Symmetrical lift 3in concrete?

[cthulu]

Anyone running a two post symmetrical lift on 3in of concrete? most recommend 4in but I'm just going to be using it for sub 5k lb vehicles.

I've seen some fly cutting the cement and plopping down a foot of cement but I'd like to keep costs down if possible.

 

[duc916]

I have a 9k lift on a ~4" floor and it cracked the floor (ford f150). It is not the load straight down that is the issue, it is the torque applied from the offset load.

 

[Northeast Rod Run]

I wouldn't try to cut corners on cost with something like that. Do you even know what PSI the concrete is rated at? There is no way in hell that I would want to put a lift on 3" of a weak concrete

Better to be safe than sorry in a situation like that.

 

[mikeyr]

I'm just going to be using it for sub 5k lb vehicles.

that sub 5k lb vehicle sure will hurt when it falls on top of you, even its less the 5k lbs.