Originally Posted by vjp
The headtube on the bike is 143mm and the steerer tube is 212mm to the bottom of the threads which leaves 69mm. I am not sure what the stack height of threadless headsets are, any idea?
vjp
They are similar to threaded headsets, usually in the range of 30 mm to 40 mm. Chris King's can be set up as short as 28 mm.
Headset longevity is limited by brinelling of the races. How does threadless help in this regard?
The newer design cartridge bearing headsets aren't subject to brinneling and their "races" are part of the bearing, not the cups. The cups and crown race are just support elements. They never see the actual bearing balls.
A worn-out cartridge bearing headset can be restored to like-new by replacing the bearings. The cups and crown race don't have to be changed.