New style XT hubs are a throwback as far as quality. Oversized aluminum axles, 3/16 ball bearings in a retainer (wtf shimano?). Have seen several severely locked up hubs where the bolt that holds the freehub body onto the hub shell unscrewed itself. These hubs are no longer used in loaded touring situations for example. Many builders in that field go back to LX hubs (FH-T660), which is basically a revamped Tiagra hub with better seals. It does have the reliable steel axle and 1/4 inch bearings.