The long, (FAST RATIO) pitman arm we offer is basically the same arm used on the AAR's and T/A's. The stock T/A set-up = long (FAST RATIO) pitman arm and a short (stock length) idler arm. We heard that screws up the Ackerman steering. So we put a car on turning plates to test that, and find out. Turning plates or toe plates lay underneath the front tires and read turning angle for each tire independently as you turn the steering wheel. Ackerman steering, means that as you turn the steering wheel, the inside tire turns about 3 or 4 degrees more than the outside tire so both tires are arching equally giving you ~ "zero scrub". We tested this in 3 different modes: First, short pitman and short idler (ie. Your car, stock), Second, long pitman and short idler (ie. T/A, AAR stock), Third, long pitman and long idler (recommended).
RESULTS: 1) short/short = OK ackerman throughout sweep. Result: 2)long/long = OK Ackerman thru out sweep. Result: 3)long/short = OK ackerman thru right hand sweep and OK ackerman up to about 20 degrees left. From ~20 degrees on out , the Ackerman gets exaggerated to ~10-12 degrees. We do not think this really adds up to very much in your overall performance driving picture, because 20 degrees is a pretty tight turn , more like a parking maneuver than anything else. But, why not get it as good as you can get it? Conclusion, If you can, use the long idler. |
