Hi all, as we rapidly approach the 20th page of chasing our tails, i'll make an attempt - admittedly most likely in vain - to put this topic to rest (why does this feel like i'm putting my own neck in the noose? ...i ask myself). OK here goes:
Having enjoyed following this thread, the most prominent single argument from each camp which i noticed were as follows:
THE 'DRY' CAMP: "greasing the taper means the crank will be pushed too far onto the taper causing permanent damage to the cranks [supposedly leading to cracked cranks, loose cranks, creaking cranks etc]". This my friends is a complete and utter myth. Torque values exist and must be respected. Torque values of screwed fasteners are specifically chosen to achieve two aims, firstly to affect a sufficiently secure and lasting fixture and secondly to avoid permanent damage of the components which are subjected to the force resulting from the applied torque (i.e. not exceed the elastic limit of the materials involved). This means that if you assemble the thing PROPERLY you are not going to damage the cranks or the taper. Aluminium is not cheese. greased tapers are not going to magically change the elastic limit of the materials or the force applied by the tightened crank bolt. Greasing the tapers will not cause damage to a PROPERLY assembled bicycle and if anyone wants to suggest otherwise i respectfully request them to supply irrefutable evidence.
Just a little footnote: Many people (i'd venture to say almost everyone) who do not use a torque wrench over - rather than under - tighten their fastenings and do so by a considerable degree. I have seen this time and time again. Many folks who use a torque wrench for the first time are amazed at how soon/easily the CORRECT torque is reached.
THE 'GREASE' CAMP: "greasing the taper protects against corrosion and facilitates easier disassembly". This is 100% correct and is good engineering practice for a tapered and contoured/keyed shaft including but not limited to bicycles (BTW we are not talking about lathes so let's not start that again - completely different application and principle of the shaft's drive transmission). Furthermore, greasing the taper assists in preventing binding and material pick-up therefore leading to correct and full seating of the components.
Another little footnote: By 'grease' you can, in the case of a bicycle, consider anything which provides both lubricative and anticorrosive properties (copperslip, LM, molybdenum, graphite, virtually any decent grease or oil SP, HP, EP, whatever).
I probably sound biased because i do lightly grease my tapers (above statements is why i do!) but to show [attempted
] fairness to both camps i offer the following:
A bicycle is, from an engineering standpoint, a very simple machine. It's components are not subjected to extreme
temperatures, pressures, vibrations, torques or forces. Hence the real answer to our shared dilemma is that it really doesn't matter very much. If it did matter the answer would be gospal and there would be 1 page of consensus instead of 20 pages of arguing and the manufacturers of bike parts would all be singing the same tune. Chainline differences (if any) caused by dry or greased fitment are so miniscule as not to matter one iota in practice.
So my dear friends i wish to say how much i've enjoyed this discussion and now that i have the noose around my neck, who will be first to step forward and kick the wobbly chair from under me?