I use similar to the brackets above. Except I just used the some white 10"x12" L-Brackets for shelving (even cheaper than the ones above) then put plumbing insulation on them and screwed them fast to the wall. didnt even use wood to mount them to the wall. Just drywall anchors.
'64 CJ-5, '74 Bronco, '79 CJ-7, '84 CJ-7, '92 XJ, '96 XJ, '99 XJ, '01 TJ, '01 XJ, 2013 JKU.
2013 Commando Green JKU
35x12.50/17 Falken Rocky Moutain ATS
2.5 RK X-Factor
17" Black Rock Vipers
Cut Stock Flares
Diablo Sport Trinity (garbage)
Sleeve, Truss, ARB, Chromo D30