Very high roll centers

[Pcar928]

If the geometric roll center on a solid front and rear axle car is well above the COG, since there is no jacking force ina solid axle, seems like at first glance it would create a moment that would lean it into the turn. However, without jacking this would mean a compressed inner suspension and decompressed outer. Which would mean more force on the inside tires and less on the outside which makes no sense. So technically in the case of a vehicle with solid axles as the roll center approaches the COG it goes from lots of outward lean to, theoretically, none at COG height and as it continues higher above COG it begins to lean outward again?

 

[patprimmer]

And your point is?

Regards
Pat
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[GregLocock]

Buid a car with solid axkles, and a linkage that indispuatbly places the roll centre above the cg, say with an A frame and a bearing. The springs will behave as you say.

But the wheel forces will not, as you have forgotten something.

Cheers

Greg Locock

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[Pcar928]

hmm, if the car does indeed lean into the turn and the loading is not done through the springs then it must be geometric...

 

[GregLocock]

Brilliant

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Pcar928]

Haha, there are no stupid questions, just stupid people right?

 

[BrianPetersen]

Before you get too excited about this concept, keep in mind the potential for bad side effects. Independent suspensions with high roll centers will always have a jacking component, as you are aware. Solid axle suspensions with high roll centers may or may not have a jacking component (and even if it does, usually it will be a lot less than for independent designs), but still, when going over a one-wheel bump, the geometry will pull the whole axle to the side, resulting in some uncomfortable ride motions (at a minimum).

 

[nobog]

Nothing to do with the above roll center conversation, but shouldn't it be called center-of-mass instead of center-of-gravity? JK