By cap I mean an Undercover, on the F150. Thought of locking the brakes, blocking the wheels with wood-covered-rubber spray material. The cap is as slippery as a Rover seat. Using ratchet straps to keep trike in position as well. Our kayak trailer will be filled so that is not an option. Maybe even remove the seat. Maybe 67 mph at most. Have a month before we go north.