How do you measure the play in the chain? With the bike on the swing-arm stand, I rotate the wheel to the point where the chain feels the tightest. I place a small framing square on the bottom of the swing arm with the chain just behind it. Then I press the chain down with about 5 pounds of force and I make a pencil mark on the framing square where the center pin of the closest chain link is. I then push the chain back up towards the swing arm and make another mark on the framing square next to the nearest link's pin. I take the chain slack to be the distance between the two marks that I've made on the framing square. My question is this: should I be measuring from the link pins or from the top/bottom of the links themselves?