Originally Posted by
Mansram01
I don't think this has much to do with chain slack since the rear derailleur takes up the tension when you're on a small cog and releases that tension when you're on a large cog. This has more to do with the energy required to turn (mash) that cog over. I'm sure someone else can explain it better.
yes, slack was probably the wrong word to use. I guess I mean the chain is shorter when on a higher (larger rear cog) gear.