Prevent xtracycle hooptie rattling noise My Xtracycle hooptie rattles around when I go over bumpy roads when I don't have a passenger.   Does anyone have a suggestion on how to keep it from rattling?

I did move it to the most narrow position which helped but it still rattles around a bit.



Generic image of a Hooptie from xtracycle website
You have several options, and not one is going to be the correct one, so wiki it is.


Use old inner tube inside the mounting clamps.  Looks like there is some standard U-shape pipe clamps on the underside?  
Grease the side rails where they slide into the main body.  I would do this anyways because getting those ball bearing latches apart later is a pain.  It may reduce the metal to metal contact.
Black electrical tape on the side rails.  Related to #2, if you stretch the black tape enough, it may get thin enough to wrap around the ends and insert them into the main body.
Bar tape.  Somebody else suggested this, but wrap the whole top with bar tape.  You won't be able to take the sides off after (unless you do something else), but at least your kids won't complain about the cold, wet metal.