some say toe in, some say toe out.... ahhhh I love forums.

 

Assuming the tire pressures are ok -- BTW my info is the pressures given on the back of the gas filler lid are for a fully loaded car so unless you are carrying 4 people including yourself and their luggage you might want to reduce the pressures by 2 or 3PSI -- and the car has its factory body parts, like the front air dam and rear spoiler/wing -- I'd offer alignment as the reason for the car's feel.

(Oh, I have to also assume the car has proper tires on it -- by this I mean N-rated and of the correct size, etc., and if unidirectional they are mounted in the right direction and so on.)

Have the car properly aligned and be sure you get before and after printout of the alignment settings.

As for alignment settings, I just have the tech throw the factory bog standard alignment on the car and it feels just fine even at high speeds. And I mean high speeds...

 

I don't think I read any question about your tires. What brand, model and age of the tires? I've had that wandering feel before with excellent tires that were a little worn - not to the wear bars. Once replaced, it was perfect. Additionally, as a couple of above posters, I never run tire pressures as high as the recommended. Generally around 4 psi lower for better handling and softer ride.

 

Thanks for the feedback. I bought the car months ago, but did drive it much due to weather. This spring I noticed the issue, but just assumed tires & alignment. First thing I did were the typicals: new correct tires and a four wheel alignment at my local porsche shop. Always had good results at this shop with my 964. But it still didn't correct the problem. My 996tt is bone stock with about 26,000 on it. I'm just getting tired of the 75mph wander and steering wheel shake. BTW I also had the tires balanced twice.

 

steering wheel... shake

a wheel may be untrue.

 

I also thought an untrue wheel could be the problem. I'm going to need to dig deeper. Thanks

 

that would be the next thing i'd check for/eliminate. couldn't live with what you described. good luck!

 

I have found that on roads/highways where the heavy trucks have been and caused slight grooves/tracks in the concrete that the car will wander a little bit on the grooves. No other "wandering" issues.

 

+1, are you sure your car is not tramlining, following truck tracks in the pavement?

Did the P Dealer give you a before and after specs on your alignment? Did you verify the numbers?

Have you tried different roads, highways?

I'd suggest measuring your ride height at Porsche specified chassis measuring points. This is important for high speed stability. Rear should be around .250" higher than the front.

 

https://www.6speedonline.com/forums/...ml#post3976057

See post #9

 

Were the tires road force balanced?


This should detect a bad tire, or a bad wheel. That is if the tech recognizes that having to use say 20lbs of weights to bring a tire/wheel into balance is not normal.


Really, there is a limit/threshold of weight required to bring a tire/wheel into balance that if exceeded should either let the tech know he's not doing the job right, the balancer is off, or the tire or the wheel has a problem that won't ever balance out.


Next I hate to bring this up but I have to question the alignment. I've watched my Turbo being aligned and it is a real job to bring all the readings in and get them on target. Changing/adjusting one setting can cause another reading to go out of spec and more adjustment at another place is required to bring this 2nd reading back into spec.



One can see this watching the alignment rack computer screen graphic as the tech is under the car adjusting away.

The tech will go from adjustment point to adjustment point back and forth several times as he brings the car into proper alignment.


This requires the tech to really know his stuff, and even so it is a time consuming process.


Last but not least the alignment rack must be up to it. I've encountered some pretty sad looking alignment racks at some shops.


Even at some dealers, that have several different brands of cars.


Each brand's service department can have its own alignment rack. But often most of these are really crappy.


Usually though, there is one superb rack in one of the brand's serviced department but it is not located in the Porsche dealer's service department.


So, to use the good rack the Porsche tech has to take the car over to the service area where the good rack is located.


'course this is a heavily utilized resource and almost certainly he has to wait or is otherwise frustrated by the techs of the other brand or brands who work to shut him off from the hardware resource.


So sometimes the old rickety rack at the Porsche dealer service department gets used and with less than optimum results.


The only time I can remember one of my Porsches, the Turbo too, receiving what proved to be a bad alignment -- the rear tires wore out in around 8K miles -- was the time the car was aligned on the old crummy rack (which at the time I didn't know this) and I didn't get a before and after printout.

 

I'm going to take the car back to the shop I had the workdone at for more investigating. It's a reputable family owned shop that I havehad good experience with, plus all work has a lifetime warranty. I just haven'tgot it over there yet. I really don't want to take it somewhere else and pay again;I’ll hold that as a last resort. My Porsches aren't my daily drivers so for nowit is out of site out of mind.

 

you're a tolerant person. mine is sometimes out of sight,.. but never out of mind