straight line stability - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Topless · 09-21-2009, 09:54 PM

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 · 09-21-2009, 11:21 PM

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.

jaykay · 09-22-2009, 04:04 PM

yes that is part of it ........but there is also a slight wander/dancing on the smooth surface as well even after an alignment...seems to be an early 986 thing where as later rear track bars were changed to solve this.

spacers gave me huge vibrations...???

RandallNeighbour · 09-22-2009, 04:11 PM

spacers will always accentuate any inherent wheel imbalance, even if they're totally round and true.

jaykay · 09-22-2009, 05:03 PM

yes very true......tried that but the balance was fine perhaps I will have to try again..

turbo23dog · 09-22-2009, 05:10 PM

At the risk of stating the obvious, are you sure that the tires are inflated to the recommended PSI? I've seen an under inflated tire on one side cause this on several different cars i've owned.

jaykay · 09-22-2009, 05:32 PM

very good point; yes low profiles are really sensitive to this; they were okay as checked with my gauge...but I will try another

the spacer vibration was quite violent and 110; 130kph so this seem to point to a problem with them rather than a tire pressure differential.

to further complicate this thread I did have a lower rear stress bar put on at the same time!!!?