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′ 1″ diam., boxpok welded from plate, 3½″ apparent tread. Hub 12¼″ face dia, level with the tyre.
Source: Winston Churchill measured direct at York in August 1995.
Casting: 21.6 mm tread diam., 17.7 i/d., hub level with the tyre.
Casting prices and stock . SR loco sets, price list
Scans of a casting in a set for SR 4-6-2 Bullied Pacifics
27 Mar 2013