Originally Posted by
BarracksSi
Also, some fork manufacturers, like Easton, say to put one spacer on top so that the stem isn't stressing the very tip of the carbon steerer tube.
Easton's fork instructions specify a full 8mm above the stem, and they provide a 10mm spacer with their forks to go on top, just in case you don't have one.
I've always wondered why 8mm...why not 3-4 with a 5mm spacer on top? Do those extra mms make that big of a difference in the stresses on the steerer tube?