Steering Wheel Shake at 70-80 mph?

[manolo]

I have a similar issue and I got under the car and found both lower ball joint boots have cracks/tears in them. I suspect they have been that way a bit and the ball joints are toast. Iplan to install new lower control arms and hope that gets rid of it. I had the wheels checked and they weren't out of balance.

[jhandy]

as someone that has chased down a shakeing that lasted 2+ years, I offer my lessons.

basically anything that rotates needs to be looked at. If the shake is rhythmic and gets faster with speed... it has to be a rotating mass issue.

if it never did it and then you messed with the springs and now it is doing it, I would look at it like something may be loose less likely something bent.

Did they knock off a wheel weight?
all bolts tight?
Spacers?

A ball joint or tie rod damage, it may shake but on and off and not rhythmicly. (ie- not rotating)

My issues turned out to be the spacers.

[WhipE350]

I did all my shocks over Dec and in the end had to have an alignment...it may not fix the shaking, but you really should get one, I was very happy after mine, car was totally different. If you find a good Indy, while they are doing it they can check for anything being lose.

[dirkdiggler]

Whats the average cost for an alignment??

[Gforrest2]

Originally Posted by dirkdiggler

Whats the average cost for an alignment??

I'd like to know that too and can any shop do it? Like your local tire store that advertises $59 alignments or should you go to a Porsche specialist?

[jhandy]

Dirk-
Reading the first post again, It really sounds like something is loose, because of what you said "by holding the wheel it seems to stop"
If it was a bent wheel, or rotor, or axle....you would not be able to fight it. My wheel spacers shook so strongly if you tried to hold the wheel hard, it would shake your shoulders.
try something simple......jack it up take each tire off, and check the axle nut torque, and put the wheel back on correctly torquing the studs.
I bet its either the axle nut or the wheels. Look for missing lead.

Also you should get the alignment specs and bring them to your shop. Brakecheck can align a porsche, but I doubt that they will know what settings to shoot for.

When I lowered mine, the dealer printed out for me target settings depending on how I wanted to drive it and how fast I wanted to replace the tires.

IIRC the choices he gave me where "factory, street/sport, track"

each choice used the tires progressively more. I chose track, and the car stuck to the road, but I went through two sets of tires in 15000 miles. The camber/toe was so aggressive that it wore out the inner shoulders leaving the outer edge 50% used.

I had it reset to factory values, and drive slower, and use much less rubber.

[WhipE350]

I used Eurowerks in Charlotte NC, it was $180. I was impressed overall with their work, I watched the whole thing. It took a while to do so I thought the price was fair. They had an expensive setup just for doing the alignment.

[Klimo]

Have had similar shakes at same speed. New tires and an alignment did the trick. With your recent tire balance sounds like something in your mods. As others have states. Double check everything that was done. gl.