mad-butcher
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| posted on 29/9/08 at 08:15 AM |
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OK I accept the point of moving the top wishbone mounts rearwards, But by how much? and would the extra strain on the ball joints be worth it
Tony
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mangogrooveworkshop
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| posted on 16/10/08 at 07:02 PM |
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Rescued attachment Wisbone.jpg
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IDONTBELEIVEIT
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| posted on 16/10/08 at 07:12 PM |
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CASTOR not CASTER(sugar,holiday resort)or is that caister
Are We There Yet, Are We There Yet!!!!
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Antnicuk
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| posted on 1/1/09 at 11:46 PM |
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I am replacing my lower wishbone bushes with rod ends to make the castor adjustable.
I know to adjust the castor i can slide the whole wishbone forwards or backwards, BUT, If i adjust each rod end in and out, this will twist the
wishbone which will also change the caster, is this an ok method to adjust the castor or does this have another effect?
600 BHP per ton, Stylus Brought back from the dead! Turbo Rotary Powered!
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NS Dev
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| posted on 2/1/09 at 10:58 AM |
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the car, if correctly designed, should self centre without bodges like springs in the rack, which, to even consider using, you must be barking mad.
If it doesn't self centre, either make the upper or lower wishbones adjustable fore and aft, or remake the upper or lower wishbones.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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NS Dev
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| posted on 2/1/09 at 10:59 AM |
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PS as has been said many times before, adjustable mushroom inserts on sierra uprights make no difference at all as you haven't moved the pivot
point at all, the ball joints are still in the same place!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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mistergrumpy
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| posted on 2/1/09 at 01:48 PM |
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If it helps I've just returned from my SVA in the last half hour and I was struggling with self centreing. I inflated the tyres to 30psi and
toed them outwards slightly by eye and it worked.
Remember the car only has to attempt to self centre so the wheel only has to come back a little and not like a standard car.
By the way Wayno, it is caster and not castor see here
You'll notice in little blue writing towards the top too where it redirects you from "castor" 
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chrisg
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| posted on 2/1/09 at 05:42 PM |
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It's caster OR castor - they're interchagable.
You can't just keep adding castor angle to help self centreing - it causes other problems, not least of which is that excessive camber causes
the wheel to "flop" from side to side as the wheel is steered.
The so called "adjustable" mushrom is nothing of the sort. The hole is offset forward to increase mechanical trail and so help self
centreing. It should not be used to adjust camber, as has been suggested in the past.
Trail and castor are related but not the same thing.
Castor can be increased by moving the top balljoint rearward (or the bottom balljoint forward)
Mechanical trail can only be adjusted by moving the attachment points ON THE UPRIGHT.
Therefore using an offset mushroom increases the mechanical trail, not castor, by moving the upper attachment forward to move the centreline of the
upright attachments in front of the axle centreline.
Hopefully these sketches might help.
It's facinating stuff isn't it?
Cheers
Chris
Note to all: I really don't know when to leave well alone. I tried to get clever with the mods, then when they gave me a lifeline to see the
error of my ways, I tried to incite more trouble via u2u. So now I'm banned, never to return again. They should have done it years ago!
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MustangSix
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| posted on 5/1/09 at 02:42 PM |
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One of the things that seem to be misunderstood is that a caster increase is only effective if the car is rolling. While at rest, self centering is
also a function of the King Pin Inclination angle.
Envision how the KPI is at an angle to the axle stub. As the spindle rotates, the KPI causes the stub to move in a downward arc, not parallel to the
roadway, actually forcing the car to rise slightly. The weight of the car pushing against this arc tends to pull the spindle back to center.
This effect is noticeable at both rest and while moving. This is also the reason that you can get a self centering effect even on a car with negative
caster, which was common on many cars in the 50's and 60's.
If you increase negative camber, you can get a more pronounced arc from the stub axle, increasing the self centering at rest, but only to a limited
degree.
[Edited on 5/1/09 by MustangSix]
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