You will not need an extension for nearly every type of pickup and most SUVs.The distance from the hitch pin to the leading edge of the canopy shaft is 24.” Please measure accordingly to determine if your vehicle requires an extension.SUVs with larger hatchbacks, such as a Suburban or 4-Runner will require a 7” extension for full articulation of the rear cargo door.Horizontal swing gates, such as a Jeep Wrangler, require a 12” extension and larger vehicles with horizontal swing gates, such as the new Ford Bronco, require an 18” extension for full clearance.