On 23 Mar 2004 11:55:44 -0500, "Gordon Niessen" wrote:

Use the expanding foam. Fill one end with foam and then put the end
cap back on. The foam will expand to the other end. You may want to
have something to catch the excess so it doesn't get on you car.

Or you may want to have the racks off the car, perhaps standing vertical to
aid in the distribution of the foam. Perhaps it is possible to have a long
"straw" to get the foam to the centre and further along the bars. Would it
be worthwhile to have a string hanging down inside the bar in case you want
to remove the foam?

You could easily test the sound deadening properties on a small length
of pipe before filling your car rack. But I have seen it used to stop
noise on metal stairs and around drain pipes. Should work fine on the
inside of pipes.

And it will keep wasps from building nests inside - my use of foam around
the house. :-) Anyway, I guess the foam is light enough not to be a factor
if it doesn't work, but it also may restrict trying another method.

Now, do you suppose this will work with the rectangular Thule bars or is it
specific to round Yakima bars?

My understanding is that we are dealing with racks that have a fixed point
on the vehicle. If there isn't a fixed point, then rack noise can sometimes
be reduced/eliminated by simply moving the rack back or forward a couple of
inches on the vehicle.
--
cheers, Stephen