Here's what I know:
basically if you want to run a tracto tire on a normal size rim you have two options, theres a small sized like 33 i think tractor tire that will fit on a 15" rim
then there's mine 18.4-16.1 is the measurement, they fit on 16" rims are about 46" tall and 18" wide
My particular tires are mixed brand but American Farmer is the one who makes them now
the ones in my size are actually not stiff like other tractor tires, I would compare them to a gumbo or ground hawg in stiffness, if you air them down on bead locks they will flex like a normal tire
in mud, loose dirt, trails, etc they do outstanding
rocks as long as its dry they do really well, I got all the way up on top of the big pipe that all the buggies had a hard time with at the uwharrie stables rock pile with my jeep no issues at 30 psi
when wet your gonna have issues on rocks big time unless you air down very low with beadlocks
if you do alot of rocks I would suggest running the front tires backwards and they tend to grab the rocks better since the tread kinda funnels the rock to the middle of the tire rather than out the sides when ran forward
on the road actually not bad at all they ride really smooth which was a surprise to me
I believe the limit on my tires to legally road drive is like 17 mph, I've had em to about 30mph
good luck trying to drive with them on the road though, I spent alot of time researching this myself and technically yes it is legal, but an officer will more than likely pull you over and ticket you for driving and unsafe vehicle on the road or similar then you have court costs and lawyer costs to pay and all of your time just to prove you were legally right in the first place.