Jon Ison
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| posted on 22/10/06 at 04:55 PM |
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Like I said personal choice, but most people that find themselves in an over steer situation and go off, go off on the outside of the corner, why ?
Over correct, the tyres find grip and the opposite lock applied (too much of it) steers them off.
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JoelP
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| posted on 22/10/06 at 05:12 PM |
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the few times that this has happened to me like jon describes, is because you cant take the lock off fast enough once it bits. My preference is for
the quickest possible, with suitable castor to stabilise it at speed.
like in this video, from 40 seconds onwards:
http://video.google.co.uk/videoplay?docid=4844493610789993406&q=sideways+sevens
[Edited on 22/10/06 by JoelP]
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NS Dev
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| posted on 23/10/06 at 08:09 AM |
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quote:
Originally posted by Ratman
0.8 turns lock to lock and 120 degrees lock to lock at the wheels. Thats a steering reduction ration of about 1:2. Am I understanding you right? The
pinion would be about 4 inches in diameter. ???
its about 3" diameter, not sure on the maths but thats around how it measures up! Obviously with shortened steering arms and increased ackerman
the "inside" wheel turns considerably more degrees than the outer one, and the 60 degrees is on the inside wheel.
[Edited on 23/10/06 by NS Dev]
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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Ratman
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| posted on 26/10/06 at 09:26 AM |
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NS Dev, tks for explaining. All makes sense. Just what you need to get that opposite lock on quickly. There is a case to be made that if you are
setting up steering geometry to work well on oposite lock, then you should have negative ackerman. Draw a sketch. With the tail hanging out and
opposite lock on, at this point, do you want both front wheels to be tracking round the same notional center point? If they do, does this give you
better grip and improve steering effectiveness?
MikeRJ made some good points a page or two back. My experience of "twitchness" was not really related to steering ratio, more to hard
front suspension, and the imperfections in the road surface that traffic cause. This causes the car to jumps about a bit in a random sort of way.. but
it is not really a problem once you are used to it. A few experimental quick twists of the wheel will assure you that the car is eminently
controlable, and if you just relax a bit you will find the car doesn't actually bump off course by any significant amount. You will find the
problem goes away completely at some speeds and is never a problem on the track where you are turning, braking and changing speed quickly, there are
no invisble heavy trafic ruts in the pavement and the car aerodynamics seem to damp out minor road surface influences... or maybe it's just that
your mind is on other things. Swapping to a wider front tyre can help with twitchyness. I guess this is because it gives a bit more sidewall
flexibility. You might be able to experiment with this just by swapping your front wheels with the back ones.
[Edited on 26/10/06 by Ratman]
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