Originally Posted by
erader
i would think that GS would be more common then SGS for off the rack XTR.
Again, determined more by number of chainrings, so I'd bet SGS is more common for any grade of model since triple chainrings are just more common for mountain bikes.
Just measured a little more closely, and (edit) 87 or 88mm looks right. So, looks like you've got yourself an SGS. It will work on a 1x9 system just fine. Actually, the MTB SGS RD is the most versatile and will work on most any bike, it's just unnecessary on many.