That's an aweful lot of weight to be hanging off your tailgate. I had a 33 hanging off mine for a while and it started to rip the gate in two. I would look into a swing out carrier that can handle the weight of a tire and gas cans.
build thread: http://www.jeepforum.com/forum/f22/skyj-eccentric-build-1467426/ '90 YJ 5.2 magnum MPI, AX15, NP231 SYE, Dana 30 4.56 open/ 8.8 4.56 detriot locker. 1" shackles
2" BL, 4" stretch all on saggy waggy springs.