We had 6.00x16's on everything but the '39 H, it had 5.50x16's. The SM-TA got 6.50x16's one day and they really didn't seem any wider or taller than the 6.00's. Never had 7.50x16's on anything. They really should be on a 6 inch wide rim.
I'd like to modify some 6x15 rims to bolt to the stock cast wheels on my Super H with the loader. I have 6.00x16's on it now, a 6 ply and an 8 ply matched brand, think BFG.
Had 11Lx15's on the frt of the 4010 WFE. The tierods were totally wore out on a tractor with 2500 hours? Running it the 20 miles home from the auction I wore the last of the 3 ribs off and wore thru the first 2 plys of the casing on one. Dad was taking it another 20 miles on the road and made it 5 miles and blew a front tire. Spent the rest of the day getting frt tires replaced. Put 11Lx15 implement tires on it. Steered fine except on sharp turns when you needed brakes anyway. Ran them for 3+ years with no appreciable wear.
I priced rear tires a couple times the last year for my M. Has 13.6x38. 14.9x38 are stupidly expensive. I'd like to put 15.5x38's on it, local Firestone dealer has a great price on 15.5 SAT2's. But reworking my 11 or 12 inch rims into 14's or new DW14x38's are roughly $350 each. $300 each plus 100 mile ride to pickup and 100 miles home. Think I'm going with a 13.6x38 Mitas. Really wanted Firestone, but has to be made in USA.