The Twelve was originally fitted with a 765x105 beaded edge tyre, from 1921 to 1926. From 1927 the standard became a 4.75 for 21inch crossply (475-21). The wheel and tyre changed again in 1929, when a 500-20 crossply was then fitted. Then in 1933 the standard changed again to either a 475-19 or 525-19 option.