Why is my 944 shaking so badly?
11-18-2003, 03:48 PM
#1
Burning Brakes
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Why is my 944 shaking so badly?
I went to visit a body shop this morning to get an estimate on having my 931 nose panel painted and installed on my 944. Now, I've done a ton of work on this car. Installed an S2 engine with new engine mounts, did brakes, wheel bearings, all new suspension components down to the strut mounts and caster mounts and steering rack mounts, shocks, struts, axles, ride height set, aligned, new Michelin Pilots on 4 perfectly straight phone dials. So life is good and the car is cruisin.
I talk to the guys and arrange when I'm going to drop off the car and pick it up, then leave. I get on the highway and as I come up to speed, the car starts this rhythmic high speed shaking. And the faster I go the worse it gets. So I start scouring my brain - I wonder if I picked up a nail and one of my new Pilots is now flat. Did I get a bum wheel bearing? Did a couple axle bolts back out and now a CV shaft is loose? Did I throw a wheel weight? The shaking is totally road speed dependent. I slow down and the shaking subsides a little but is still quite noticable. So I pull over.
Typical day with the 944 right? Just when you think you've got the car in good shape some new problem surfaces. I look at all the wheels, none are flat. Quick glance underneath and everything looks OK. So I get back on the road and the shaking is even worse.
So as I start transforming into this guy:
It suddenly stop. The car smooths out and I'm sailing along perfectly smoothly again.
It was the road surface. It had some bizzare bumpy pattern on it. It had nothing to do with the car at all.
For once.
Bryan
I talk to the guys and arrange when I'm going to drop off the car and pick it up, then leave. I get on the highway and as I come up to speed, the car starts this rhythmic high speed shaking. And the faster I go the worse it gets. So I start scouring my brain - I wonder if I picked up a nail and one of my new Pilots is now flat. Did I get a bum wheel bearing? Did a couple axle bolts back out and now a CV shaft is loose? Did I throw a wheel weight? The shaking is totally road speed dependent. I slow down and the shaking subsides a little but is still quite noticable. So I pull over.
Typical day with the 944 right? Just when you think you've got the car in good shape some new problem surfaces. I look at all the wheels, none are flat. Quick glance underneath and everything looks OK. So I get back on the road and the shaking is even worse.
So as I start transforming into this guy:
It suddenly stop. The car smooths out and I'm sailing along perfectly smoothly again.
It was the road surface. It had some bizzare bumpy pattern on it. It had nothing to do with the car at all.
For once.
Bryan
11-18-2003, 04:43 PM
#6
Nerd Herder
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Dan- Got ya Bubb Rubb on!!
It's also possible that the former nail hole (now fixed) caused a tread separation- or bubble in between the tread and the plies..
Spin balance would make this stick out like a sore thumb.. You would also have strange treadwear after a while.
It's also possible that the former nail hole (now fixed) caused a tread separation- or bubble in between the tread and the plies..
Spin balance would make this stick out like a sore thumb.. You would also have strange treadwear after a while.
11-18-2003, 05:36 PM
#7
Burning Brakes
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Yes, this is all good information, and I thank you.
But there's nothing wrong with the car.
Right after I got out of that section of road, the car went right back to driving smooth as glass. And it's still fine. There are no problems with the wheels or tires or anything. It just struck me how the 944 has conditioned me (I should say "us" by the posts on this thread) to automatically assume that whenever something weird happens, something on the car has once again gone south. Which is usually the case, actually.
Except this time. It was the road surface. And it was just a pleasant surprise to find that it wasn't the car's fault.
For once.
Bryan
But there's nothing wrong with the car.
Right after I got out of that section of road, the car went right back to driving smooth as glass. And it's still fine. There are no problems with the wheels or tires or anything. It just struck me how the 944 has conditioned me (I should say "us" by the posts on this thread) to automatically assume that whenever something weird happens, something on the car has once again gone south. Which is usually the case, actually.
Except this time. It was the road surface. And it was just a pleasant surprise to find that it wasn't the car's fault.
For once.
Bryan
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11-18-2003, 09:42 PM
#11
Burning Brakes
Urrrrrrrr you wanna start takin more water with that malt Bryan hee hee
It was probab;y the ruts cut into the tarmac by the trucks. The 944 ihas a pretty wide track and the front wheels were probably fighting each other trying to jump out of the ruts
It was probab;y the ruts cut into the tarmac by the trucks. The 944 ihas a pretty wide track and the front wheels were probably fighting each other trying to jump out of the ruts
11-18-2003, 10:03 PM
#12
Three Wheelin'
Could have been mud or other junk on one side of one or more wheels. Tire would be out of balance until it dried and fell off. Dead cats can also have this effect.
11-18-2003, 10:15 PM
#14
Instructor
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I have Michelin Pilots on my car too and I notice the ruts in the road quite a bit. I think the tires are really sensitive to tracking. And just like you, when I get on a nice fresh flat stretch of road the problem disappears. Its gotta be the tires and road surface issue.
