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My understanding is a little different. The difference between the two sizes (three if you count the one that fit the proflex bikes exactly without spacers) is that on the long head tube version the shock assembly and the distace between the mounting bolts on the legs are both longer by an inch and a half or so. That's why leg sets come in the long and short version. The shock is actually the same unit but the aluminum piece that mounts it into fork on the bottom side is longer on the long version. It is true that I could use this long version fork but it would require me to use about 2 inches of spacers and would result in my handelbars moving from where I like them (I can't just flip my stem upside down because it would then interfear witht he top of the fork when it's fully compressed.)I can get the aluminum shock end from noleen (i'll probably be sending it in for a rebuild anyway), but i haven't yet found a set of legs for a reasonable price.