Odd Cayman 981 handling trait
Discussion
I changed my nearside coffin arm yesterday to try and sort the pull to the right under hard throtte and move lft under lift off.
It all came apart pretty easily with litle corrosion on the inner most coffin arm location eccentric bolt to slow the job down much. The coffin arm bushings looked fine as did the ball joint. It had exhibited slight creaking after a run, but the other side may have contributed as well.
Oddly I thought, the eccentric bolt didn't match the previously marked position which resuted in my steering wheel being offset. As the track rod hadn't been removed and the tuning fork is a fixed length (it was silent as far as I could tell) it could only be the camber out, thereby altering the toe. With a little faffing I got it measured equally on both sides of the car, making the steering wheel pretty straight and I think the tracking not too far out. It had been set up a couple of years ago my RPM Technik and has been perfect since.
The new arm certainly sorted out the vagueness on acceleration nicely, but I still get a feeling of oversteery floatiness around the right had section of any of Milton Keynes roundabouts. Car turns, in then as power is applied, starts to feel loose. Very strange. Car just gently sways into the right hand turn as I apply power, maybe a hint of lift off floatiness as I suddenly lift off in a low gear.
It's going in on weds to be aligned and the other coffin arm installed, but has anyone else had this behaviour? It's almost as though the tyre is underinflated, but it's not. Vey puzzling.
It all came apart pretty easily with litle corrosion on the inner most coffin arm location eccentric bolt to slow the job down much. The coffin arm bushings looked fine as did the ball joint. It had exhibited slight creaking after a run, but the other side may have contributed as well.
Oddly I thought, the eccentric bolt didn't match the previously marked position which resuted in my steering wheel being offset. As the track rod hadn't been removed and the tuning fork is a fixed length (it was silent as far as I could tell) it could only be the camber out, thereby altering the toe. With a little faffing I got it measured equally on both sides of the car, making the steering wheel pretty straight and I think the tracking not too far out. It had been set up a couple of years ago my RPM Technik and has been perfect since.
The new arm certainly sorted out the vagueness on acceleration nicely, but I still get a feeling of oversteery floatiness around the right had section of any of Milton Keynes roundabouts. Car turns, in then as power is applied, starts to feel loose. Very strange. Car just gently sways into the right hand turn as I apply power, maybe a hint of lift off floatiness as I suddenly lift off in a low gear.
It's going in on weds to be aligned and the other coffin arm installed, but has anyone else had this behaviour? It's almost as though the tyre is underinflated, but it's not. Vey puzzling.
my cars feel livley atm I get over steer in this weather no issue under power.
I guess if you are in for another arm and a geo best to wait till then and see how it drives, it's prob toe in at the rear difference. Or if you are on P zero just crap tyres which have gone hard :-) but now you have a new firm rubber on one side and maybe crap rubber in the other arm so it's never going to track straight under power or brakes now anyway.
I guess if you are in for another arm and a geo best to wait till then and see how it drives, it's prob toe in at the rear difference. Or if you are on P zero just crap tyres which have gone hard :-) but now you have a new firm rubber on one side and maybe crap rubber in the other arm so it's never going to track straight under power or brakes now anyway.
GT_cars said:
my cars feel livley atm I get over steer in this weather no issue under power.
I guess if you are in for another arm and a geo best to wait till then and see how it drives, it's prob toe in at the rear difference. Or if you are on P zero just crap tyres which have gone hard :-) but now you have a new firm rubber on one side and maybe crap rubber in the other arm so it's never going to track straight under power or brakes now anyway.
On 3 month old PS4S's, so they are a well known quantity.I guess if you are in for another arm and a geo best to wait till then and see how it drives, it's prob toe in at the rear difference. Or if you are on P zero just crap tyres which have gone hard :-) but now you have a new firm rubber on one side and maybe crap rubber in the other arm so it's never going to track straight under power or brakes now anyway.
Strange that both arms should have issues at the same time though, although I suppose at 8 years old it's going to have bits getting tired.
I have adjusted the tracking my matchng tye camber to the other side and (cowboy I know) running a piece of straight 2inch batten a 3&9 o'clock on the rims and measuring the gap to front and back of each the rear wheelarches to at least get conformity. I realise that isn't a defintive and accurate measurement, but It's not a mile off as my steering wheel is now straight and runs true under both hard acceleration and braking.
I always try and ascertain the cause of an issue before a fix! This is my fourth Cayman 3.4 and haven't encountered this trait before on just right handers.
Edited by andygo on Monday 17th March 17:23
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