What is the maximum load for 1 pair of...
What is the maximum load for 1 pair of Thule Artifical Rain Gutters
What comes into play is te rest of the rack and what you're putting on it.
Generally--I say again...generally--most Thule and Yakima racks when set up properly hold up to 165 lbs. However, adding that much weight to the roof of your vehicle radically changes the center of gravity and may cause extremely adverse reactions when braking and/or maneuvering at high speeds. You should always attempt to keep weight up top to a minimum. And make sure your canopy can actually support what you plan on carrying up there. And the 165 lb. number I threw out their refers to all four towers--not just one pair. Always check your vehicle and canopy owner's manual in regards to weight limits, and observe all installation weight limit guidelines when purchasing car rack components.