Hey, I just got a new chain and put it on my bike.. I think it is way to tight, but I was told from the place I bought it that 10mm slack is enough? Normally I measure my chain by pushing it up and down and measuring the slack on the chain - this chain is maybe 10mm... I usually hold my chain between 20-30mm slack when I ride.
Also, how do most people define "slack"? Is it how much play is in the chain when you force it up and then down and measure the distance?