I have two theories as to why my chain sag correction factor is not precisely equal to my sled weight, which I estimate to be about 25 lbs.

Theory 1: We aren’t calculating chain sag correctly.

Theory 2: Chain sag adds a variable amount of length based upon the angle of the two chains, the lengths of the two chains, and the weight of the sled. Rotational radius subtracts a fixed amount of length whereas chain tolerance adds a variable amount of length based upon the length of the chain. I suspect that as rotational radius and chain tolerance values are adjusted, they may be compensating for a low chain sag (a reduction in error is an improvement, no matter where you get it). So maybe these values are “overcompensated” and then the chain sag gets “under-compensated” to even it out. If I don’t allow for rotational radius or chainsag to get adjusted, the chain sag correction lands at around 25 (lbs).