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Old 06-02-2009, 03:42 PM   #88
Sidecar Jockey
Joined: Mar 2002
Location: Middleburg, Pa. (Snyder County)
Oddometer: 3,995
Originally Posted by Clancy
I have to admit I DO confuse the two myself sometimes
But in the NASCAR situation, when the track bar is raised or lowered, it only moves the roll centre miniscule amounts in order to slightly change a handling situation. In the'build' of the car, the aim is always to get the roll centre (and CoG) low in the frame.
But I think I've got my head around what you're saying about roll couples.
Most will use the term 'ceneter of gravity' and 'center of mass' as being the same. Pretty much true.....but both are different than the 'roll center'.

If the roll center and the center of gravity were on the same plane laterally the weight transfer woudl be in a lateral motion(little body roll).

When the roll center is low (the location of the roll center is determined by suspension geomtry and can be many times below ground level) we get more body roll. The higher the cog is above the roll center the more body roll is induced in a turn.
Again, the center of mass or center of gravity if we want to use the terms together rotate around the roll center. They are not one and the same. :-)

Keepin weigth inside the wheels of the vehicle is usually a good step toward be able to manuver well. weigth bias front to rear and side to side is important and can be a good or bad thing depending upon the situation. This is really getting into a whole different thing though.

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