rack noise
rack noise
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
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
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Re: rack noise
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
I think I'll experiment with this myself! Thanks
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but you'll never catch me complaining about too much of that southern rain.
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- Shep
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Re: rack noise
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
Shep
Paul Shepherd
"Believe me, my young friend, there is nothing - absolutely nothing - half so much worth doing as simply messing about in boats (said the water rat solemnly)." - Kenneth Grahame, The Wind in the Willows
"Believe me, my young friend, there is nothing - absolutely nothing - half so much worth doing as simply messing about in boats (said the water rat solemnly)." - Kenneth Grahame, The Wind in the Willows
Re: rack noise
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
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Re: rack noise
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
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Re: rack noise
Pool Noodle is the long hollow styrofoam tubes that kids play with in a swimming pool.
Wait... What?
Re: rack noise
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.The Red Prophet wrote:Pool Noodle is the long hollow styrofoam tubes that kids play with in a swimming pool.
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Robert Frost
Robert Frost
- AR-Nimrod
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Re: rack noise
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...
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...
Chris Crawford
Some people don't know, what they don't know.....
Some people don't know, what they don't know.....
Re: rack noise
That too. I actually finally found some cross bars for my OEM Expedition rack this year.AR-Nimrod wrote: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...
You come too.
Robert Frost
Robert Frost
- okieboater
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Re: rack noise
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.
Okieboater AKA Dave Reid
We are not sure when childhood ends and adulthood begins.
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We are not sure when childhood ends and adulthood begins.
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- Shep
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Re: rack noise
Of course, You can't use foam pipe insulation. That stuff just won't work.
Paul Shepherd
"Believe me, my young friend, there is nothing - absolutely nothing - half so much worth doing as simply messing about in boats (said the water rat solemnly)." - Kenneth Grahame, The Wind in the Willows
"Believe me, my young friend, there is nothing - absolutely nothing - half so much worth doing as simply messing about in boats (said the water rat solemnly)." - Kenneth Grahame, The Wind in the Willows
Re: rack noise
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
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Re: rack noise
Exactly right! It's not colorful enough.Shep wrote:Of course, You can't use foam pipe insulation. That stuff just won't work.
Chris Crawford
Some people don't know, what they don't know.....
Some people don't know, what they don't know.....
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