Re: Panhard rod

[Richard Welty <rwelty@domain.elided>]

At 04:03 PM 4/7/99 -0600, Tom Mandera wrote:
>Panhard rods usually run from one side of the frame down to the opposite
>side of the axle, right?  I see this *causing* the body/frame to move
>laterally as the suspension cycles!

yes, but it'll be less than if you don't have a panhard rod. a sufficiently
long panhard rod does an adequate low tech job of location; it's good
enough to be pretty standard in heavy race cars like NASCAR stockers and
SCCA Trans-Am cars.

other centering devices, like watts linkages and the notorious Alfa Romeo
sliding block, add a fair degree of complexity; they make sense in some
types of installations, but to get perfect centering takes a lot of work,
and for the racing you're doing, a panhard rod should do just about exactly
what you really need.

one tricky bit in all of this is that you not only want to locate the axle
laterally, but if you're being really anal, you also want to pin the
location of the rear roll center. this later task takes a _lot_ more work.

a good layman's intro to the subject is _How to Make Your Car Handle_, Fred
Puhn, HP Books. i don't know if it's still in print. the other end of the
scale is _Race Car Vehicle Dynamics_, Milliken & Milliken, Society of
Automotive Engineers, which is a graduate level text that unleashes all the
equations and how they are derived. in between, there is a lot in Carroll
Smith books (_Prepare to Win_, _Tune to Win_, _Engineer to Win_.)

cheers,
  richard