straight line stability

[jaykay]

I find my the straight line stability of my 2000 S (18" 3 piece sport classics) pretty twitchy when there are disturbances, longitudintal (with the direction of travel) undulations in the pavement.

I seem to recall later model years going through changes in the rear track bars to attack this problem. Has any one fitted later model reat track bars with a good effect?

I had 15mm F and 23mm R wheel spacers on which made the car much more sure footed; perhaps they gave a favorable roll centre change; track change. I had to take them off as I was getting substantial vibrations in the steering and the seat from 110kph to 130kph+. There may a balance/manufacturing problem with them...not sure yet.

[ekam]

Originally Posted by jaykay

I find my the straight line stability of my 2000 S (18" 3 piece sport classics) pretty twitchy when there are disturbances, longitudintal (with the direction of travel) undulations in the pavement.

I seem to recall later model years going through changes in the rear track bars to attack this problem. Has any one fitted later model reat track bars with a good effect?

Did you get a mechanic to check for worn out suspension parts?

Originally Posted by jaykay

I had 15mm F and 23mm R wheel spacers on which made the car much more sure footed; perhaps they gave a favorable roll centre change; track change. I had to take them off as I was getting substantial vibrations in the steering and the seat from 110kph to 130kph+. There may a balance/manufacturing problem with them...not sure yet.

That means your spacers are not hub centric.

[jaykay]

the car has very low mileage; I did have the front track bars changed as the bushing had degraded over time........I assume that everything was checked but I will check the rear for worn items again

thanks for your help

[jaykay]

the spacers were H+R and Eib....high quality centric ones but perhaps they have a machining error somewhere....

[Topless]

Maybe just tires or alignment issues. My car is 11 yrs old with 82k miles and feels just as calm and stable at 120mph as it does at 40. Surprising really. Visually inspect the front suspension for damage or loose bushings and then have someone who knows these cars test drive it.

[sd_boxster]

Not entirely sure I understand the symptom you're describing. The P Zero Rossos that my '03 was equipped with when I bought it would track every line and rut in the road.

Changing the tires (in my case to Yokohama S.Drive) eliminated that nasty habit.