Interesting!
Well, somebody here has the answer for you, I hope, because we've gone through all I know to check.
On my '65 GMC firetruck (a 4400), I had the RH-5s on a 6-bolt pattern. They were pretty challenging to replace, but we eventually found 7 single piece tubeless wheels on the 6 bolt pattern. Some came from a school bus and the others from a '70's U-Haul F600.
At least its Friday
