Abstract
Improvements to maintenance have reduced the incidence of wheel-fixing defects but problems are still occurring due to uncertainty about tightening nuts. The balance between sufficient tightening to absorb in-service load fluctuations and over-tightening beyond the stud's yield point is discussed. The results of a number of tests carried out to study torque/tension relationships are reported. Recommended loads for standard nuts are suggested. The stud tension required to keep a spigot wheel clamped firmly is discussed. It is concluded that there is arelatively small margin of safety. Varying results are reported in identifying the tightnening torque required to give the appropriate clamp force