I've got a 2010 1500 Crew with a Truxedo cover on it. Ever since I got the truck, I've had this vibration eminating from the rear end at higher speeds. A few months ago, I noticed that the vibration was in exact match of what the cover seemed to be doing. I'm wondering if anyone else has this issue and, hopefully has some sort of fix. It isn't so bad that it is undrivable, it's just mainly very very annoying.

 

How is it fastend to the box...???
If it has some sort of aluminum framework, loosen the framework, and re-position it.

Are your tires slightly worn or out of balance, THAT alone will make the cover vibrate.
Also check your tire pressure, you`d be amazed at what improperly inflated tires can do.

Keep in mind, the stock shocks on these trucks just plain suck, you can end up with slight wheel hop and cause slight shakes and vibrations.

 

It uses 3 metal support bars between the cab and tailgate. Each spaced a couple feet apart. The cover is fastened to them with some nylon and sewing.

The tires are all the same pressure (40 psi) and, they are balanced as well. The wear is good on them also. I bought them a year ago and I keep up on the rotations.

From what I can see in the rear view, the wind pushes the cover causing it to flutter slightly. The movement is only probably 1/4" at most. This fluttering hits the support bars constantly and causes the vibration. It doesn't happen at all if I have the cover rolled up and stowed against the cab. I usually carry an emergency kit up against the tailgate though (a toolbox, auto fluids, jumper cables and a few other odds and ends.) So, it's almost always covering the bed.

 

Well, it sounds like a design flaw on the tonneau cover frame itself. Should have had more cross bar supports.
I would definately contact the manufacture and complain about it. Squeaky wheel gets the grease.
They might even give you an extra support bar for free to put in there to support it better.

An after thought you could try:
Go to a hardware store, get some 3/4 inch foam tape, attach it to the top of the supports, that should help tighten it so it dosent flutter.
Also, just a thought, did you install any type of seal around the back of the box where the tailgate close`s up to the box...????

 

Sounds like a standard cheap tonneau top. It'll tighten up over time as the top shrinks. If it is like the last one I had, the 3 bars have a slightly different arch to them and should be labeled front, middle,back. Make sure you have them in the right places.

 

The bars are all the same flat shape. I had one on my old truck, an '05 Colorado, and I didn't have that issue at all. The Colorado is much smaller then the ram though so the space between the bars is less. Making it less subject to the fluttering. I'll give the foam tape thing a shot. It would be nice to have an extra bar though. Respacing the bars so that there is a shorter dead space between them. There is also a tightening screw on there but, it doesn't make much of a difference on the fluttering. There is a seal where it meets the tailgate also. There is a rubber flap that meets up with the tailgate to form a seal. In the winter it actually causes the tailgate to freeze shut because of it.

I wouldn't exactly call it cheap either. It was 420$ and the company has extremely good customer service. This sounds more like a design flaw. All it needs is 1 more extra bar on longer bed, larger trucks.

 

Not sure if the foam tape trick will work or not for ya,
alot depends on how tight vs loose the cover is.
The real fix would be to add another bar.