Hi Guys,

Just doing some CAD work awaiting my chassis coming and I have a question.

Looking at different peoples builds, some have the wishbone perfectly aligned so top and bottom are parallel so that the upright is as always at the same angle through the suspension travel.
Others have the top wishbone where when the lower is parallel to the chassis, the top wishbone is angled slightly up.
This would mean as the suspension travels up, the upright would angle more positive camber?

Is there reasons or good and bad points for these?


Cheers,

quote:

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Originally posted by the_big_1
Hi Guys,

Just doing some CAD work awaiting my chassis coming and I have a question.

Looking at different peoples builds, some have the wishbone perfectly aligned so top and bottom are parallel so that the upright is as always at the same angle through the suspension travel.
Others have the top wishbone where when the lower is parallel to the chassis, the top wishbone is angled slightly up.
This would mean as the suspension travels up, the upright would angle more positive camber?

Is there reasons or good and bad points for these?


Cheers,

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As said above, it's a lot more complex/dynamic than that.
Not only does wishbone angle effect it but also they're differing lengths giving different arc's. Neg camber gain is normally desired to compensate for body roll and keep the tyre flat to the road.... but where does it roll... so calculate roll centre... and migration... and there's a lot more.

Thanks guys,

Can you give me a link to the book or its tittle. I can not find it searching on google.


cheers!

as above the short answer to your original question is 'body roll'

If you built it all perfectly parallel you'd get positive camber on one wheel as soon as the body rolled even a fraction of a degree...
but as above working out the "correct" geometry properly is a bit more involved......



I believe this is the book he means:

https://www.amazon.co.uk/Competition-Car-Suspension-Design-Construction/dp/185960644X/ref=sr_1_2?s=books&ie=UTF8&qid=1475139209&sr=1-2& ;keywords=Competition+Car+Suspension

have a look on the for sale section and ebay etc - there are normally a few second hand copies knocking about


[Edited on 29/9/2016 by mcerd1]

On-line suspension geometry simulator/calculator

A very useful tool!