This example shows a tyre width of 3.5 mm for Gauge 0 Fine.
For Scale7 remove more metal from the back of the wheel to give a tyre thickness of 3.2 mm instead of 3.5 mm.
3′ 2″ diam., 10 oval spokes, rectangular inner rim, 4¼″ apparent tread.
Hub 10″ face dia., ¾″ out from the tyre.
Source: GWR works drg. of bogie wheel for classes 2800, 2900, 4000, 4200, 4300, 4400, 4500, 4700, 4073, 5100 and 7200.
Casting: 22.2 mm tread dia., 17.0 mm i/d., hub 0.4 mm out from the tyre.
Casting prices and stock . GWR loco sets, price list
Scan of the castings in sets for a GWR 2-8-0 47xx, 4-6-0 Castle, 4-4-2 North Star.
4 Feb 2015