Here are some basic points you need to know for making correct tire recommendations.
Wheel Width: Distance between inside of flanges rounded to nearest 1/2". Ensure that wheel width is proper for tire size you intend to mount on it. All tire sizes have minimum and maximum wheel width limits.
Wheel Diameter: Distance from bead seat to bead seat across diameter of wheel. Must be exactly the same as tire rim diameter. Always check diameter stamped on the wheel and match the tire exactly.
Wheel Offset: Distance between wheel mounting surface where bolted to hub of drum and centerline of rim. Determines vehicles "track" or distance between tires on each axle. Keep the wheel offsets as close to original as possible to avoid steering difficulties or wheel bearing fatigue.