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Old 07-05-2016, 05:08 PM
Frank Reiner Frank Reiner is offline
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Join Date: Feb 2011
Location: Modesto CA
Posts: 2,705
Originally Posted by 97 SL320 View Post
There are programs to calculate steering and front suspension locations. The problem can be getting an accurate measurements of the existing car. Have a look at some oval track racing sites.

Rack inner tie rod end center to center is important, matching body length to existing tie rod center won't work.

Ackerman is "toe out on turns" ( outside wheel needs a larger turning radius than the inner wheel ) and is only affected by the angle of the steering arms at the spindles, it won't change by changing the rack.
Originally Posted by Tomguy View Post
Correct me if I am wrong here (I love learning) but if you replace the drag link & tie rods with a RP assembly, aren't you changing the pivot point - therefore potentially changing the Ackerman geometry? Unless the steering angles don't change at all from original, of the tie rods and ends, there's the potential for the geometry to be affected.
In SL's statement is contained the basic Ackerman geometry, as a function of the wheelbase, i.e., if the projected steering arms converge at the rear axle, there is said to be "100% Ackerman".

Tom's question addresses the amount of toe change with steering angle. In the original MB configuration the drag link experiences a small amount of fore & aft movement as it moves from side to side, and a rack moves only linearly, without the fore & aft displacement. If the length of the tie rods is the same in both configurations, there will be slightly greater toe change with the drag link configuration at large steering angles.
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