Random shaking

[Allinkdup8]

So i just recently put a 3 inch lift in my truck and put 35s on it, i got the tires balanced with the sandbags and put the hub spacers in for my offset wheels but i still get a random shake over 55mph and it randomly goes away and then comes back, im a pretty decent mechanic but this is stumping me, any ideas?

 

[JB1]

Truck info?
Lift info?
Spacer info?
Tire brand new it used

your gonna need to be much more specific

 

[Allinkdup8]

2015 ram 1500 5.7l, supreme suspensions 3 inch spacer lift, and the tires are AMP AT on gear wheels, -44mm offset

 

[Gary2]

Might want to try doing some searches on here and google for vibrations 1500 Ram . Many of us have come up with this vibe above 60 it seems. Mine don't do it till I try to hold a certain speed then after a few seconds it suddenly starts . Can be seen in the cup holder , feel in seat , not hardly anything in steering wheel . Kind of a pulsating thing that will drive ya nuts . Ram has bought back some trucks as they gave up, ran out of things to try . I will fix mine as soon as I find a Power Wagon I like . welcome to the club .

 

[Allinkdup8]

I didnt have the problem until i put the tires and wheels on, i drove the truck for a few months on stock everything and it was like a dream, i do the lift and wheels and it starts