Johnny O' Connell

Driving Tips - Tip 1 | Tip 2 | Tip 3 | Tip 4 | Tip 5

Weight Transfer
Probably the most important concept for a driver to understand, as far as vehicle control is concerned, is called weight transfer. What it entails is the understanding of how weight moves around a cars tires as you drive. It's really a common sense thing when you think about it, but most people really don't put much thought into driving I'll go over it.

Lets say you have a 4000 pound car that is perfectly balanced. If you were to put bathroom scales underneath each tire, each scale would read 1000 lbs. Makes sense ? Good. Now, lets say that the car is doing 100 MPH...and you are in a wind tunnel so that aerodynamics are not a factor. You are not speeding up or slowing down...just holding 100 MPH. If at that moment you put scales under the tires, what would they read ??? That's right, 1000 pounds under each tire. Pretty simple to follow I hope.

Now it gets fun. Lets say that all of a sudden, your dog runs out in front of you. You don't want to hit your dog, so you go to the brakes. What happens ? The front of the car goes down, and the rear comes up. Now if at that moment you put bathroom scales underneath each tire, what would the scales read ? Obviously it would read higher numbers at the two front tires, lets say 1500 lbs each, and the rear would be lighter lets say 500 pounds each. Why this is important is that just by going to the brakes we have changed the handling characteristics of the car. Because there is more weight/force on the front tires, they are going to work better and be much more sensitive to steering input. Combine with this the fact that the rear tires have less force in them, and you can see how the rear will have less grip. As a result, when I move to steer around the dog, I need to be careful not to spin my car out. When on the brakes the car will be unsettled, and can easily spin if turning quick. Hope that makes sense. we are driving down a different road...holding our speed, and ahead we see a what do we do ? That's right, hit the gas !!! Again, when we do this, we change the handling characteristics of the car. When it accelerates the front of the car goes up and the rear of the car goes down. If again we put scales under the tires, they might read 500 pounds in the front and 1500 pounds underneath each rear tire. Is it a good day for the squirrel ??? Yes, and here is why. When I went to the gas, I added grip to the rear, but took grip away from the front, thus when I steer after the squirrel, my steering is going to be less responsive and the car will not steer as quickly. Makes sense ???

Understanding weight transfer is key to racers, but also everyday street driving. Sooner or later everyone has a moment while driving when they need to perform with skill. Knowing that being on the brakes will improve steering input, and that by being on the gas accelerating reduces steering quickness can for sure help you. As we go through the season, and cover more stuff (oversteer, understeer, accident avoidance, etc) almost everything comes back to understanding this one concept.

Finally, know that these tips are meant to make you a safer street driver, and not a racer. Driving on the streets is way more dangerous that being on a race track, and always a good way to get into trouble is by speeding. If you have the need to hang it out, find a race track to practice at. I know that Road Atlanta has days when you can take your street car out and work on your skills in a safe environment...;and guess that others do as well. If you don't have luck there, call the SCCA and get into some of their stuff such as auto-crossing. I know a lot of pro drivers that began that way. Later !