I have not seen a 37" tire that is rated for a 7.5" wide wheel. But there may be one or two out there. Most 37" tires are rated for an 8.5" to 11" wide wheel. Many tire shops will not mount a tire on a wheel that is narrower than the tire is rated for.
Another aspect would be backspacing, typically you need backspacing of 5.2" or less to run a 12.5" wide tire. And being a 37" tire only makes that requirement more important.
A third aspect would be everything else you would need to safely and properly run 37's. But that is a big can of worms.