I posted this on the Equipment page and got some good info but not exact answer. Anyone have a direct answer?

Larry, I bought these at auction a few years back. They are 15X26, (18.4X26), think they are off an IH of some sort. Had them on three different WD's/45's, they fit fine though kind of wide and no provision for adding weight. They're old but in great shape and actually taller than my 16.9X28's.

If I were to build a dedicated tractor ride machine I'd probably use these.

Larry-  The problem why no direct answer, is probably because they all ran into the same problem I did... they found a deal on a pair that 'looked close', but weren't on the machine anymore, so they don't know which machine they came offa'... ;-)

I think the bolt pattern on our D17's showed up on smaller combines of the late '60's through mid '70's, but once machines grew in size, they went to different patterns and tire sizes.

The combine wheels/tires on my D17 are (I'm fairly certain) 16.9-26's, came with more holes, on a larger circle.  Now they fit simply because I cut a pair of 3/8" steel plates about 12" diameter, added a center hole to fit over the hub centers, then marked and drilled them to accept bolts, then cut out the old center, and and welded them on.

For the 'Schwartz' WD project, I found a pair of irrigation boom wheel/tire assemblies, don't know the brand of boom they came off of, but they were a direct bolt-on, and those wheels are HEAVY... galvanized steel, a half-inch thick.

I recently acquired another pair, also 26" rim, but wider, and substantially taller.  I was GOING to use them on my WD, but I think they're gonna be too much tire, so I'll hafta find some other use for 'em.