These are the cranks that took Shimano away from square taper cranks and into spline interfaces. However, the spline interface was short and as a consequence not particularly robust. Shimano's next versions of their MTB splined interface cranks used about the twice the contact area. The cranks also used a proprietary BCD for the chain rings. Shimano has a habit of doing this with its XTR cranks, but thankfully, the M952 cranks have a removable spider. Use the spider from a set of XT or LX cranks to convert to 104/64mm BCD. Middleburn also make a replacement spider.