Truck Vibrates And Shimmy's At 50 MPH

[GOPAPA]

My sons truck

This is a before and after picture of his truck.. He drove it after we put the all colored front clip on for 6 months or so and no problems .
Now it has problems with vibrating at 50 MPH ,,pretty bad.

The wheels on it now are what he drove on it before the wreck and after .

He had the front tires balanced ..he says the wheel berrings are pretty tight ,,hardly no movement by shoving in on top of wheel and pulling out on bottom ,,while jacked up..

It has sit out side through all weathers for close to a year ..

So,, why all of a sudden after driving with no problems ,,it now has this terrible vibrating a only 50 MPH ? papa