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#Post#: 935--------------------------------------------------
Caster
By: Robin_16v Date: September 16, 2013, 2:40 pm
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Hello folks,
I want to discuss caster. How much positive degree off caster
would be a good starting point for a autocross car runing on
dirt? If you watch Rally car go there about 20 degree? But this
would be to much i gues..?
Who could tell me more about this?
#Post#: 936--------------------------------------------------
Re: Caster
By: Smudge Date: September 16, 2013, 4:13 pm
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What car?
In a mk2 Golf it is hard to get over 4 degrees without cutting
and moving back the top mounts or drastically re designing the
uprights. I'm re designing the uprights ATM and will also push
the front wheels forward in the arch a max 15mm.
My aim is to get ajustabilty up to around 7 degrees caster for
Tarmac circuits.
As you say rally cars have considerably more than this and
altering the uprights alone will not get you much over 7 degrees
so you would need to look at moving the top mounts.
Are you allowed to alter the top mount position? If so make it
adjustable so you can then test different amounts of caster out.
Rally
#Post#: 939--------------------------------------------------
Re: Caster
By: Robin_16v Date: September 17, 2013, 2:55 pm
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the car in case is a scirocco mk2. I will be making some custom
camber plates. The rules will allow me to move the complete
mouting points. But nobody has done this before. First i want to
know in what sort of range i need to be to make it work. I'd
reed some where if you go beyond 6 degree it would be to much.
But a rally car for sure run more then 6 degree.
#Post#: 940--------------------------------------------------
Re: Caster
By: Smudge Date: September 17, 2013, 3:14 pm
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As you say rally cars and drifters run lots of caster i guess to
control dynamic camber when they are on more lock
(drifting/sliding) sideways and need more lock than circuit
racers. ???
Can you measure a rally car to give you an idea of what to start
at?
#Post#: 941--------------------------------------------------
Re: Caster
By: Smudge Date: September 17, 2013, 4:16 pm
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[quote]
Increased positive Caster will also make the vehicle more
reluctant to turn and also increase the self centring effect.
However it should give more mid-corner grip and also better
traction. Some people say you can never have enough, being
realistic more than 10° is not going to win any prizes as after
that it is a law of diminishing returns due to some of it's less
desirable effects. Older FWD hatches may have a little 2-3°
Caster so there is lots of room for modification!
[/quote]
HTH
#Post#: 942--------------------------------------------------
Re: Caster
By: Robin_16v Date: September 18, 2013, 10:19 am
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I had meassured the polo r angle from a picture when its in a
jump on gravel. I would be around 15 degrees. So if we need to
believe that we should need to start around 10 degrees.
#Post#: 946--------------------------------------------------
Re: Caster
By: mitlom Date: September 20, 2013, 12:25 pm
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I'm going to be increasing my caster angle on the race car I'm
building using the balljoint spacer plate as shown in my build
thread. I'm not sure what the actual increase in caster angle
will be but I'm moving the balljoint forward by 26mm ??? I was
kind of driven to this by the design of my bracket and wanting
to pick up on one of the existing balljoint mounting holes on
the wishbone!
#Post#: 1000--------------------------------------------------
Re: Caster
By: Smudge Date: October 14, 2013, 12:05 pm
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I think from memory pushing it forward 26mm will increase it
more than two degrees, which is good! The mk3 16v hubs push it
forward 12mm.
I'm planning on pushing my wheels forward in the arch and moving
the lower ball joint mounting point to the hub forward to
further increase caster, add top mounts and I may get close to 7
degrees. Looking at an Audi A3 stock they have around 9 degrees.
More static caster will result in more dynamic Camber, and the
amount of caster we are talking will not be detrimental in my
opinion. :o
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