Tow Vehicle Roof Hum

[Bob La Londe]

Ok, I have a problem and I don't know how to fix it. I need a ladder rack on my Silverado 2500, but everytime I put one on the buffeting of the wind over the front cross bar causes the roof to vibrate and hum horribley. I have tried two different racks on the truck, and both do it. One has a square bar, and as you would think its worse. The one with a round bar is pretty bad to. At speeds over about 35 or 40 miles per hour the hum gets so loud that its pretty unpleasant. You can put your hand up aganst the ceiling of the truck and feel the roof vibrating very strongly. <br /> <br />Of course to keep this on topic for the forums, the time when it bothers me the most is when I use the truck to tow my boat up to Fisher's to fish a tournament. <br /> <br />Basically the roof of that truck is very flexible and any air tubulence is going to cause it to become a large sound diaphram. My Colorado has ridges molded into the roof to make it more rigid, but the Silverado is basically a plain flat surface. I have considered adding a wind deflector like a lot of people pulling fifth wheels use, but man thats a big ugly device. I have also considered making the roof more rigid by glueing some heavy rubber strips to the roof. I was thinking the rubber used on the keel of boats to protect the fiberglass on boats that are routinely beached might do the trick. Probably about 6 or 7 such strips run from front to back. (that would be a pretty pricey solution, and I don't even know for sure it would work,) <br /> <br />Any other suggestions?

 

[sangerwaker]

Re: Tow Vehicle Roof Hum

I think that pulling the headliner down and putting some noise dampener material against the metal would work excellent. Use car stereo type stuff, like Dynamat, or a similar type product. It is self adhesive and should do the job. Another idea might be to use a small bike rack wind deflector, like the Yakima ones I have seen. They mount on the front cross-member and are a smoked piece of plexi glass.

 

[KM2]

Re: Tow Vehicle Roof Hum

Just an idea: How about a deflector from Thule or Yakima the biking/skiing accessory companies. Those deflectors are small and designed to deflect the wind around a car/suv roof mounted bike rack. I'm sure you could get one that would fit your truck.

 

[sangerwaker]

Re: Tow Vehicle Roof Hum

Funny how us Minnesotans think alike, eh KM2?

 

[TilliamWe]

Re: Tow Vehicle Roof Hum

I am an Ohioan living in Illinois, but I am with the two Minnesotans on this. You don't need a huge wind deflector. That small one they are talking about might just deflect enough wind up & over that rack to stop the vibration.

 

[Mark42]

Re: Tow Vehicle Roof Hum

If you are still thinking of putting some strips on the roof, look at auto body side molding instead of the keel guards. A lot cheaper and will have a factory look. Also available in long lengths.<br /><br />Something like this:<br />

<br /><br />Or this:<br />

<br /><br />Might do the trick. Images courtesy of JC Whitney.<br /><br />Mark.

 

[JB]

Re: Tow Vehicle Roof Hum

Have you considered a F250?

 

[Bondo]

Re: Tow Vehicle Roof Hum

I'm from Neither Minnesota, Or Texas...........<br /><br />But, I like This Cure the Best..........<br />

Have you considered a F250?

 

[neumanns]

Re: Tow Vehicle Roof Hum

Hey not all minnesotans think alike, Pull the roofliner and add some lathe strips to give it some resistance from underneath or run some sheet metal screws into the crossmembers with some epoxy to seal them.<br /><br />Or go with the f-250, that may work also!!

 

[Kenneth Brown]

Re: Tow Vehicle Roof Hum

I really like my F250 but...... Its roof doesn't vibrate. It pops when you reach certain speeds. It pops down, then later it pops up. It also does it if you open the windows while at speed.

 

[Barlow]

Re: Tow Vehicle Roof Hum

hmmm.. never had that happen with my '02 F-250 quad cab KB .. you sure you in the right vehicle and not the wifey's mini van with the cow catcher attatchment? <br /><br />bob- few questions.. you have a bug gaurd on the thing?<br /><br />which racks have you used?

 

[KM2]

Re: Tow Vehicle Roof Hum

Sanger, not only do we think alike, we must have posted close to the same time because I had not read your's when I posted.

 

[Kenneth Brown]

Re: Tow Vehicle Roof Hum

Maybe its cause mine is a 89 and has a few more years on it.

 

[beniam]

Re: Tow Vehicle Roof Hum

You likely have two problems. <br />1 your roof resonates at the same frequency as your roofrack.<br />2 Your roof is drumming, meaning it is a large surface that pops up and down like the flat pice of tin that it is.<br /> You can make it heavyer(vibrates at a lower frequency, or you can make it stiffer.<br />Gluing something right in the middle of the longest span will help most. Anything that dampens the amplification of the vibration will help (rubber sheet, make shure it is dense). <br />Stiffeners, like a support, do best if attached with something like waterproof caulcing - lumberyard,bathroom caulcing-absorbs vibration. If you apply strips on the outside, caulk and screw. Predrill, tap with steel scew, back out srew and turn stainless steel srew in the hole.<br />Batavier