I have a bike with vertical dropouts, and i want to calculate the proper gear ratio/chain link ammount to get good tension. i have found a couple calculators (below). my question is, what is the ideal chain stretch? one of these sites assumes there is a half inch of chain stretch.

http://eehouse.org/fixin/formfmu.php...ey=Stay_length

http://www.machinehead-software.co.u...engthcalc.html