Renaud Bizet

Hello,

I have had a front end shimmy that I have not been able to cure.
The feeling dead center on the steering wheel is very loose/vague as if the steering column had been "untied". Also, I have some vibrations in the steering wheel and it is not 100% speed related.

I had my wheels rebalanced, one was bent and fixed.
I did on car balancing.
I switched tires from Pzeros to Sumi HZIII (not fixed the pb).
My tire wear is even but I might need an alignment anyway.
My Porsche mechanic checked motor mount, suspension, steering rack, etc. and said that it is fine, it is a convertible and should be a bit sloppy anyway.

I disagree I loved the sharp handling of my car and I was having 3 track days a year just to get a better feel for it.
My car is a 2000S with about 50 k miles on it.

Any suggestions as to what to check and/or anybody has a good address to recommend in the Bay Area?

I hate to miss on the driving experience just because the car is not 100% perfect (I am pretty picky but I am sure it can be vastly improved).

Any help is greatly appreciated.

Macster

a mild but noticable vibration that could mimic a shimmy. Very important with these cars to be cold tire inflation pressures right. Buy a good dial tire pressure gage (or digital gage) and use it often.

Not sure about the tires you have on there now. I've run Pirelli or Michelin tires and never had any trouble.

I always have tires balanced with Hunter machine and with load force balacing.

Most bay area Porsche dealers provide this service. BTW, I avoid using independent tire shops.

My experience is they just don't know how to handle these cars. The tech wants to lift the rear of the car using a jack under the engine lifting engine and car with oil sump! Even if the car's lifted by lift most places do not protect the lift points of the car with rubber and this causes the nice underbody paint/sealer to be damaged and can rust a place to get started.

While you might save a few bucks at an independent the quality of the service is sorely lacking. They can handle Ford pickups and minivans but take your Porsche to a Porsche dealer for tires/alignment or Custom Alignment. CA in Mountain View CA.

Used to CA would accept tires drop shipped from Tire Rack then mount/balance tires for you. I always get full alignment when replacing all 4 tires.

Sincerely,

Macster.

Renaud Bizet

Hi Marc,

Nice to hear from you.
Actually my Pzero were always flat spotting and was disappointed with them since they are pretty high end.
The independent I go to is Rite Wheel in Walnut Creek and they only use a floor jack, do not use impact guns, etc. They know how to repair wire wheels and are not your typical chain tire store a la "Big O Tires" for example.
You are right maybe I should just schedule an alignment with Stead and have them rebalance the wheels but they will probably blame the Sumitomos even though I had the same issue with the Pirellis. What I am worried is maybe the vibration as you said is coming from somewhere else since it does not seem to be related to my tires.

Macster

then the problem not likely with tires but with wheels or suspension.

2001, eh? Shocks ok? Over strong area of each front fender press down real hard, try to push car into ground. Let up. PUsh down again. Time your pushes and released to see if you can get car bouncing on its springs a bit.

Stop. If car goes move up or down then reverses again shocks weak. Car should stop moving pretty fast.

Do same on each side, front and rear.

You sure wheels round? No run out when off or on car? Fronts you can raise car corner at time and spin front wheels. If you see wobble either in radial or axial directions wheel bent or cracked/damaged from pothole, curb or just old age.

Take car to empty large roomy parking lot and while heading straight at slow speed, make u-turn. No need to get crazy. Just a nice slow u-turn. Release steering wheel and let wheel center itself. Repeat several times first turning in one direction or the other. If steering wheel doesn't return to same position each time steering rack suspect.

Or find someone to loan you a set of front wheels and see if different tires/wheels alleviates symptom.

Or maybe best thing is to take Eric in service at Stead Porsche for a ride or let him drive and you ride and see what he says.

Sincerely,

Macster.

Renaud Bizet

Mark,

Steering rack and suspension seem fine. You right if I could swap wheels it would be perfect so I could rule out the tire/wheel combination. We had a work on cars day scheduled but it got canceled so I could not do that.
Maybe my best shot is to schedule an alignment at Stead and have them look at it.

Thanks for your help.

bet

First get the alignment from a qualified shop. This could easily fix the problem or at the very least you might find that a control arm or tie rod or something is bent or damaged.

Unfortunately it could be things like worn suspension pieces that are giving the car poor handling. The rubber bushings and items like the ball joints just wear with time. While they may appear fine and/or functional they contribute to the "sloppy" handling. Dampers are another item. In the 993 the factory dampers wore out very fast, and most owners don't realize there was an issue until the dampers were replaced. This concept is not discussed much with the 986 and 996 and I wonder if the same is not true.

Worn suspensions happen over time and most people don't really realize it. In my experience (and this is likely do to my area not really having any higher end shops) most mechanics say the suspension is fine if they look at it and don's see any leaks or obvious tears.

Motobob

I had a 2001 S with exact same issue. I had new tires (Bridgestone Potenzas 960 Pole Positions)mounted by Porsche and balanced and then a full car alignment by Porsche (pre balance most readings were "red" - post balance all readings were "green" with a neutral setup)

As I drove it away from the dealer, it was a new and different car. It is ROCK STEADY as it should be...

My shimmy started right at 75mph but looseness in steering could be felt at all speeds.

Bob 2001 Boxster S

freakdog

Had the same problem with my '03 S. Felt like it was waggling all over the road. Got an alignment check at Porsche, they said it was within spec. Took it in to get new tires from local Firestone, they ran an alignment (same machine as Porsche), showed me the problems, did an alignment, kept the same tires and it was rock solid afterward.

gerrygug

Interesting. I just had a discussion regarding alignment with my independent mechanic. He says the dealers often start out rookie mechanics with routine maintenance and alignment assignments. Could be what happened to you. Mechanic says to go to a good independent tire shop that specializes in alignment if you want it done right.

Macster

which is where I bought car. Tech found alignment off enough to have to adjust.

Afterwards, alignment felt great, car felt great. Too bad car only in my possession 26 days....

Anyhow, I will relate someone on another board had shimmy/vibration problem sort of like yours. Tried everything. Had dealer check out alignment -- more than once -- and each time car handed back with comment "alignment's fine".

Finally this guy took car to another shop, whether another dealer or an indy I can't recall and come to find out alignment not ok. First place just leading him on.

I got a print out of the before and after alignment of my Cayman and could see the differences. I always get one of these printouts whenever I have my car's alignment done.

Sincerely,

Macster.

Renaud Bizet

Hi Mark,

I saw pictures of your car after the accident, what a shame !!!
Glad it was deemed totaled so you can get another one.
I will get the car aligned when work slows down a bit and will report back.

Thanks.