It's not a roll center

[BUGGAR]

I was talking with my rat rod builder neighbor about the fallacy in the definition of “Roll Center”, and I showed him a procedure for calculating roll forces (see sketch attached). He looked at it for a couple of minutes then said, “Oh, the suspension linkage on each side is just a compound torque wrench on a big nut located at the center of gravity”. I like his description so I sketched it up as well (also attached).
Any comments?

 

[BUGGAR]

This site is impossible to attach drawings. You will have to use your imagination for the compound torque wrench concept sketch.

 

[dgallup]

Seems pretty easy to me.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[BUGGAR]

I couldn't load the "wrench" drawing.

 

[IRstuff]

The button on the toolbar labeled "Image" with the camera icon allows you to upload gif, jpg, and png images to display images directly in your posts.

You can also use <left square bracket> IMG image_file_link < right square bracket> to display images from the web.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[SwinnyGG]

What exactly is the 'fallacy' you're dispelling here?

 

[GregLocock]

There is an old wive's tale that the car rolls around the roll axis defined by the roll centres. Unfortunately it is recorded for posterity in Carroll Smith's otherwise excellent books.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[BUGGAR]

Here’s the sketch of the compound torque wrench that models the suspension linkage. I made a model in my shop - this is a good tool to feel how lateral tire forces acting through the suspension linkage can affect chassis roll torque.
But is still is not a "roll center".

 

[BUGGAR]

So, I'm checking the Adams Tutorial for their methods of computing suspension geometry related chassis roll, and they have a bit on computing the "roll center". I stopped there.