Originally Posted by
Salamandrine
I'd conjecture the main reason for rolling threads would be to make the threaded portion of the steer tube slightly stronger in case someone adjusts their quill stem too high. Of course that's not supposed to happen - but it does. A second possible reason might be because it's faster. I'm sure the tooling cost plays into it as well.
So that might be in play for some of those replacement forks you can find (even if the fork lists as being CrMo, it might just be the blades) where they only want to make one size replacement for so they make a 250 mm steerer with 100mm+ of threads. I have a couple of those untrimmed as I'm a bigger fella that rides tall head tubes.