This example shows a tyre width of 3.5 mm for Gauge 0 Fine.
For other standards remove more or less metal from the back of the wheel to give your chosen tyre width.
850 mm (2′ 9.46″) diam., 9 oval spokes, rectangular inner rim. Apparent tread 71 mm.
Hub face dia. 270 mm, 10 mm above the tyre.
Source: Works drawing.
Casting: 18.9 mm tread dia., 15.8 mm i/d,
hub 6.0 mm dia, 0.2 mm out from the tyre.
Casting prices and stock . Netherlands, loco sets, price list
Scan of a casting in a set for a Netherlands NS 3000 class
8 Sept 2017