my bd on 37 to. spin s them just fine. these tires are skinny and weight 59 pounds most 37 are heavy that makes a big diffience. i have 7 to 10 percent grades all around were i live have no problame pulling the hill i roll around town in 5 gear all the time.
ran 35 for all most 2 year . both of my bronco have 4.46 and the same 37s i do have a muffler delete on it. and i live in hill country. that being said the terramax only weights 59 pounds and is a d rate tire. so my auto and my 7 speed have no problame tuning this tires. they may say 12.5 wide...
When you buy the cheapest Bronco Base 7 speed no boxes marked, add a 2" inch RC lift, 1.5" wheel spacer and 37 12.50 17 tire on steelies.
Tires are TerraMax RT
base with a 2 in rc lift 1.5 wheel spacer tires are terramax rt 37 12.50 17 d rate 59 pounds . the blue one is a bd with 2.5 lift same tires. they are skinny for a 12.50. the green is a base 7 speed.