I have a factory rack for my Tahoe and just picked up the V shaped foam blocks to transport my SOT kayaks with. Holy Crap they rumble! Once I get up to 40 MPH the rumble starts and just gets louder as I gain speed.
Is this normal with the foam blocks or just kayaks on racks in general? Should I take back the foam blocks and get the bar wraps instead (has the store logo on it) Would the Malone J racks be quieter?
Thanks for the help!
Allen
a few questions
was with your boat on or off the tahoe?
Were you using straps to hold down the boat?
Did you have all the hatches sealed?
If it was with the boat on and using straps
you con start by putting a few twists in the strap before you cinch down. straps often get
a harmonic flutter at speed.A few twists in the strp breaks up the flutter.
Depending on the air flow and the opening on the kayak you might also get a whistleing ( think blowing into a empty bottle )
also
dumb question, but does your taho have a sun roof? was it open? They have a little retractable air deflecter that pops up when its open, if you have it open and the deflecter is held down you will get a booming sound/feeling the faster you drive. Its pretty annoying.
+1 on the straps
Personal experience.
I also use foam blocks on factory racks.
I went camping with a friend, and his wife. They borrowed a kayak, had it strapped to the top of the car. We pack up to leave, and being like I am, wnet over to say good bye, and check how they had the boat strapped down. Well, it was strapped down real tight, with the straps flat against the hull. I must have had a strange look on my face because they both looked at me and said “What?”. I told them that they might want to put a twist in the straps because they can make noise if they’re flat like they had them. The guy they borrowed the kayak from told them that the straps should be flat, and they didn’t want to do it again, they didn’t have any noise on the way to the camp, so they left it like they had it. There was no saftey issue, so be it. They hit the road about five minutes before me. I’m driving down the road, speed limit 50, and see a car on the side of the road, flashers on, and a boat on top that look familiar. Guess who it is. Of course I stop to help my friends. I did not get a friendly greeting though, my friends wife was curseing a blue streak directed at ME. Seems it was MY fault for mentioning the strap noise that made it happen. She was still cursing me out as I was laughing too hard to help them RE-strap the boat on the side of the road. This time with plenty of twists.
They are loud regardless
I have Thule load bars and they make an extremely loud roar when I drive. Once I get a boat strapped down I can’t hear it. A fairing would be an option but not for factory bars. I would suggest taking the foam blocks off when you aren’t transporting a boat. Most factory bars are wide but not very thick top to bottom. I would assume this is to cut down on wind noise.
Just pop in a good Neil Diamond record, er, go with “In My Lifetime”, and you will forget all about the noise…
I have Thule bars
with saddles, which probably have even more of a high profile on the truck roof than the foam blocks, but I use a fairing and have never heard a thing.
What SOTs are they?
I wonder if the contours of the kayaks are causing the noise.
Once in a great while we rooftop our sea kayaks (decked) on a Tahoe, using cradles. There is a little wind noise and painter-line noise, but nothing like what you described.
Can you turn the SOTs upside-down and still have clearance from the roof?
Wrap w/rope
Wrap the front bar with 1/4" rope. Spaced about 2" between the loops. Worked well on my Thule load bars.
Answers 
Thank you all for taking the time to respond!
No hatches on the kayak (O.K. Scrambler)
I did however take great care to ensure all straps were FLAT & tight ha ha.
In the morning I am transporting a Pelican Castaway and a Scupper Classic to the other side of the island. I will put a few twists in and report back at the end of the day.
Thanks again!
Allen
also
keep your sun roof closed, if it has one…
IT WORKED!
Twisting the straps was the key! A very nice quiet ride was had by all.