I have carried a hydraulic jack for years. Found a nice scissor jack and decided to switch over. I have never had a flat and don't know if the hydraulic would fit under the axle if the tire was flat. I have used the hydraulic for maintenance. Decided I don't really want to find out it doesn't fit when I really need it so I switched to a scissor jack I know will work. Wondering what others carry or not carry and why???