I have a factory reinforced back bumper on my FR Surveyor so I bought a bumper carrier. I did not like the "under the TT" arrangement and removed the spare. However, for short trips, I usually carry the spare in the back of the TV.
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Ram 2500 diesel / FR Surveyor 251rks
I bolted two 2.5" x 2.5" square metal tubes side to side on the frame toward the rear of my 5th wheel. Between them, I installed a spare tire winch/hoist I bought through the parts department of a GM dealership. I crank that spare up against those metal cross tubes same as I do the spare up under the rear of my truck.