VeloNews magazine will bring you inside the sport of bike racing, with exclusive features, analysis, expert training advice, unbiased gear reviews and the absolute best cycling photography. Dear Lennard, Great article on drivetrain friction. I never considered the difference in torque on chain tension. But I do want to point out one thing. While you correctly pointed out that smaller cog and chainring combinations have greater chain articulation, it is also true that the number of chain links that experience this is smaller. For an example: A 53-tooth chainring has about 10% more teeth than a 48-tooth chainring. During one full cycle of the crank, 53 links of the chain are articulated at the top of the chainring. (53 x 8 for the whole drive train.) Now for that same cycle, 48 links are articulated for a 48-tooth chainring. So about 10% less links are articulated by about 10% more in chain articulation. That should turn out to be a wash. I have pulled apart quite a few SRAM’s pulleys, and their upper pulleys generally have a lot of friction in them. Unfortunately, they generally can not be replaced, as they are custom and not a standard design. Also, the 1X drivetrains use signif...