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C2S Handling

M

Madracer

New member
I've had my C2S for just over a year. Last Autumn I had a puncture in France. To cut a long story short I had to use an odd Goodyear tyre to get me home. Back in the UK I had two new Pirellis fitted to the rear. Driving it home from the fit I thought the car seemed to wander a bit but I was on a newly laid bit of the A14 near Ipswich and pit it down to the road. The car has not been used that much through the winter but now I'm getting out more in it the problem seems to be there all the time. Hold the wheel straight and the car will drift left and right. The tyre pressures are correct. The car just does not feel as planted on the road as I feel it should or indeed as it did before the tyre change.

Any ideas please?
 
Straight up to Chris at Center Gravity! Best money you can spend on any 911 and now you have a really good excuse!
 
As you've done very few miles on the new tyres, I would give it a bit more time really

Check all tyre pressures are correct with an accurate (calibrated) pressure gauge - not one on the garage forecourt. [:mad:]

Put 500 miles on the car and see where you are. Perellis are well known for "interesting" handling when first fitted. (Might be somethng to do with the moulding marks or the releasing agent used.)

Then I agree with Alex, book it into Center of Gravity for Chris to work a little magic.

Regards,

Clive.
 
I think I posted something similar when new fronts went on my car!!
It was a bit of a wild ride for the first 500miles [&:]

garyw
 
Thanks for the prompt replies. I've done well over 500 miles on the rears so think I'll get it checked out at Cof G as I'm taking the car to France for a few months in June....
 
Don't delay then, as I believe Chris currently has bookings well into June.

ORIGINAL: Madracer
Thanks for the prompt replies. I've done well over 500 miles on the rears so think I'll get it checked out at Cof G as I'm taking the car to France for a few months in June....
Click to expand...
 
Don't worry, after a visit to CG you will be fully conversant with all things geometrical. Chris does like to share his knowledge![:D] But if you want a little homework.............[;)]
http://www.simpsonmotorsport.co.uk/uploads/files/SuspensionSetup.pdf






 
Left home today at 0515 for a quick 150 mile dash through the A14 gap to see Chris at C of G...We took the car for a drive and he confirmed what I had said that the car handled like poo....After a couple of hours of his magic and only one small replacement part the car is transformed.. No more wandering and instability...the car is now planted and runs true, confidence is on the build again...If you have any handling issues Chris is definately the man..
Many thanks
 
Excellent outcome [:)] and pleased that the car is handling as is required now [:D]

Mines in next week for a bit of TLC.....[:(]

garyw
 
ORIGINAL: Madracer

After a couple of hours of his magic and only one small replacement part the car is transformed.. No more wandering and instability...the car is now planted and runs true, confidence is on the build again...If you have any handling issues Chris is definately the man..
Click to expand...
No doubt he explained what was the cause of the instability? Can you share it with us? Pleased it's sorted and you trust the car again![;)]
 
In a nutshell the car would wander from left to right on the motorway. The steering wheel was slightly off centre when driving straight. The car felt incresingly less stable the higher the speed became.

Chris found that the Left rear was cambered intowards the centre of the car too much, which was making the rear of the car move to the right over bumps. The fronts were toed out probably due to sag over age. The camber on them was also both wrong. . The toe out was causing instability at the front, which was all leading to a dutch roll effect...not good!

Now the rear cambers and toe are correct, as are the fronts. Chris has also moved the centre of, pressure or turn further forward giving the rear a bit more freedom but not so much as to make it scarry...not a clue how he did that but the whole car feels planted and super responsive without the feeling that its not in contact with the road. At all speeds it can be driven with two fingers, before it needed two hands!!

Hope thats of some help...I learnt a lot while there, Chris does like to impart his knowledge! and now realise how much the correct set up will effect how the car drives.

Le Mans and the French roads here we come!!
 
ORIGINAL: Madracer

The fronts were toed out probably due to sag over age. The toe out was causing instability at the front, which was all leading to a dutch roll effect...not good!
Click to expand...
And I claim my prize.................[:D] See post #9[;)]
 
You may.

It is an aerodynamic effect which swept wing aircraft are prone to. If an aircraft is disturbed in yaw, i.e the tail moves one way or the other, then that causes the wing on one side to move forward and the other to move back. That means that the wing moving forward develops more lift which makes the aircraft roll.
http://aviationglossary.com/aircraft-terms-definition/dutch-roll/
In the worst case scenario the roll/yaw grows with each oscillation until the aircraft becomes out of control. Swept wing aircraft have long had yaw dampers which snuff out Dutch roll before it gets started.


 
We always learn something new here [:D]
I'm booked in for Tuesday [:)] I think its just drop links...

garyw
 
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