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Old 03-04-2014, 10:37 AM   #1
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Ideas identifying a wobble of sorts

So, driving my 00 Boxster S on a flat smooth surface, seems to ride fine.

When there are imperfections in the road however, it seems that I get a TREMENDOUS amount of steering feedback through the steering wheel. Almost a reverberation.

I bought the car with many updated suspension pieces...dont know specifics, but some bushings etc.

The car has 115k on it, original struts, the steering seems tight, I mean there isn't slop in it, the car doesn't wonder on the road.

I did have the wheels balanced hoping that was it, but it made no difference.

Any ideas? or common problem areas?

Thanks!
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Old 03-04-2014, 10:54 AM   #2
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Jack up the front end on both sides and grab the wheel by the tire at 12 and 6 oclock and see if there's any vertical play in the wheel. Then ask a friend to get in and hold the wheel while you do it left to right at 9 and 3 hand position.

If there's any play whatsoever, your bearings are probably shot. At 115k, the car is certainly overdue for wheel bearings.

Another way to see if the wheel bearings are worn out is to spin the wheel and listen for clunking and grinding and general noise coming from the bearing, whose ballbearings are crushed or worn down to nothing by now.

It could be your tie rods (inner or outer) or your steering rack... holding the wheel straight while a friend moves the steering wheel might show you some play in the steering you can't achieve on the open road behind the wheel.

It could also be your struts... those are old.

Hope this helps!
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Old 03-04-2014, 11:23 AM   #3
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Mine does that too. 2004 S with 72k miles. First started when I got new tires put on last January (Pilot Super Sports). Had the wheels balanced 3 times over 2 months to no effect so I just used the lazy method and learned to deal with it.

It drives dead straight, no pulling or directional shimmy, just a steering wheel vibration and only over 65ish mph. It isn't constant though I won't notice it for a while and then it will come back as usual. I have noticed that it is most apparent when the car is cold / it is cold out in general. Road imperfections do exacerbate it though.
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Old 03-04-2014, 12:18 PM   #4
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Good tips Randall...thank you. Although I ve had bad bearings on other cars and would recognize the howl...nothing here.

535...mine is pretty much all the time...the bigger the road imperfection the more wobble...

I was leaning toward the struts myself...just because it "feels" like the reverb of what happens to cartoon characters when then are inside a bell and get hit.

Why I use that as my analogy...it just came to me. Weird.
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Old 03-04-2014, 07:29 PM   #5
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If it happens when you hit bumps it may be the engine mount, if that engine gets moving around it can make the car feel squirrelly. Mostly in the back end but that could cause feedback through the steering as well.

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Old 03-05-2014, 04:45 AM   #6
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I'm going to call it shocks. When they lose their damping and rebound control, the tires can "dribble" like a basketball over bumps. That sounds like what you are describing. At 115K, they are certainly a possibility.

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Old 03-07-2014, 03:08 PM   #7
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Smile Reverberations etc

Hi, just had mine in for general checkover as only bought about 3 weeks ago. Similar symptoms to yours. My mechanic is tops, Merc trained + has very, very fast Datsun race car with 1.8 litre, no turbo, 200bhp at back wheels, trick suspension. He knows what he says and does.
Check the sway bar linkages front and rear. Worn joints effect steering/handling a LOT according to him. Reasonably cheap fix, maybe $150 plus labor or DYI. Do f/r, the lot, I am sure you will feel the difference. Good luck, Phil
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Old 03-07-2014, 03:10 PM   #8
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Check sway bar links. Critical to handling and can cause the rattle and clunk on rough tarmac. Phil
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Old 03-07-2014, 03:16 PM   #9
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Bump steer caused by a lowered suspension?
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Old 03-07-2014, 06:14 PM   #10
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It's not lowered and there are no clunks. It's just a reverberation as a vibration is not accurate. If I get a chance I'll check it out thus weekend. I have a little work to do on the 996t first though.
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Old 03-07-2014, 07:09 PM   #11
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Check the alignment, especially the toe.
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Old 03-09-2014, 12:33 PM   #12
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+2 on the alignment. Too much caster can cause a shopping cart wheel effect. It could be too much air in the tires or a loose steering rack ( mounting hardware).
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Old 03-12-2014, 09:07 AM   #13
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This was my car. I had it aligned to stock specs right before sending it down to Stilov in TX last summer to be sure it was good. The shop said everything aligned perfectly

I did replace the stabilizer links and some bushings, but not the shocks. At the mileage it's at (111k when I sold it), she's probably ready for shocks. The Bilstein HD's are recommended as replacements for street use with stock springs.
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Old 03-12-2014, 09:36 AM   #14
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Ya the "feel" is not like a constant wobble. It's more of a reaction wobble. I sort of think it's the shocks too. In my mind while I'm driving down the road I can imagine that is what is happening.
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Old 03-12-2014, 04:56 PM   #15
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There is considerable difference in road "feel" between different toe settings. Even with good shocks and suspension bushings, zero toe feels different to (say) - 2 deg.

When I installed my PSS9's, I had a quick alignment done by a non Porsche shop and initially it was OK on the road, except the car got nervous and twitchy over 140kmh. I knew it wasn't caused by worn suspension parts, tyres or shocks - all new.
So I took it to a Porsche specific shop and they gave me the following setup:

FRONT: Toe = 1,5mm, Camber = -0.6 deg, Caster = +7deg.
REAR: Toe = +2.0mm, Camber = -2deg.

Wih the front toe increased from 0 to 1,5mm the nervousness dissapeared and the car now feels really good at all speeds.
And don't forget that the rear alignment has a marked affect on the cars feel too.
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Old 03-12-2014, 07:02 PM   #16
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Quote:
Originally Posted by Steve Tinker View Post
There is considerable difference in road "feel" between different toe settings. Even with good shocks and suspension bushings, zero toe feels different to (say) - 2 deg.

When I installed my PSS9's, I had a quick alignment done by a non Porsche shop and initially it was OK on the road, except the car got nervous and twitchy over 140kmh. I knew it wasn't caused by worn suspension parts, tyres or shocks - all new.
So I took it to a Porsche specific shop and they gave me the following setup:

FRONT: Toe = 1,5mm, Camber = -0.6 deg, Caster = +7deg.
REAR: Toe = +2.0mm, Camber = -2deg.

Wih the front toe increased from 0 to 1,5mm the nervousness dissapeared and the car now feels really good at all speeds.
And don't forget that the rear alignment has a marked affect on the cars feel too.
I had it set to the factory specs in the shop's database. Either way, had I kept the car, I'd probably be doing the shocks by about now anyway.

To OP Stilov:

I just ordered a set of KW Variant 1 coilovers for my Mini Cooper, and the Cayman Turbo is arriving Friday after next on a set of H&R RSS coilovers. I'll be autocrossing the Mini next weekend and having a trackday in the Cayman the weekend after and can give my take on the highway ride quality and handling of each of those setups at the end of the month.
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Old 03-13-2014, 08:51 AM   #17
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Quote:
Originally Posted by black_box View Post
This was my car. I had it aligned to stock specs right before sending it down to Stilov in TX last summer to be sure it was good. The shop said everything aligned perfectly

I did replace the stabilizer links and some bushings, but not the shocks. At the mileage it's at (111k when I sold it), she's probably ready for shocks. The Bilstein HD's are recommended as replacements for street use with stock springs.
New OE bushings?
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Old 03-14-2014, 05:18 AM   #18
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yeah, for the swaybars. Was chasing down a clunk.
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Old 05-23-2014, 07:26 AM   #19
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I read this thread as was having similar noises. I bought an engine mount I was going to fit and still am. However I thought I would replace all 4 tyres and see if that would do anything to help.

I don't think people appreciate what a set of new tyres can do. Ok I still have the odd noise but the thud and clanking I had going over speed bumps or any slight mark in the road has gone.

New tyres= less noise and creeks ;-)
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Old 05-23-2014, 07:54 AM   #20
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I'd ammend that to say "new good tyres"

My Boxster is running the cheapest Chinese tyres I could find at the moment as she'll be shredding them the next few weekends getting used to the car and new suspension/alignment
Next month they'll be terrible .
A good street tyre will stay good throughout most of its tread range .
These cheap Chinese ones will be terrible and shaking after 1mm of wear
There is also a remarkable difference between tirenoise even on good tyres .
I took the shredded oe tires off my carrera and fitted some hankkook rs-3 and it sounded like all 4 wheel bearings had took a dump while the wheels were off .
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