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Rick Ehrenberg -

If you are referring to the same one I saw, the chart showed almost triple the bump steer, which coincided pretty well with the tests I made years back.

I was, and still am, dead set against this swap. I hate bump-steer...I like to drive fast on lousy roads!

There are lots of cars that perform pretty well with less-than-perfect suspension / steering geometry. In fact, virtually every design is a compromise. I just fail to see the rationale behind a deliberate downgrade, esp. when the correct parts are not hard to procure.

One of the first years I ran the One Lap of America in my Valiant, two guys - great guys - from western Canada showed up in a pink Charger. They had the tall knuckles, calipers swapped, and I noticed the brake hoses were way too short and/or misrouted. I helped them fix that before the event began.

They claimed that the car had "perfect alignment". And it seemed fine on the highway sections. But on the track, they spun the car, went off, etc., repeatedly. I've always wondered how much of their grief was due to large amounts of bumpsteer.

While I have no idea whom the guy is who did the measurements, presumably, since he was (I'm told) trying to build a case for the tall knuckles, it stands to reason that if it was fudged, it would been fudged in the other direction!

Picture an imaginary knuckle where the upper section had been made, say, 10 inches taller (also see diagram way up in this thread). Nothing else changes. Now the UCA is at a bizarre angle (no longer approx. perpendicular to the steering axis (ball joint axis), and the top of the knuckle moves in and out along what's now a crazy arc that moves the upper ball joint way in and out from jounce to rebound. Camber changes, bigtime, right? And what happens to toe during the travel? Ta-dah!

In another everyday example: Go get your front end aligned. What's the last adjustment they make? Right! Toe! That's because ANYTHING that changes camber will change toe.

Chrysler's engineering credo for these cars (published) was:
"...at some acceptable caster / camber setting, the amount of toe change can be set or corrected to zero which will yield an ideal toe patten.”

Why screw with that? While there are zillions of instances where aftermarket parts far surpass OEM stuff (and the reverse is equally true!), there are no re-engineered aftermarket knuckles – only ones where the spindle has been moved. Jeez. These cars had MUCH better - DEMONSTRABLY better - geometry (not to mention torsional rigidity, unsprung weight, strength, etc.) than their contemporary competitors. Why screw that up?

I’ll give somebody (or everybody) else the last word. I’m done!

Cited HERE

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