drlloyd
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| posted on 11/5/07 at 12:52 PM |
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Anti-Dive Geometry
I am currently working out the suspension geometry for my kit-car and am wondering if anybody else is using anti-dive geometry? If so, how much are
you using? I was thinking of angling the bottom wishbone by approx. 3 degrees towards the centre of gravity.
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Ivan
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| posted on 11/5/07 at 01:48 PM |
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Have a look here -
http://www.locostbuilders.co.uk/viewthread.php?tid=65564
there are several other anti-dive threads as well.
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kb58
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| posted on 11/5/07 at 03:17 PM |
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Weird, when I looked at this thread title, I saw, "Anti-gravity geometry."
Carroll Smith notes that it doesn't work well because it binds up the suspension joints.
Mid-engine Locost - http://www.midlana.com
And the book - http://www.lulu.com/shop/kurt-bilinski/midlana/paperback/product-21330662.html
Kimini - a tube-frame, carbon shell, Honda Prelude VTEC mid-engine Mini: http://www.kimini.com
And its book -
http://www.lulu.com/shop/kurt-bilinski/kimini-how-to-design-and-build-a-mid-engine-sports-car-from-scratch/paperback/product-4858803.html
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britishtrident
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| posted on 11/5/07 at 03:52 PM |
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quote:
Originally posted by drlloyd
I am currently working out the suspension geometry for my kit-car and am wondering if anybody else is using anti-dive geometry? If so, how much are
you using? I was thinking of angling the bottom wishbone by approx. 3 degrees towards the centre of gravity.
The alternative of tilting both upper and lower wishbones at the same angle is considered a safer bet, because it has less undesirable effects on the
steering geometry.
But with anti-dive a little goes a long way
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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davew823
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| posted on 11/5/07 at 04:22 PM |
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anti-dive
3 degree of anti-dive will probably be way to much. Even heavy America front engine cars normaly do not have that much. I would shot for no more then
one and half degrees. A locost has a much lower C. G. then most cars. DaveW
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drlloyd
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| posted on 14/5/07 at 10:04 AM |
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Thanks for the advice, I have a number of books by Staniforth, Herb Adams, etc that cover anti-dive geometry but there is no indication of how much is
really required. I think I will probably limit it to inclining the bottom wishbone up by 1.5 degrees. 
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britishtrident
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| posted on 14/5/07 at 02:04 PM |
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What you have to watch is that with that arrangement the bottom wishbone ball joint moves forward with suspension movement, which rotates the upright
and has all sort of unwanted effects on bump steer, roll steer, caster angle............
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drlloyd
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| posted on 15/5/07 at 10:12 AM |
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I am aware of that but approx. 3" of suspension travel would equate to only 2mm of forward wishbone movement with a wishbone inclination of 1.5
degrees.
I would not expect to regularly get this amount of travel in my kitcar and I expect that the rubber bushes at the chassis end of the wishbone would
allow the wishbone to move forwards by at least 1mm anyway.
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Doug68
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| posted on 19/5/07 at 05:46 PM |
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I've not been able to find any definitive data at all on what effect this has on stopping distance s for one.
The other thing is that there are all sorts of other transient conditions the vehicle goes through such as braking whilst changing direction, where
the effects of this type of geometry are going to be hard to predict in advance.
Unless anyone can come up with test data such as stopping distance figures or lap times that prove there's an improvement then I'd steer
clear (get it?) of the whole subject.
Its also interesting to note that in the 1980's anti dive was seen as a big issue for motorcycles, after a lot of effort by a lot of companies
the idea has basically been abandoned now as a dead end in development. Bikes now just concentrate on having structurally sound properly valved
suspension, and I think there's a lesson in that.
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