Front driver side droning.

A tire balancing weight might have fallen off rendering the tire unbalanced and resulting in the vibration at speed.

If that is not it, there could also be something wrong with the suspension up front like the shock absorber or strut.

Most likely a tire/wheel balance issue. The weights that are used to balance the tires can sometimes fall off. Generally how far out of balance it is determines when and how bad it will shake. Unfortunately this is not fixable without a tire balancing machine, has to got to a tire shop.

Were the tires rotated or replaced recently? Most major tire shops will check the balance for you at little or no charge if you take it back to the shop where the work was done.

You can also try to identify the problem tire by rotating the front and rear tires one side at a time. For example, if the vibration is coming from the front, swap the front and rear passenger side tires and drive the vehicle again. If the vibration moves to the back it's most likely the (now) passenger side rear tire that's out of balance. If the is no change, try the driver's side tires.

Hope this helps!

loose bolts somewhere in the front end? you have had lots of work done there. wheel weights can fall off or a rim can be difficult to balance?

A likely cause is the front tires are out of round or out of balance or both.

Tires are the most common cause of excessive vibration at highway speed assuming the hubs are good and the bearings are tight, and the front end parts are all tight and in good condition.

I just replaced 4 tires on my 1997 Cadillac Deville Limousine and it made a great difference in the ride and control, and got rid of a tire that had a 1/4" bump in it as seen by the tech that spin balanced it for me.

Try to have it balanced first, and check for out of roundness, and also inflate the tires to the max. pressure allowed by the specification as indicated by a placard on the inside of the driver's side door.

Good luck on getting rid of this vibration problem at 50 mph.

I'd take it back,& explain & have them re-check what they did, and ask if tires were balanced.

poss broken belts in tire(s) shocks

Check your tire balance and right front wheel bearing

it sounds like you may have a bad set of wheel bearings on one side or the other.which would mean you have a bad cv joint or one that is going bad. you may want to try to figure out which side the wobble is on and inspect that side.i suspect its going to be the side where you had the problem with the tire.

You should have the same size tires in the front and back. By having 2 different sizes, you are changing the gear ratios between the front diff. and rear diff. You could wipe out the t-case especially if it is full time 4wd.

I'm going to bet that you didn't do anything about checking the following:

1. Tie Rods and ball joints.
2. Shocks/struts...front and rear
3. Wheel balance
4. Condition of the tires.

If you don't know how to check the first two, do the following: jack front wheel up and insert a stand. Then take the bottom of the tire and pull up quickly and hard...does it 'click'? Now, do the same from front to back. Up and down wear is ball joints...side to side is tie rods. Get a mechanic to help you. Many chains will inspect for a modest fee.

If a tire is worn because of worn front end parts...the wheel can't hold a proper position in relation to the steering wheel...it wears the tires. They go out of balance and will shake at 25 mph. Check for rounded sidewalls and uneven wear. Replace the tires after getting new front end parts installed and aligned. Check your shocks/struts for excess wear or leaking. They contribute poor ride, to wear and sloppy handling