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Page 53
3LINK SETUP (PARALLEL LINKS IN SIDE VIEW)

NEW

This 3link is a bit different from the one described on Page 20. Yes, it also provides no squat/no rise and it also completely cancels the driveshaft torque problems. The appearance is the big difference. This one takes advantage of a truth which is rarely considered in suspension design. This is the fact that parallel lines intersect at infinity.

Now, you might not have considered that little truth since your high school geometry teacher sprung it on you. You might have had some doubts about it then, but it was true then and it's still true today.

So, if we have 3 links that are parallel to each other, they must also be parallel to a particular line of constant antisquat. In this case, we're going to make them parallel to the line which represents 100% antisquat. This line, as viewed from the side, slopes upward as it passes through the rear tire patch. The slope has the value of the ratio of center of gravity height to wheelbase. In this case, then, the spreadsheet will only provide the upper link offset for driveshaft torque cancellation; It is only necessary that the links have the aforementioned slope.

Since the upper link has the slope described and since it will be in tension as the car launches, the offset must be to the left of the car centerline.

The link strength warnings mentioned on Page 20 should also be applied here.

rear track=

wheelbase =

axle ratio =

effective rear tire radius =

center of gravity height =

weight of rear axle assembly =

total weight =

axle centerline forward to
rear of upper link =

axle centerline vertically to
rear of upper link =

axle centerline forward to
rear of lower link =

axle centerline vertically to
rear of lower link =

ANSWERS:

offset to left (upper link) =

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