I go by the rider's manual, which states the proper amount of slack, measured whilst the bike is on the kickstand. I run it at the higher (looser) number in the manual, maybe even a tad looser. It does tighten when you sit on the bike, but I would hope the measurement in the rider's manual with the bike on the sidestand accounts for this. I'm thinking it does, as I think the upper range is 1.5 inches? So, sitting on the bike may compress it 0.5 inch, therefore agreeing with Brit's measurements.