yellowcab
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| posted on 24/2/13 at 06:43 PM |
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MK Indy: Positive Camber Inroll - static test video
I presume I've got the basics right, now its just a case of fettling until it reads the same from bottom to top?
http://www.youtube.com/watch?v=Yr11TIjzywI&feature=youtu.be
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procomp
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| posted on 24/2/13 at 07:22 PM |
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Hi.
That only basic compression. you need to have the wheels static and move the chassis in roll and compression.
IE. replicate what happens during cornering.
Cheers Matt
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Davegtst
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| posted on 24/2/13 at 09:42 PM |
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Is it possible to get it right without changing the mounting points?
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britishtrident
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| posted on 24/2/13 at 11:08 PM |
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quote:
Originally posted by Davegtst
Is it possible to get it right without changing the mounting points?
It is the wishbone mounting points and/or relative wishbone mounting lengths that define it. Basically the wheels have to go into negative camber
in bump and positive camber in droop, when the vehicle rolls in a corner this compensates for the roll angle of the chassis but the gained
cornering grip is traded off with traction/braking braking.
Loads of good books about suspension design that will teach you about roll centres and camber gain.
[Edited on 24/2/13 by britishtrident]
[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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MK9R
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| posted on 24/2/13 at 11:10 PM |
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As matt says it doesn't really prove anything as not showing chassis in roll. You are also comparing the full range from full droop to full
compression and not looking at the set up compared to normal ride height and the limited amount of travel you will actually get during cornering. For
example The fury only actually has about 30mm of droop and 55mm of compression at the rear once the springs, dampers and ride height is set
[Edited on 24/2/13 by MK9R]
Cheers Austen
RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk
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umgrybab
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| posted on 24/2/13 at 11:37 PM |
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quote:
Originally posted by yellowcab
I presume I've got the basics right, now its just a case of fettling until it reads the same from bottom to top?
http://www.youtube.com/watch?v=Yr11TIjzywI&feature=youtu.be
Generally, for race tuned suspension, you would want to gain negative camber as the suspension compresses. Examining the rear right hand wheel as in
the video your camber should become more negative as the suspension compresses. Picture a fast, left hand turn. The rear right hand suspension would
compress when in a left hand turn, when the car is leaning to the right. This lean also causes a transfer of weight. Now more weight is on the right
hand side as well, meaning more of your traction is dependant on the right hand wheels. Sticking with the rear right hand wheel as in the video,
picture the way a tyre would deform when loaded laterally during a hard left hand turn. The tyre would be bending to the left like this /___/
crudely illustrated. Now if the camber would remain parallel to the body of the car (or at 0 deg camber throughout its motion) as in the first part of
the video, the wheel will also be leaning to the right and the tyre will be skewing even further and maybe even leaning on the sidewall a bit
(allowing less lateral traction) as the inside edge would start to lift. Now if the wheel was given a bit of an opposite lean when the suspension is
compressed (negative camber), the tyre would now be able to be have a larger contact patch as its skewing and lifting would now bring it in line with
the pavement allowing more traction. You wouldn't want this negative camber at all times as it would wear heavily on the inner edges of your
tyres and under slower cornering conditions you would not have as large of a contact. So a suspension should be designed to gain negative camber as it
is compressed. The amount can be determined by your centre of gravity, roll centre, spring rate, damper rate, tyre compound, ....... it is never
certain but it can all be calculated and compromises made for each factor.
On a sort of seperate note, I don't think you can use the upper hole in your uprights for the a-arm anyway, the damper mounts there IIRC.
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