Cup wheel saga - GOOD NEWS - I guess

I have now had my new cupwheels balanced again and it seems that the first balancing wasn't in order due to a faulty balancing machine. Also I have replaced my old non original locking wheel nuts with original Porsche items (non original ones were quite heavy). All this has helped A LOT on the steering wheel wobble. Unfortunately it's not completely gone. It still vibrates a bit at 100 to 140 km/h (worst at 120/130).

Therefore I tried the wheels on another 911 and boy am I glad I did. No shaking in the steering wheel! So it means that my car is not in order. Only now I need to find out where. I asked my Porsche workshop if it could be the wheel bearings, but they answered no. It could be the car's wheel hubs although they considered that unlikely.

So now I'm open to suggestions. What else can it be that causes my steering wheel to vibrate? I will soon have a 4 wheel alignment peformed to make sure that everything is correcly adjusted. Do you think that will help?

At least now I know that the wheels can in fact function properly. Instead I have a new problem....

Please let me know what you think - I prefer not to spend a fortune in labor on fault searching.

My 78SC stearing wheel also wobbles a little at the same speed. This seems to be a common complaint. After upgrading to turbo tie rods, the wobble noticably decreased. I also tried OEM lugs instead of wheel locks, balancing the wheels again, replacing the wheels, alignments, steering wheel bushing, brake rotors, wheel bearings, torsion bar upgrades and still a little wobble. I still have to R&R the a-arm bushings, but I can't think of anything else.
As for trying your wheels on another car, perhaps your car has a worn suspension part that allows any wheel vibration to transmit to the steering wheel. The other car may have that same suspension part ins proper working order and thus does not transmit any vibration from the wheel to the steering wheel. I don't know, but just thinking out load. Nonetheless, it sounds as if you could do no more regarding the wheels. Why don't you try another set of wheels your car? If the vibration is still present, it would at least show the problems are not the wheels and you could inspect other inspection components.
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Paul
78SC Targa

Ball joints?

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Clay McGuill '66 912, '97 Jeep Cherokee www.geocities.com/the912guy

Have the alignment shop set up the front toe towards the more positive setting. (more toe-in) This will noticeably stabilize the steering. If you haven't replaced your tie-rods, now is the time to upgrade to the turbo units. You will like the positive and direct feeling.

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Tyson Schmidt
72 911 Cabriolet
92 C-2 Cabriolet

Mikkel,

Have you performed an on-car balance? I have to do this everytime I get new tires; a standard balance leaves my Fuchs shaking like crazy! The on-car balance is the only way to get it perfect. Unfortunately, its very hard to find a tire shop to do the on-car balance. They use a strobe light and a couple of other gizmos.

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-Richard
'84 Carrera Cabriolet
'74 911 Widebody 3.6 Project

Hey Richard. Did you get that ring thing worked out? I'd love to know because I'm still paying!
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Paul
78SC Targa

Hi Mikkel,

I can contribute several possibilities from own experience, P car whise and others.

1) Check your brake disks. Unbolt the wheels, make you a fixture (a photo-stand is nice!), use a micrometer dial or some chalk and find out if your brake disks are out of balance. The disk may be warped and/or have some unequal rust deposits on the lateral side.
(This can be overcome by on-car balancing, but I prefer to find the reason itself.)
2) Check your tie-rods.
a) Check the ball joints for wear.
b) make sure that your tie rods are lined up correctly! I had the symptome, that after repairing one, I missed to correctly align the joint at the steering rack side, resulting in very strange behaviours and wheel wobbling!
3) Worn bushings or wheel bearing. Have you adjusted the bearing play?
4) Make a front wheel alignment (Toe-in, like Braniac suggested). Maybe it's out of spec?

Keep running,

Jens