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Bill Verburg Bill Verburg is online now
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Quote:
Originally Posted by David Inc. View Post
I love suspension geometry stuff. It makes sense but it's absolutely not immediately intuitive. I'll say that raised spindles and bringing the front end back up a bit has really helped the front end.

For a little more on the concept--the roll center is the imaginary point in which the body tries to rotate (at that axle). The distance between the center of gravity (where side forces are applied) and the roll center is like a moment arm, so the higher the distance between CG and roll center the more torque there is on the body.

With a wild enough roll center you could actually get the body to roll opposite to cornering forces, but everything else would be terrible.

Interestingly, I saw in Formula 1 that at one point Ferrari had a neutral RC/CG at the front end to remove roll entirely. They stopped using it, though, because they were getting a ton of sideways movement at the front wheels under braking which upset grip (the wheels would move away from the body under braking load).
There are 2 types of weight transfer in roll
Elastic: through the springs and shocks
Geometric: through he suspension linkages

The issue w/ geometric is it happens instantly, elastic takes some time as the springs compress, as the roll center is raised the ride becomes more harsh w/ a tendency to hop, F1 cars keep their roll centers low because of this effect

lesson: you want roll center high bur not too high
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Bill Verburg
'76 Carrera 3.6RS(nee C3/hotrod), '95 993RS/CS(clone)
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