is the claim of track slack (sloppy chain tension) being more efficient broscience?
this claims higher chain tension more efficient
>Experimental results indicated that the efficiency of the chain drive varied as a function of chain tension. It was found that the efficiency varied linearly with the reciprocal of the average chain tension with the highest efficiencies occurring at high chain tensions and lowest at low chain tensions. For example, the highest efficiency measured in the study, 98.6%, was measured at a chain tension of 305 N and the lowest, 80.9%, at 76.2 N.http://www.ihpva.org/HParchive/PDF/hp50-2000.pdfsheldon brown says it should be as tight as it can be without binding
the top track cyclists like pic related don't seem to have a dramatic amount of slack in the chain
on my fixed gear bike i ended up with a bit less than the recommended 1/2" up/down movement when measured but i don't think it's a limit that's set in stone and my bike has a perfectly centered CNC chainring (narrow-wide), a 3/32" phil wood cog and kmc e1 ept chain so it's not like i need much slack to compensate for tolerances and avoid binding. my phil wood cog made a lot of noise as if i had playing cards in the spokes when i first tried spinning the drivetrain with loose chain tension. my intuition says that with less chain tension there will be more friction caused by the chain bouncing around more from vibrations on a road surface.
