rack noise

[cyberpapa]

Installed a new rack on a mini-van and turned it into a Hummer. At about 40 mph there was a low pitched (LOUD) humming sound that got louder as speed increased. I was using the square Thule bars. Moving the bars was not an option so I started to investigate a fairing. I found a simple fix that sounded too good to be true.
The suggestion was made to wrap a bungee cord or similar around the load bar. I saw different recommendations for how closely the spirals formed by the cord needs to be.
I used parachute cord and wrapped spirals that were maybe an inch and a half apart. Took the van for a ride and at least 80% of the noise was eliminated.
This might be common knowledge, but it was sure new to me so I thought I would pass it on. It works on the same principal as the spiral ridges you sometimes see on car antennae. Happy Hauling, Cal

[Lupe]

hmmm - interesting. I've not heard of this and I also have an annoying hum from my rack system now. How much of the bar did you cover with this cord? Does it need to be all the way across?

I think I'll experiment with this myself! Thanks

[Shep]

The humming is caused by a wind pattern that oscillates at a specific frequency. Doing things like adding a fairing, putting a pool noodle on it, or the above-mentioned wrapping p-cord do one of two things. A good fairing makes it more streamlined, so the air doesn't oscillate. The p-cord probabbly adds significant turbulence, so the air motion becomes more chaotic, and doesn't oscillate at that one frequency. Either way, just a small change can make a big improvement. :)

Shep

[cyberpapa]

Lupe.. I did go all the way across the front bar with the spirals of parachute cord. I only did the front load bar and am just experimenting myself at this point. Hope you have good results. Cal

[Tim Eubanks]

I don't know nothing about no ocillatin or frequency. Sounds like engineerin talk to me. MIne sing like a tone-deaf alto. Mebee I'll try some of that cord wrapping stuff. What's a pool noodle? I know what a pool q is and a egg noodle. Pool noodle? :myday"

[The Red Prophet]

Pool Noodle is the long hollow styrofoam tubes that kids play with in a swimming pool.

[Deuce]

Pool Noodle is the long hollow styrofoam tubes that kids play with in a swimming pool.

WRONG WRONG WRONG. A pool noodle is one a them thangs you cut in sections then split the sections to shove onto your gunwales so you can throw the boat on top of your truck without usin' one a them faincy racks.

[AR-Nimrod]

Pool Noodle

And there I was thinking it was one of those things that you cut up, split and stuck over your rack bars to provide padding for your boats...

[Deuce]

Pool Noodle

And there I was thinking it was one of those things that you cut up, split and stuck over your rack bars to provide padding for your boats...

That too. I actually finally found some cross bars for my OEM Expedition rack this year.

[okieboater]

I use it to pad the bottom cross bars on my cot (not my roll a cot, another cot I have) so it would not hurt my tent floor.

[Shep]

Of course, You can't use foam pipe insulation. That stuff just won't work.

[krash]

It was suggested to me to use bungee on mine, so I went to the hardware store and bought 12ft of 3/8 inch bungee, split it into two pieces and wrapped it around my bars after securing the ends into loops that go around the ends of my bars. Works like a charm and since they are stretchy, they have stayed pretty tight.

[AR-Nimrod]

Of course, You can't use foam pipe insulation. That stuff just won't work.

Exactly right! It's not colorful enough.