Toyo Balancing trouble

Hi all.  My name is Brandon and I'm new to the forum.  I'm having trouble getting my tires balanced.  I have an 05 F350 with an 8 inch rouch country and dual steering stabilizer.  I recently had 38x15.50x18 Toyo open country m/ts installed.  At 40 mph, the truck shakes and bucks.  The steering wheel shakes back and forth.  It is undrivable on the highway.  I was given two new tires, but it only helped a little.  Still bad.  Had all tires rebalanced, road force and dynamic.  Help.  Has anyone experienced this?  I've only read good things about these tires.  They cost me over $2400, but have had nothing but trouble.  Has anyone had a similar issue?  

I would check the steering joints to see if any are loose or worn. A problem that I see most do is put bigger wider tires on without replacing the worn out joints. Also, you didn't mention an alignment.....if you haven't done that then that could contribute to a lot of it. Good luck on finding the issue. When you do find out the problem post it here so guys can use the learning experience for future reference.  

YZ, thanks for the reply.  I did have a loose lower ball joint.  Changed upper as well while I was in there.  Noticed no change.  Tie rods tight, as well as drag link.  Most of my vibration is now coming from the rear, since the change to the new tires up front.  I don't think the shop wants to keep throwing tires at it, but changing the fronts did help.  I'm kinda lost.  I'll keep ya posted.

Thanks,
Brandon  

No your not alone,I have a 06 F250 with the 38/15.50/18 tires and at exactly 40 mph it bobbles up to around 45-48 mph then smoothes out. Have had tires balanced 4 times at schwab and took to another local shop and they got it closer, but it always shakes at 40 mph.
I will not purchace another set of them that is for sure. They are wearing well but at different speeds I get a shake and chalk it up to crappy tires. Used to run Fun Country tires when they were available in the same size and they were smooth as silk but can't buy those anymore.
I think it has something to do with the fact they are 106 lbs. and are not consistant weight all through. Frustrated myself, going to just wear em out and find a different tire for next set. Mark.....  
2006 F250 7" Icon Lift w/ Rancho 9000 4" turbo back no muff or cat toyo 38/15.50/18

Tried a different angle and let out all the air and replaced it with nitrogen.
Let me tell you there is a difference for sure. Played around with different pressures and there is no longer a shake at 40 mph. (ft29psi) (rr25psi)
Another plus with nitrogen is the lack of heat expansion. Understanding the molecule size is larger than regular air thus giving a firmer sidewall with the same pressures that air gives.

I no longer have the shake at 40 mph and the only thing I changed was using nitrogen gas. Nascar has it in every car and I can tell you there is a difference.
Give it some research and try it for yourself you won't be dissapointed.
Mark........  
2006 F250 7" Icon Lift w/ Rancho 9000 4" turbo back no muff or cat toyo 38/15.50/18