Depending on what you are using this information for, also consider things like the front and rear departure angles (you don’t want to scrape the front or rear when you abruptly change uphill angle), front and rear overhang (ditto), and distance from the wheels to the low central point of the car (you don’t want to high-center, or get stuck or dented going over the top of a hill). The spring rates are also pretty important as dagosa mentioned (look at the number of scrape marks on many ramp entrances), but this is hard to objectively measure and may only be done with a test drive. Wheel type can also be important if you need to take bumps at speed – many low profile “alloy” wheels are expensive and easily damaged even on roads with moderate potholes. Also, from experience, if you are worried about clearance, know approximately where the vulnerable parts of the underbody are in relation to your vehicle’s position (good way to practice this is driving over some soft containers of various heights in an empty lot and listen for the noise). Finally, if you have to go over things like rocks, curbs, etc. consider centering your tires on the obstacle and driving over it, rather than risking damage to the sides of the tires or to the underbody – tires are designed to go over obstacles; mufflers and oil pans are not. Good luck and hope this helped.