1 the use of super single tires on a truck is to reduse weight unfortunitly they are more expenceive ad if you have a flat your shut down
2 tires ona lowboy will vary depending onthe lowboy the most common tire will be a 11x 22 standard tire
3 not sure on the axles and suspension on the AMT low boy sorry
4 again unsure of the tire sizes on the Groove and P&H cranes