The 25 lb.ft. torque given in General Data page GD9 was for earlier machines using steel spindle caps. Newer spindle caps were made of alloy and they are prone to fracturing under that much torque. 15 lb.ft. is said to be more than sufficient for stud nuts holding alloy caps.
See "Fractured Axle Clamp" thread on TriumphRat.net for a discussion of this issue.
