I measure it near the front of the rear tire which is about half way between the sprockets with either a tape measure standing up from the floor, or a ruler pressed against the tire in a vertical orientation. Regarding the amount of force, I press about hard enough to bruise a fresh tomato (how’s that for a reference!?). You can press harder, but the measurement won’t increase by a significant amount.
I measure the maximum amount of deflection at the top of the chain from pressing down on it to pressing up on it.
Notice the link to similar threads below this thread. They may explain it better there.
2015 DL650XT w/ factory Suzuki/Motech side cases and engine guard.
First farkle - Motech center stand
Augustus Wind Deflectors
Fat, foamy grips
Givi AirFlow windscreen
Go-Cruise throttle lock
JD Astar 1260 lumen LED tail light bulb
Suzuki (SW Motech) Top Case
Hyde Racing skid plate
Adventuretech kickstand foot, fork brace, fender raising kit, and peg lowering kit.
Zita 26mm up / 20mm back risers
Sit and Fly Seat Net
So God created man in His own image; in the image of God He created him; male and female He created them. Genesis 1:27