under slung frame

Are there any advantages of running an under slung frame? Is the geometry set up the same as over the axle frames?

yes geomotry is the same.

I was wondering the same thing? Wouldnt an underslung frame kill your lift?

Yeah, they won't lift near as much, but you also get to keep the back seat area pretty much stock in an suv.  You also don't have to do anything other than your wheel tubs in a pickup bed.

The downside is less ground clearance unless thats not a problem depends on the application and what ur trying to achieve.

i just did one on my build. its currently running 15"s with stock rubber, has about 8-ish inches of lift. bigger rims will equal bigger lift tho, not by a whole lot but when its doored, who needs crazy  lift.

my 2runner has an underslung frame as well as my v8 taco roadster and my buddies t-top taco the biggest challenge is getting the shocks mounted and rear brake lines ran i get 10" of lift w/ 20's i have 2" bumpstops on it so with those i only get around 8"  but i didnt build my truck to be low to ride high i prefer the street sweeper method 

The geometry is the same on a traditional frame, an underslung frame or an ornamental iron frame.

One of the big advantages I can see with an underslung chassis for us truckers would be in a towing application. Having the notch area tied together on the underside would help keep the notch area from flexing open or closed under the forces applied by whatever you are towing. Obviously the heavier the trailer the more effective it will be in the field. I would do a standard notch tied underneath for a tow rig (if I had one, lol) with a properly chosen sleeve bag to handle the weight. Thats my 2 cents on the subject anyways