851 5.5" rear wheel. It even has the desired 'Nelly' on it. It's cosmetically a bit rough and the tyre is scrap being ancient and visibly split. It came with an 851 Aluminium swingarm that I needed at the time and is another part I've had to admit I'll never use. £25 collected in person from Clanfield, Hants.
That, Sir, is a bargain. Maybe 1/6- 1/8 th of what it’s really worth if the market was healthy. I’m not in the market sadly, as, like you I have a garage and store-room full of parts but particularly wheels, forks, shocks, exhausts, bodywork etc. from any number of Ducati 90’s and early 00’s desmodue and desmoquattro models and thinking about how to move some stuff on rather than buy more. I think this will have a 17mm spindle so a direct replacement for a 900ss and a 1” wider but straight fit replacement for a 600 or 750 carby ss or monster (but potential buyers do your own checks! )