I made a steel strut out of angle iron, and used the crank up and down winch from underneath a '70s Toyota pickup. Although seemingly made for small tires, it uses a sturdy chain and with the other piece of angle iron and a bolt, holds my spare tire up underneath the bus. I drilled a hole in the bumper to insert the crank handle I made out of 1/2" pipe, which cranks the tire up and down easily. It's been holding that 20" tire up there for 29 years so far.
