The SF trailer tires and the ones on the green Alvis are pretty darn close side by side to the Sno Trac with RW hay trailer tires. The tires fit very tightly right up to that ridge in the center of the track roller. From the underside it looks like the space after the roller ridge is a standard set-off spacer for the tire.
Just to let you know the wheels and hubs on my now sold pre pro Alvis were as in Numi's picture, one piece. and obviously taken from the hay trailer wheels bin. Cheers Numi.
I now see the difference in your larger center hub Nick, as is nicely pictured by mboxmike in the above picture showing both for comparison. I really must turn the lights up in the Cave when I am drooling over these well done retreads....LOL So much for a 'rare new unknown wheel variation'! After 4 years of looking at these oddballs, the obvious is pointed out. Pretty clever these Dad's with Trailer wheels that fit so perfectly on these rollers. Off to bed a bit earlier tonight after finding one of my three is as pictured by mboxmike. I am sure the other two will be the same when I find them tomorrow. Another lesson from 'The Kids on the Forum'.......LOL kwakers
to my own surprise, in between my spares I found a different version of the preproduction model shown on ebay!
I must have overlooked it in all the years - now I'm happy, as it seems to be worth about $300.........