FluffyChicken":wl4b8qq3 said:
DX etc was also SS and SGS, not till lower down the range did GS appear, even SS was still available
Of course it was the 6/7speed era (MTB, Road was already at 8sp) and the range of a 6speed wouldn't need such a large chain wrap.
In fact, at least in 1991, 105 (RD-1055) a commonly used mech had the same spec as the XT Short cage
Suntour of course in their McroDrive range made short cages, I forget the bolt to bolt length.
Things changed a bit over the years eg M730 was only available in GS and SGS as was the comparable DX hence the use of road versions. The short cage SS versions of XT etc which came later weren't that common which is why they aren't seen all that often. Likewise the M950 SS is a pretty rare beast too
The SS caged mtb derailleurs I've played with all appear the same length as the short cage SS road versions (which makes sense if you look at a lot of Shimano codes), and most people who talk about short cage derailleurs are refferring to GS ones rather than true SS versions.