If you order spacers for the rear wheels of an RK37HC double check your bolt thread pattern. I just got 6" Bora spacers and they came with 16x1.5 bolts with sloped heads. (Those have to go inside the spacers and attach to the wheel hub.) My RK37HC has 16x2.0 bolts with flat heads so those won't fit the tapped holes in the spacers. Motorsports-tech is responsive and will send me replacement spacers. They said that in the past the RK37 tractors took the 16x1.5 bolts.
So if you are buying spacers check your bolt thread measurement - fine or coarse.
So if you are buying spacers check your bolt thread measurement - fine or coarse.