TOURING CAR SUSPENSION DYNAMICS: by Ben
Wilson . (Toe-in by: Mitch Lewis)
Can I say at the beginning, this is by no means complete or even completely accurate this is supposed to be a 'cause and effect' type list and not a complete course is advanced suspension dynamics. My aim is to give the beginner or even a more experienced racer a general overview of what all the adjustments on their car do.Important note - The more load you put on a tire, the LESS grip it will have. An initial note about tire behaviour. A tire doesn't just sit on the road, it rolls along. If you apply a side force to a rolling tire it will start to move sideways. The why of this is easier to visualise with a treaded tire. Imagine a brand new tyre with small, deep tread blocks (pro-line's road hawgs are a good example). Now imagine this tire rolling down the road, when the car starts to turn, the tread blocks touching the road will lean over. As the tire rotates, following blocks will land slightly further to the side than the previous block. This means that a tire can be moving in a direction different from which it is pointing without sliding. This effect is sometimes known as 'tread walk'. The angle between where the tire is pointing and where it is actually going is known as the 'slip angle'. As you add more weight to the tire, the tread blocks start to 'fall over' rather than just lean, this tends to overload the edge of the block and results in greater slip angles. As the tread blocks snap back into place, they make a squealing noise. Slick tires work the same way, but on a much smaller scale, imperfections in the surface of the tire 'grip' imperfections in the road surface much like gear teeth meshing. (Now you see why a wider tire gives more grip). |