In the simplest form of steering, both the front wheels always point in the same direction. You turn the wheel, both point much the same way and around the corner you go. Except that by doing this, you find yourself with tyres scrubbing, loss in grip as well as a vehicle that ‘crabs’ nearby. So, exactly why is this? Well, it’s the same you need to consider when looking at transmissions. When a car goes around a corner, the outside wheels travel beyond the inside wheels. In the case of a transmission, it’s why you need a differential (start to see the Transmission Bible), but when it comes to steering, it’s why you want the front wheels to actually part of different directions. On the left is the diagram from the Transmission Bible. You will notice the inside wheels travel around a circle with a smaller radius (r2) than the outside wheels (r1).