Parker sweeper question

[dodge trucker]

I have one here, "Parkerette 7930" and it's in real nice shape except it's missing a tire. The rum is there, had to jump thru some hoops to get the right tire, (had to order twice nobody seemed to know what was different between the ones available, I knew that the 1st one was wrong as soon as I opened the package)
So I'm out shipping both ways, and the right one was alot more costly than the 1st one besides)
But now that I have the right one I'm having trouble getting it mounted

 

[dodge trucker]

Got it on, it was just more of a struggle than spooning on a 410/4 tubed tire.
This sweeper is in surprisingly good shape, looks like it was hardly even used. I just wonder how it lost the tire. Was a curb find, there was a real estate sale sign in the front yard of where I found it. Though, if I'd paid anything for the sweeper it would probably not have been worth it for what that rubber cost. Definitely built better than anything in the box stores currently.