Not sure what size tires you have, and when you mention bigger, are you wanting a bigger tire on the same wheel, or are you thinking of increasing wheel size also?
There might be some blocks you put between the axle and springs, if you have leaf springs, and the axles are below the springs. This would also require longer U Bolts. If the axles are above the springs, you could "flip" the axles, not turn them over, but have them moved to under the springs. (do a search on here for flip axles, been covered several times). Regardless of method, suspension mods, tires/wheels, it ain't cheap.
2012 Ford F250 ext. Cab 4x4
2002 Jeep Wrangler Sahara
2008 Yamaha V-Star 650 Classic
2008 Work and Play 18LT