As kind of a "FWIW" follow-up to this thread:
I had purchased a set of the 8mm TTs from this outfit, in the event my Rapido 2-8-2 BR41 should need replacement tires.
I was running some of my HO scale German stuff the other day, and my marvelous Roco V200 threw a traction tire: as it turns out, those "N scale" 8mms were a perfect fit to this model. Now why a loco of this size and weight (24 oz.) would need traction tires in the first place is a puzzle, and probably best left for another discussion, I suppose, but in any case, I thought I'd pass this on...
Mark in Oregon