3′ 0″ diam., 9 oval spokes, vee inner rim, 3½″ apparent tread, 6″ tyre width.
Hub 10¼″ face dia., spreading to 14¼″ at the base rim, 1½″ out from the tyre.

Sources: 4MT measured direct and BR Derby works drawing.

Casting: 30.0 mm tread dia., 24.0 mm i/d, hub 1.4 mm out from the tyre.

Casting prices and stock . BR loco sets, price list

Scan of castings in a set for a BR Britannia . BR 4-6-0 4MT with prototype photos