Buick 2004 Rendezvous Owner's Manual page 132

Notice: Loading cargo on the luggage carrier that
weighs more than 220 lbs (100 kg) or hangs over the
rear or sides of the vehicle may damage your vehicle.
Load cargo so that it rests on the slats as far forward
as possible and against the side rails, making sure to
fasten it securely.
When you carry cargo on the luggage carrier of a
proper size and weight, put it on the slats and distribute
the weight evenly. Then slide the crossrail up against
the rear of the load to keep it from moving. You can then
tie it down. Cargo containers must be loaded on the
crossrails only.
2-42
Don't exceed the maximum vehicle capacity when
loading your vehicle. For more information on vehicle
capacity and loading, see Loading Your Vehicle on
page 0-0.
To prevent damage or loss of cargo as you're driving,
check now and then to make sure the luggage
carrier and cargo are still securely fastened.
Loading things onto the luggage carrier can interfere with
the performance of your XM™ Satellite Radio System.
Your luggage carrier has release levers within the end
of each crossrail support.