'''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
Measure the length of the frame's head tube end to end. Then measure the overall length from the fork's crown race to the top of the headset's lock nut. If there are any spacers between the headset's top race and the locknut, measure them too.
Stack Height = Overall Length - (headtube length + height of any spacers).