Not sure what brand tyres the OC used originally, but looking at the 1927 OC catalog show a coarse button tread. Also seen in other catalog illustrations, such as the 1924 OW/OB models.
Starting in 1926 in the EW catalog, and also still seen in the 1930 catalog is a Huchinson tyre, the tread of which was block, made up of an endless procession of capital 'H'.
-Doug