front tires wobble

I have a 2000 jeep wrangler 4 cylinder manual 5 speed with 33x 12.50x15 A/T tires.

sometimes at various speeds the front tires will start to wobble. If i slow down it will stop. Then i can speed up.

The tires are wearing evenly. More in the middle on both tires.

I was going to replace the axle u joints first. then, front end alinment, then new tires.

What do you think.

Thanks

Patrick