Here is a good article I found on sway bars in grass roots motorsports. Yes they may have good information, but ford engineers have to tune their cars conservatively. Again, my car only shows oversteer during transitions, wich they indentify as being perfectly acceptable.
The Effect of Anti-Roll Bars Upon TLLTD
Ideally, you now understand how an anti-roll bar can be used to limit body roll, and you understand that reduced body roll can lead to a reduction in adverse camber changes for better tire traction. But what may not be obvious is the effect of anti-roll bar changes upon TLLTD (understeer and oversteer.)
In fact, given the above information, one might even assume that a firmer anti-roll bar, which leads to better camber control, would lead to better traction. If we add a firmer anti-roll bar to the front, traction loss diminishes, so understeer is reduced, right?
Wrong. Let's evaluate more closely the meaning of TLLTD-tire lateral load transfer distribution. Stated another way, we might describe TLLTD as the relative demand of side-to-side energy control that is placed upon the tires. Because a firmer anti-roll bar allows less deflection, it will transfer side-to-side energy (lateral loads) at a faster rate.
As the rate of lateral load transfer increases, additional demands are placed upon the tire. So if we install a firmer anti-roll bar in the front, then we increase the distribution of lateral load transfer toward the front tires. This increases the front TLLTD value, which will result in additional understeer, holding all else constant.
The same logic also holds true in the rear. A firmer anti-roll bar in the rear will increase the rate of lateral load transfer, placing more demand upon the rear tires, accelerating lateral traction loss and creating more oversteer, holding all else constant.
This is why blindly adding parts to your car may not produce the desired results. A wise consumer consults with-and buys from-knowledgeable experts that have the tools to make informed tuning recommendations.
I Want a 50 Percent TLLTD On My Car, Right?
Since on paper a 50-percent TLLTD indicates a balanced chassis, many enthusiasts are tempted to jump to the conclusion that this is therefore desirable. They may think that all cars should obviously come this way from the factory. Unfortunately, this is not the case-and the considerations are not that simple.
In reality, a car with a 50-percent TLLTD is literally on the constant brink of oversteer. And there are many factors that can quickly and easily take the car from the brink into a full-scale, out-of-control, spinning-in-circles disaster.
For starters, consider the effects of weather conditions that might create a wet or icy road surface. Or imagine that the driver happens to apply too much brake late into a turn-a common mistake among novice drivers. Or consider the effects of varying tire temperatures, tire pressures, or tire wear-all of which will have major impacts upon lateral traction thresholds. And of course, varying weight distribution, as a result of changing fuel tank levels, passengers, or the number of subwoofers in the trunk, will also impact TLLTD.
LOOK: With all of these things to consider, automotive design engineers are forced to create a more conservative TLLTD. As a result, they intentionally target higher front TLLTD values so that stock vehicles will be prone to understeer-the assumption being that understeer is safer and more predictable for the average driver.
For example, a stock DOHC Saturn is tuned to produce a front TLLTD of approximately 63.4 percent-a relatively conservative target. (But give Saturn some credit, as this is on the aggressive end of the conservative spectrum, especially compared to other front-wheel-drive economy cars.)
As a general rule, an average street-driving enthusiast is probably willing to accept some compromises-within reason-of a more aggressive TLLTD in exchange for better handling. A suitable target is probably a front TLLTD value of approximately 58 percent, a value that is considered aggressive, but suitable for street driving.
