cds72911

Porschetech3

^^^ cds72911 is right, the 1mm wobble at the flange will be 5-6mm at the tire tread. Jack the tire slightly off the ground and set a soda can next to it,spin the tire and measure the wobble. ANY measurable wobble will cause steering shake.

tomcat

How many miles? The tt and C4S AWD cars seem to have a lot of problems with front wheel bearings.

Unless really bad, I think it is difficult to check wheel bearings by the typical shaking of the wheel. IIRC, you may be able to check for roughness while spinning the hub without the wheel.

You need to be careful when installing the lug bolts with spacers. Holes need to be lined up perfectly and lugs need to be seated properly. I use anti-seize on the mating surfaces which helps with hole alignment (i.e., slides easier). I am a little suspect with the spacer not being flush with the hub radial surface. Maybe consider what was already mentioned and see if the vibration exists without the spacers. If if disappears, maybe you need to get different spacers.

dan_189

As an FYI factory spacers are 5mm and they also have two screws to hold them in place.

sixfiveoh

I'll give this a shot, good idea with the soda can trick.

103k, and from what I can see from the limited service records I have, all of the original suspension components.

There are 2 screw holes on the spacers for those "helper" screws that are on the hub, but I don't have extended screws for them, and I contacted the owner at motorsport-tech who said they're optional to use and wouldn't throw off the balance if I don't use them. For what it's worth he's offered to send me another set of spacers if they end up being the issue, but I'm going to go through and check some of these suspension things first.

tomcat

I seem to forget a lot of details these days. I have the same spacers for my rear winter wheels (don't remember the size). And my spacers aren't flush with the radial edge of the rotor (not hub) either. I never had problems with vibration from the spacers.

From what I gather, front bearings don't last 100k (mine didn't). To check the wheel bearings, you may need to remove the rotor to spin the hub to see if moves smoothly. But I don't think you mentioned where the vibration is coming from.

sixfiveoh

Porschetech3

If you swapped the spacers left to right and the problem stayed on the same side , it's not your spacers, it's your wheel, it's bent and the spacers is just exaggerating the issue..BTW, how much is this measurable wobble? Did you measure it ?..To confirm swap wheels from left to right and re-check. If the problem moves with the wheel then you'll know.

Porsche wheels are very prone to bending after hitting big potholes, have seen hundreds of them bent. IF not bent to bad a good wheel shop can fix straighten it.

Worn suspension bushings/control arm bushings will not cause the wheel to wobble just by spinning it by hand..

ANY looseness in steering/control arms/shocks/bearings will make it difficult to control the wheel and could cause a wobble especially after hitting bumps.

911Syncro

It seems like spacers place the wheel off-center with respect to the bearings. So even if there was no wobble, the wheel center is now no longer aligned with the center point of the wheel bearings, which can cause forces on the wheel bearings to be slightly greater. I guess that is one reason I have always been suspicious if spacers can create new problems.

cds72911

It sounds like you may not be super familiar with the system, and you might benefit from taking it to a Porsche specialist? Rather than throwing parts at the problem, you might be able to narrow the replacement parts if a pro did the work. It might save you money in the long run.

DBJoe996

Are you sure that it is not your "brand new" tires at fault? What brand of tires? You can check wheel trueness with a simple dial gauge and stand. Don't even have to take the wheels off, just jack up that side so you can spin the wheel with a dial gauge on the rim. That will tell you whether it is the wheel, tire or in the end, something else. Wheels and tires should not wobble.

sixfiveoh

As stupid as it sounds, I didn't check if the problem followed the spacer to the other side or stayed with the wheel on the passenger side. After I came home from the test drive still experiencing wobbles, I called an alignment place and set up an appointment out of frustration and put the tools away. It does make sense though that if the wobble is there by hand, the suspension components wouldn't be the issue as they're not even under load.

The measure was maybe about 2-3mm in wobble on the passenger side, maybe 0.5mm if any on the drivers side.

Could it be a bearing issue? Do bad bearings spin wobbly?

Fairly sure it's not the tires, as I swapped my old wheels back on that had never given me problems pre-spacers and experienced the same wobble with them. The new tires are Sumitumo HTRs. In any event, I set up an appointment with an alignment specialty shop to diagnose the issue this Friday. Tried to get away with being as cheap as possible on this one, should have known better

qikqbn

I had a similar issue. The farther you push out the wheel from the hub with spacers the more pronounced any imperfection or deflection from road services you will feel through the steering.

I would definitely check to make sure the front wheels are "true" with no bends and balanced. The quickest way to do this is to ask a tire shop to spin it on their balancing machine and observe it at speed. Bends in the wheel can be both up and down from hitting a pot hole, or side to side.
Once that fairly easy and low cost variable is eliminated, then I would move to the suspension. Replacing worn out suspension bushing is what solved my issues. I not only had a bad wobble due to adding spacers, but was developing a wobble under heavy braking. Felt like my rotors were warped, except they were brand new.
I finally replaced my track control arms (coffin shaped), lower control arms ( Y shape fork), sway bar link, sway bar bushings, and inner/Outer tie rods. This solved all my vibration issues and the steering/control felt awesome. Like a brand new car! With 100k+ miles on your car and 14+ years old. All those bushing are seriously worn out or dried up. I would seriously consider swapping out those front suspension parts. Not cheap, but Made a really nice difference in the steering precision and steering tightness. If you plan on holding on to the car for a while longer... might be something to consider.

jbse39

I have vibration issue on my 02 C4S (front drive disconnected) as well. I have new suspension installed all around at 107000 miles and the vibration did not go away. My front control arm bushings were fairly worn, according to shop that looked at it. The car has 5 mm on the front and 15 mm on the back, I think. I will be removing them and will try a different set of wheel/tire set after that. My car vibrates enough to be more than annoyance above 75 mph or so.

Mike Murphy