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Page 21
LADDER BAR (TORQUE ARM) WITH EQUAL REAR TIRE LOADING

NEW

I have hesitated in introducing this page, as I would rather you fabricate a 3link. But, I realize some might wish to consider a transition from their present ladder bar car to a car with some...but not all...of the advantages of a 3link car. So, that which I present here will provide equal rear tire loading on acceleration, but, unfortunately, has the rear end rise normally associated with ladder cars. In other words, there will be no chassis twisting, the left front will rise at the same time as the right front, there will be no binding during street driving, and the ARB can be removed, BUT the rear of the car will rise as you launch.

So, what's the big deal about a little rise? Here's the "big deal": If the shock absorbers never change length during a dragstrip run, they're simply not "doing" anything. This is the case when the car height does not change. This is the case when the instant center is located on the no rise/no squat line. And, this is the case when a 3link is set up according to the spreadsheet on Page 20. Actually, due to the unavoidable rise of the front of the car and the subsequent change in suspension geometry, there will always be a slight drift of the IC location from the no squat/no rise line, but every effort should be made to keep this at a minimum. This means, then, that any time devoted to shock "tuning" is also kept to a minimum. Some racers seem to enjoy the challenge of finding shocks that will improve the performance of a car that is "acting up" at launch, but, personally, I prefer one that simply "goes," so I would never fool with a ladder car, knowing that rise is unavoidable.

So, if you have ladder bar car, you might consider the following. But, be certain that the ladder bar that remains is stout enough to carry a DOUBLE vertical load. In other words, it will be carrying the vertical load that was once carried by BOTH ladders!

The ladder will be on the right (US passenger) side. On the left will be a single link. The link will have a rear pivot point directly below the axle. The front pivot point will be in symmetrical agreement with the ladder pivot point. As with the 3link, there will be unequal loading during a braking "panic" stop. To avoid this, another link, directly above and pointing at the front pivot of the lower link and carrying only compressive loads (bottoms out while telescoping), would solve the loading problem. As pointed out with the 3link, this additional link is not neccessary, but is probably desirable.

link to ladder spacing =

rear track=

wheelbase =

axle ratio =

effective rear tire radius =

center of gravity height =

weight of rear axle assembly =

total weight =

axle centerline forward to
ladder pivot point =

vertical distance from track surface
to ladder pivot point =

ANSWER:

track surface vertically
to rear of link =

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