DDK - Die Deutschen Klassiker

Right now it could be anything, wobble has been with the car since before the rebuild. I had new rear tyres fitted last year and had all four balanced at the same time. Which made no difference!

It’s got new turbo tie rods, good dampers, bearings are (apparently) fine but I’m not ruling anything out.

My suspicion is run out on a disc or hub, probably front, as it can get worse when taking a bend at speed on a motorway when there is a bit more lateral load going into the system.

Good luck!
Mine appeared when I fitted my 7" cookies which i ran on the car with different tyres, supper sticky Kumho V70, 50 section for hill climbing.
Wheels are true: DTI gauge true
Discs true with bearings snugged-up tight
Zero play in the front end (rubber bushes everywhere now)
3 day long DIY alignment, might have too much caster as steering is a bit wooden.

New tyres (Dunlop 65 section) fitted and balanced 3 times, all true, 20/32 pressures.

On the to check list was the track control arms and the Bilstein custom dampers that are 26 years old/60K miles. Road manners are impeccable.

However, it all just dissapeared overnight.

Steering wobble was classic tyre balance in nature, about 6mm occillation at the rim.

Daft as it sounds, I had a wobble on mine and all i did was swap the rear tyres with the fronts both side and it solved it. They were worn tyres so it might be that i out them back on wrongly anyhow. Yours are new so don't suppose that would solve it for you, but you never know, might be worth a try

I think coincidently me and gary have the same tyres ( both of us with full new sets ) and both have the same speed wheel vibration on motorways . I've not got around to getting mine rebalanced yet though , but my gut feel is they needed a bit of miles to settle onto the wheel etc. I wont get mine done until the spring though so might be wrong. Previous set of tyres were same make and model and ran smooth but do seem to remember I had similar issues when they were new

My fronts have done about 20k, rears have done 4k, so I’m hoping they are run in

The DTI will feature heavily in the investigation, from tyre (might be lumpy…), to wheel, to disc and hub. Front and back.

And of course another go at balancing wheels as it’s often the most simple things .

markm wrote: ↑Wed Dec 07, 2022 11:34 am Daft as it sounds, I had a wobble on mine and all i did was swap the rear tyres with the fronts both side and it solved it. They were worn tyres so it might be that i out them back on wrongly anyhow. Yours are new so don't suppose that would solve it for you, but you never know, might be worth a try

I think this is a good idea - rotate the tyres, as they say in America (assuming that fronts and backs are identical), to see if it makes any difference...

They aren’t flat spotted are they from being stood in the same position for a long time? This can give a wobble to

During my checks, I stopped the wheels round the car, it made no difference.
Took the rims to be balanced by another tyre shop, found to be out, corrected, problem still there.

Very recently Neil B posted a video where the owner battled through this very problem going to huge detail to have it all running true at the front.
Iirc is was something at the rear!
Go to Porsche video of the day, it is the last video. Worth watching.

markm wrote: ↑Wed Dec 07, 2022 11:34 am Daft as it sounds, I had a wobble on mine and all i did was swap the rear tyres with the fronts both side and it solved it. They were worn tyres so it might be that i out them back on wrongly anyhow. Yours are new so don't suppose that would solve it for you, but you never know, might be worth a try

My guess is you moved the wobbly one to the back where you no longer feel it in the steering wheel.

I have a wobble around 70MPH too. I have had the wheels refurbed and balanced, the disks changed, new tyres and I still have it. I suspect its the tie rods.... A job for the winter. I have 7Rs at the front and 8s at the rear, so can't try the swap, but I don't think wheel balance is my problem. I only have the wobble on the straight, hence I think its tie rod, possibly steering box related.

Paul

That's where I ended up too, rack (original 1973 untouched) and or tie rods, (turbo new in 1992, 60K miles old)

no MoT failures or advisories in 30 years.
Now disappeared on it's own! Makes no sense, but still suspect the rack/rods, but if it has gone away, I'm leaving well alone.

PMNorris wrote: ↑Fri Dec 09, 2022 5:04 pm I have a wobble around 70MPH too. I have had the wheels refurbed and balanced, the disks changed, new tyres and I still have it. I suspect its the tie rods.... A job for the winter. I have 7Rs at the front and 8s at the rear, so can't try the swap, but I don't think wheel balance is my problem. I only have the wobble on the straight, hence I think its tie rod, possibly steering box related.

Paul

If you end up baffled, try shiftng the wheel balancing weights from from outer face to the face nearer the centreline of the vehcle (or vice versa). The wheel can be out of balance at its outer or inner face, and having the weights near the wrong face balances the wheel but the axis of its many moments of inertia around each segment of the cylinder may not be along its geometric axis, giving it an eccentric wobble.

Interesting thought. I'll give that a go.

Many thanks

Paul

hot66 wrote: ↑Wed Dec 07, 2022 12:00 pm I think coincidently me and gary have the same tyres ( both of us with full new sets ) and both have the same speed wheel vibration on motorways .

Could be a centric hub issue. Porsche solved the problem in 1974 by amending the Fuchs wheel and the hub, but you can buy rings (see link below):

https://us.hubcentric-rings.com/

Could well be something like that.

Ultimately the force you feel in the steering wheel comes from the spinning things… be that brake disc, hub, wheel or tyre.