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.
Initially 3′ 2½″ diam. then 3′ 3″ with thicker tread, 8 rectangular spokes, apparent tread 4″.
Hub 12½″ face dia., 1″ out from the tyre.
Source: Sharpe Stewart works drawing.
Casting: 22.8 tread dia., 18.2 i/d., hub 0.6 mm out from the tyre.
Casting prices and stock . HR loco sets, price list
Scan of a casting in sets for a HR 4-4-0 Loch . HR 4-4-0 Skye Bogie
27 Mar 2013