Worn Hub Diameters

Over the years the threads of the lock nut and hub wear, particularly if the wheel is run loose and the serrations of the hub and wheel shell fret, ultimately becoming dangerous.

The table below gives details for Rudge-Whitworth wheels from No.5 introduced in 1908 to the more well known types 42 to 120 which were introduced in 1912. The earlier ones were used with wooden spoked wheels as seen in the hub cross section opposite.

 If the lock nut is worn enough to admit a plug of the diameter in column A it should be replaced. If the hub thread is worn enough to enter a ring of the diameter given in column B, the hub should be chased down to the diameter given in column D and fitted with a specially made lock nut to the diameter given in column C.

If the hub serrations are worn smaller than the diameter in column E, the hub should be replaced. If the wheel serrations are worn to a larger diameter than the diameter in column F, the wheel centre should be replaced. All dimensions are in inches.