I have an '09 F-150 FX4, and just recently, put on some new XD wheels and a ProComp 6" lift kit with 35x12.50 Pro-Comp XTreme AT tires. This is where the fun began (or not):

Phase I: When I picked up the truck, it looked great and seemed to ride fine until about 50mph. Starting about 50, the truck started to vibrate and jump around like crazy. The following day, the shop rebalanced and re-aligned the wheels, but the problems continued.

Phase II: The shop took the truck back in and removed the Pro-Comp coils and shocks and replaced them with the lower end kit (stock coils with a spacer) and replaced the tires. The ride is much softer (more like stock...which I don't mind), but again, the truck vibrates and shakes like crazy over 50mph. The steering wheel shakes from side to side about a 1/4" while driving. It does stop around 70, but then the back end seems to hop around a little bit.

I have heard from some other people that these Pro-Comp tires are terrible about doing this type of thing, and even though I have now had 2 separate sets of tires, I am wondering if my tires might be the issue.

Can anyone help me out here? I love my truck, but this entire ordeal is NOT making me very happy. I have heard that the Toyo MTs are the tire to go with. Anybody else experienced this issue?

Mark

 

It sounds like the tires are out of round. A good shop could shave off the high spots (true them).

 

I have a 2009 FX4 6" Pro-Comp & 20'x 35" Pro-Comp A/T tires. My rides fine, no shake. Who did the work on your truck, sounds like it maybe the alignment.
I dont under stand why they would take off the coils & shock?? Its all new.

 

Just by the steering wheel acting like that, I would say from m experience that it is 95 % a tire issue.

 

4 Wheel Parts did all of the work. They have redone the alignment 3 times and the balance 4 times so far, and it never makes a difference. They replaced the coils and shocks thinking that they were just too stiff for the ride I wanted. The Pro-Comp coils and shocks were incredibly rough. You could feel every nook and cranny of the road.. both good and bad.

 

Thats what I am thinking at this point. They have already put a 2nd set of tires on (both the same brand), and both sets did it. This set is better than the first, but not quite enough. I think I am going to have them throw some Toyo MTs on it and see how it does then.

At this point, I feel like I am pretty much out of options. Might as well try 1 thing at a time until its fixed!

 

I will tell you this. I had put Ltx at2's on my 06, truck pulled HARD the right, as in take your hand off the wheel and you would cross 4 lanes of traffic in 5 secs flat. Shop put three different sets on and it still did, I told them F' it and put the crap generals back on and get me my money back, which they did.


Guess what? truck tracks and drives as straight as can be!

I guess you could say are trucks are picky!

 

are you sure they put everything on correctly and everything is tight? if you have tried another set of tires and had the same result, i would start to lean in the direction of they might of done something wrong.

just something to consider.

 

Makes sense, When I first got my Nitto's all 4 were out of round. Almost like they were oval, couldn't hardly keep it on the road. Called Discount Tire Direct (where I got them) and told them the problem. I shipped the tires back and got a new set. Rode much better, but still have a little hop in them every once in awhile.........I think its temp. related.

So if you sent back the first set, and the 2nd set is the same, sounds like a issue with the lift.

 

If it's a vibration problem, it is tire or wheel related. When I have run across this in the past, we have put each tire mounted on the balancing machine and visually checked for out of round. This also lets you check the wheel. I will say that it is odd to have two sets oor (out of round), it could also be their balancing machine out of calibration-they must be checked periodically. You might try another shop and let them balance your tires.

 

I would also agree on taking it to another shop - at least to check the alignment and tires. Hopefully you are not being charged for all this rework. Good luck with this and let us know what the issue finally was.

 

I think you hit the nail on the head. I've never heard anything good about any 4 wheel parts works.

To your issue I believe that the tires are at fault. a out of round tire will balance out fine but still cause issues.

 

Well, I would agree, but I must admit... the guys in the shop have been great. They haven't given me any trouble and they have gone out of their way to accommodate me. At the same time, I just want it done.

I think that I am going to control the next steps and take things 1 step at a time until its resolved. Next step... 4 new Toyo MTs.

I'll keep everyone updated on the progress.

Mark

 

Just waiting on some Mickey Thompson ATZs to come in. I should have them mounted up and Saturday and have an update for everyone.

 

mickey thompsons are great tires i have had 2 sets of them, one on each of my last two trucks then the last time i had to put tires on my 2004 xlt with a 6 inch pro comp lift i was short on money so i went with the pro comp extream AT and i to ended up with a vibration, must be sumthn with the tires my mickeys where MTZ and road smoother, you should love them mickey thompson i now i did