The Brick Experiment Channel (previously) increasingly adapted a remote-controlled LEGO car with a variety of different improvements in order to make the vehicle climb obstacles of greater heights with greater ease. The first test involved climbing the height of a book. The first change was made to the diameter of the wheels. More and more additions were made until the vehicle looked less like a car and more like a machine made specifically for climbing.
Testing a Lego car against different obstacles and improving it until it becomes a capable climber. Demonstrates what you need to consider: wheel diameter, gear ratio, 4-wheel drive, tire grip, breakover angle, weight distribution.