It looks very much like a Harwil wheel, if you scratch some paint off, you may find text Harwil. However it may also be British Hub or a Webb, they all make wheels of that kind. Harwil were used in an Excelsior and Ok Supreme and many others.
I am looking for all kind of pre war 4-stroke Excelsior stuff, also contact for someone who owns several Excelsior bikes. Im especially interested about frame from mid -20s. Also Blackburne OHV engine. Thanks.