Weird Hopping from Rear of Truck

[DieselFarmer6.0]

I posted this before but havn't seem to have found the problem. I just leveled my truck and put 35s on it. At exactly 45 mph I get a weird up and down shaking from the rear of the truck. The steering wheel doesn't shake it's only the rear of the truck. At 48 mph it will stop. Any suggestions on how to fix this or know what it is? Thanks

[Special]

I don't know, but you could try to rotate your tires and see if it makes a difference. It sounds like something is out of balance. You also could try to change the air pressure. There is more weight on the front tires than the rear. I would first try to let 5-10 psi out of the rear tires.

[Special]

If you just put larger tires on it, you may just have to get use to them. Different size and width tires have different handling characteristics. It may be normal.

[DieselFarmer6.0]

yea, I was thinking about putting my old wheels back on to eliminate that option. Could it be that my driveshaft isn't aligned?

[Special]

I doubt it. Double check your air pressure. The last time I had tires put on they put 95 psi in them and my truck danced all over the road.

[DieselFarmer6.0]

I just put air in them when I put them on and they are rated for 65 psi. I filled all of them to 60

[DieselFarmer6.0]

bump..............

[DieselFarmer6.0]

Ok so I think I found out what the problem is. I had my wheels re balanced and then I put them back on the truck. I was getting the same problem as before so I took the centercaps off and ran the truck to 45 mph with it jacked up. I was looking at the center hole of the rim and its not lining up with the center of the hub. There is always a space but when you look at it rotating you can see that the center of the rim moves in and out of the center of the hub. Am I mounting my tires wrong? has anyone else had this problem and know of a way to fix it. I am pretty sure that this is the problem and would like to get it fixed asap. Please help