pressure really isn’t all that great. The wax inside the rollers is somewhat elastic and the void is filled. You don’t need, nor have, much wax on the pins to provide lubrication. Under even the light pressure of a bicycle chain, I’d suspect that the layer of lubrication is, at best, microns thick. You wouldn’t need much wax touching the pin to drag some back into the space where it has been pushed out of.
Rain has nothing to do with anything. I never mentioned rain at all. Waxed chains ridden in dry, cool conditions lose pivot wax until they squeak. According to you this can't be happening.
You completely missed the point on rain. If the wax were melting like you suggest, the wax should fill back into the void and should keep the chain from squeaking after rain and reapplication after rain wouldn’t be necessary. In fact, given the amount of wax that is held up in the rollers of a chain, if wax melted like you suggest, you would likely never need to rewax a chain.
Think about what you are suggesting for a minute. The wax gets pushed out of the pin/plate interface when the chain goes over the gears. A small amount of wax gets melted and flows back into the space. The amount of wax needed would be on the order of micrograms and you are likely to have, perhaps a gram of wax available. That’s a million times what is needed so it should never go away.
Just to be clear, that’s your scenario, not mine.
But rain definitely shortens the life of a waxing. Why? Because water washes out the wax when it liquifies. Since you don't ride immersion waxed chains in a rainy climate, you wouldn't know anything about what you're claiming.
First, don’t pull that “you don’t ride where I ride” crap. I’m not unfamiliar with rain riding. I don’t just ride when it is dry nor do I ride where it never rains. Solution waxing uses the same ideas as immersion waxing does with similar results and similar pitfalls…no matter what you may think. Second, I spent a significant amount of my life studying and working with chemicals. I know a whole lot about their properties and how they act and what they do.
Now on to wax and water. Have you ever dripped wax onto water? It solidifies almost immediately. And the thinner the layer of wax, the faster it is going to solidify. You might be able to get wax to melt if the water is over the melting point of the wax but that’s not a water temperature you are likely to experience while riding a bicycle. If…and that is a very, very, very large “if”…the wax melted at all on the chain while riding, water is going to cool that wax and metal quickly below the melt point and solidify the wax. The wax wouldn’t wash off in any way. Wax won’t wash off of anything in water. Even if the water is over 150°F, it is difficult to get wax to melt and move.
By the way, oil is far more likely to float off a surface when exposed to water than wax ever would. I have long advocated that just because wax squeaks after rain and needs to be reapplied, oil doesn’t perform any better and the liquid nature of oil just masks the oxidation problem rather than solve it. Oil should be refreshed after just as wax does.
I would address your assertions that gravity is a bigger force than surface tension for oils, but why bother?
Oh, by all means, explain surface tension of nonpolar compounds to me. I need something to chuckle at. For that matter, how about explaining to me how surface tension of a polar substance like water is greater than gravity while you are at it.