Q: “I’ve been told to have a light grip on the steering wheel, but I’ve also had it almost ripped out of my hands while going over a bump in the track. So how hard should I grip it?”
The lighter your grip, the more sensitive you’ll be to the feedback coming through the steering. Keep in mind that the steering wheel is not just an input device (something you use to make the car do something), but it’s also an output device (you get feedback about how the car is handling, as well as sensing how close the tires are to their limits through it).
Of course, as you’ve experienced, with too light a grip you can lose control of the steering wheel – and your car! So you may have to tighten your grip in certain areas of the track, and lighten it in others.
I will say that your steering wheel design and surface of the wheel play a big role in how lightly you can grip it. I highly recommend you take a look at what Ed Dellis does at PersonaGrip (http://www.steeringwheelguy.com). By custom-molding the wheel to your hands, you can use a lighter grip while feeling confident you’re not going to lose grip of it.