(The following paragraphs and spreadsheet were developed before I decided to include a discussion of ladder bars. Rather than change them, I would advise that ladder bars be considered as some rather peculiar 4bars, having their rear pivots at the rear tire patches. For the "lateral spacing between link pairs," input the rear track. The angles supplied by the spreadsheet would be the angles, when viewed from the side, of lines drawn through the front pivots and the rear tire patches. There would be no static preloading of the ladder bars. Unfortunately, this ladder bar setup can be achieved only at the time of installation, since the bars are solidly connected to the axle housing.)

4link and 4bar adjustments are typically symmetrical. That is, the right and left side are mirror image. And, we know that, as we increase the angle of the links, we get an increase in anti-squat. The tangent of the angle is equivalent to the slope, or, as my carpenter friend would put it, it's the "rise over run." In terms of the link force, the tangent is the ratio of the vertical force component to the horizontal force component. With 100% anti-squat, the horizontal component is that force accelerating the car forward and the vertical component is the weight transfer. As you probably know, the weight transfer is the forward force times the ratio of CG height to wheelbase. So, it should come as no surprise that the slope of the no squat/no rise line (100% anti-squat) is equal to "h/l," where "h" is the CG height and "l" is the wheelbase.

So, if we have a 4bar and wish to have neither squat nor rise, we would set the angles...right and left side...to that which has a tangent of "h/l."

But, suppose we want a bit more out of the setup. Suppose we want 100% anti-squat AND we also want dynamic cancelation of the driveshaft torque. In other words, no matter the driveshaft torque value, we want to cancel it with the link forces and have enough left over to provide 100% anti-squat.

And, that is exactly what the program below provides. First, the spreadsheet provides the angle adjustment information for a 4bar suspension. If you're wondering about the fact that there are no apparent intersections of link lines, remember that parallel lines meet at infinity. So, link lines that are parallel to themselves and parallel also to the no squat/no rise line can be considered congruent.

Now, it would be nice, with a 4link, if each link pair could be adjusted to be parallel (as with a 4bar). Unfortunately, few (if any) 4link arrangements provide this much adjustment. The right and left side link line intersections (instant centers) of the 4link can be adjusted so that the right side instant center is above the no squat/no rise line and the left side below. The spreadsheet output provides the proper percent anti-squat for left and right sides.

In addition, the individual links of the 4link should not be preloaded.

Finally, there are those who would want to adjust their 4links for changing conditions. It must be realized that there are no performance GAINS available; only performance LOSSES. Equal rear tire loading and no wasteful bobbing up and down of the car is as good as it gets! But, you might be visiting a track where the bite is so good that you're experiencing excessive wheelstands. Then, I would suggest increased tire air pressure and wheelie bar adjustments, but NO change in the link settings.