gtroth

Weird. Been daily driving my beautiful C4 ~75 highway miles per day since September, and has handled perfectly.

One morning, around 10~15 minutes in, I got a pretty severe shake in the steering wheel, so I pulled over to look at what I was sure was a flat front tire. But it wasn't. Drove off and everything was perfect for a few weeks. Second time it happened exactly the same way, same timing too, but that time I did the 'simulated walk around" - waited a minute or two and drove off, everything perfect. Third time, the day after the second, the same.

All three times it was pretty cold (8°F~14°F), first two times were after driving through some snow the night before, but not the third time.

~80K miles on stock original factory MO30. New Michelin Pilot Alpin PA3's 205/50R17 & 235/45R17 (rears 1% larger than front).

Any ideas what might be going on here?

Thanks in advance.

jscott82

Ever seen the movie My Cousin Vinny? You got mud in yer tires.....

Any chance you have snow packed or frozen to the inside of one of your rims?

matt777

That is a tough one to diagnose. I would see if it is speed related ie only at certain speeds or vibrating at all speeds/getting progressively worse. It could be balance or possibly a damaged tire. Either way, an inspection of the tires and suspension/steering mechanism and check balancing the tires would be in order. A good tire balancer/operator can tell if the tire is internally damaged/separating even if the balance seems okay (I've been through this).
Matt

gtroth

Couldn't see any ice build-up. I assumed that was all it was until the third time which saw ~70 miles of dry driving before it acted up. Little warmer today - I'll go take a closer look.

gtroth

re speed related - it has started at highway speed all three times and persists all the way down to stop. Then I can drive off perfectly as if it were a bad dream.

stace

Bad tie rod?? I had one of mine go and it would vibrate then stop while driving. easy to check - raise the front wheel(s) off the ground and see if the wheel shakes when you grab each side of the tire and give it a good side to side rattle. I could actually see the tie rod move slightly in the dampening section of the tie rod.

Steve Weiner-Rennsport Systems

Sounds like ice to me. The reason its gone after you stop and then drive away is that heat from the brakes melted it off. You may not ever see anything,.........

Remember now, these large, low-profiles tires can shake "like a dog sh*tting peach seeds" with the slightest imbalance (1-2oz) so it wouldn't take much to make the wheel shake pretty hard.

That said, it wouldn't be a bad idea to get underneath and check the front control arm bushings for excessive movement, the tie-rod couplers, and tie-rod ends.

helmet155

What condition are your front control arm bushings in?

murfysflaw

Interesting. I've heard of similar symptoms in lifted Jeeps called "death wobble", but it's normally caused not completely taking care of all the things necessary to properly lift a Jeep 3+ inches. Gets lots of things out of alignment and many people try to do it on the cheap. Can't imagine what it'd be on a Porsche aside from what others have suggested with the tie rods, control arms, and finally ice/snow buildup.

CaptainGSR

My left front started shaking at highway speed (+60mph) after a rain storm last year (got caught). Scared the **** out of me! Had to limp home under 60:-(
I had the wheel re-balanced the next day. It was way way off! I still don't know what happened. All the weights were still on....
No problem since.

95_993

+1 on the tie rod or bushing. Everything seems good until u hit just the right bump/frequency for it to start and oscillate.

helmet155

Time for new bushings, maybe tie rod ends...and an alignment following the rear first method...

AOW162435

Don't rule out your front CV joints.


Andreas

gtroth

Jacked her up today. Nothing looks obviously wrong - no play in any components I was able to find (zero play when shaking the wheel L-R, T-B). No loose bolts. All rubber parts look good to me (nothing bulging or cracked).

Oscillations from tie rods / bushings, would they typically stop for the day (or for weeks) when the vehicle stops? And I mean stops oscillating and returns to perfect handling and tracking. Any good ways to test bushings?

CVs, yeah, who knows - fronts are a new world for me. No rhythmic thumping, no excessive play when I grab and shake.

Still thinking ice is most likely. Might be warm for a bit - if it happens then at least I'll have this answer.

Thanks again.

cabrio993

How old are your shocks?

Edit: Never mind..I read your post again. 80K miles on original shocks? If one of your shocks has leaked, your tire will begin to bounce uncontrollably at the first bump you hit at speed. Without a working shock, all you have is a bouncy spring. And with each bounce, it gets worst and worst until you stop.

I'll start by replacing the shocks.