Gauge 3 Society standards:
Wheel back to back: 58.0 mm.
Recommended minimum wheel width at the tyre of 6.8 mm (minimum). These castings are also suitable for the earlier (pre May 2010) standard width of 8.0 mm.
Standard width over wheel bosses suits wagon wheels, but does not apply to Locomotive wheels with thicker scale hubs.
30 July 2016