[Fot] Hard cornering

[Bill Babcock]

No, radius rods keep the axle from shifting forward and back on the springs,
panhard bars prevent lateral movement. The purpose of radius rods and panhard
bars is to provide a stable platform to optimize the suspension and steering
from. By themselves they do very little for handling with a car as far from
good racing suspension design as a TR3/4. But if you get everything else right
they become critical. When the radius rods on Peyote break or get otherwise
disconnected the car handles like crap.

There is no recipe for suspension that will make a TR handle as there is for
modern cars which generally don't have fundamental design flaws. The cheapest
econobox has a rigid platform, no bump steer, camber and camber gain that is
optimized for the recommended tires, no spring tramping, and a precisely
designed amount of understeer to keep Mom out of trouble. If you want to race
one of those cars you buy the parts package that EVERYONE knows works, install
it properly, bolt in a roll cage and you're set to spend some real money
moving from the back to the front. But your car will handle as well as it can
for the given platform.

Our cars are not so simple and the recipe and results depends on the chef. The
way these conversations progress, talking about individual elements instead of
a package, is a clear indication that it's art rather than engineering. If you
wanted to take a more engineering approach you'd get the platform stable
first, then apply core engineering principles to make the car steer and handle
at high speed. The art approach works just fine, but focusing on blueberries
doesn't yield a fine pie.

On Aug 5, 2010, at 7:42 AM, MadMarx wrote:

> If the radius arm is something like a Panhard rod or a Watts link then it
> seems that most of the European racers don't use them.
>
> Chris
>
> -----Urspr|ngliche Nachricht-----
> Von: fot-bounces at autox.team.net [mailto:fot-bounces at autox.team.net] Im
> Auftrag von Tim Murphy
> Gesendet: Donnerstag, 5. August 2010 16:14
> An: 'Greg "Lunker" Hilyer'; 'MIKE DEWEERD'
> Cc: fot at autox.team.net
> Betreff: Re: [Fot] Hard cornering
>
> FWIW  One thing that Uncle Jack told me about radius rods is that the pivot
> points have to be such that the rods are parallel to the axle such that
they
> don't pull or push on the axle when it moves up and down.  Probably not as
> easy as it sounds to achieve.  They were on our car when we got it and Jack
> said he had tried them on his car and found they really didn't help that
> much and were difficult to setup so he took them off.  We never put ours on
> when we built the car.
>
> Tim