W.F. Brown- III

Four new tires on the old '48 Plymouth and the low speed wobble problem is now gone. Thanks to everyone who gave suggestions about the possible cause. They encouraged me to look closely at the tires and when I did, I discovered what could have been a catastrophic failure. Again, thanks everyone.

Uniroyal

When I discovered this it scared the crap out of me to think I'd been driving around on that tire.

Right about that!

Looks like I may have found the source of the wobble problem. I had to look closely to find this. Looks like a new set of tires will be my next investment.

I'm beginning to lean towards u joints as being the most likely culprit.

I just got back from doing a little "experimenting" with the wobble issue on my '48 Plymouth. I discovered I was wrong about it stopping once the car had sufficiently warmed up and had been driven for several miles. Previously, the wobble problem was noticed when I started the car and pulled out of the driveway. What I learned today was that when I first pull out and begin going through the gears, I am moving rather slow (the way the drive enters into the highway plays a part in this). However, after any other stop, when starting out I tend to go through the gears much faster and build speed much quicker. So, what I did was to pick a nice long and secluded straightaway and do some experimenting. All this was after the car had been driven several miles and the motor, tires, etc. were sufficiently warmed up. I discovered, when just barely creeping along in first gear the car had a distinct wobble (real distinct). There is no "shimmy" in the steering wheel, however. With tut the clutch in and still just barely moving, the wobble is still there but not quite as bad as under power. As the speed increases and as I move up through the gears the wobble disappears (or at least is not noticeable any more). I repeated this process several times with the same results. The slower the speed (like down to almost a crawl), the more the wobble. The faster the speed, the less the wobble until it is gone. From this experiment, I would think that should discount a "flat spot" on the tires. The motor/transmission mounts have been mentioned, but I would think that if these were bad it would show not only when moving but when stopped and the motor revved. The driveshaft issue might be a problem, but I would think the faster it was moving the greater the vibration would be (I could be wrong about that). The kingpin issue is something I don't have a clue about, and don't have the resources to check myself. Given all this, any further ideas? I just got back from doing a little "experimenting" with the wobble issue on my '48 Plymouth. I discovered I was wrong about it stopping once the car had sufficiently warmed up and had been driven for several miles. Previously, the wobble problem was noticed when I started the car and pulled out of the driveway. What I learned today was that when I first pull out and begin going through the gears, I am moving rather slow (the way the drive enters into the highway plays a part in this). However, after any other stop, when starting out I tend to go through the gears much faster and build speed much quicker. So, what I did was to pick a nice long and secluded straightaway and do some experimenting. All this was after the car had been driven several miles and the motor, tires, etc. were sufficiently warmed up. I discovered, when just barely creeping along in first gear the car had a distinct wobble (real distinct). There is no "shimmy" in the steering wheel, however. With tut the clutch in and still just barely moving, the wobble is still there but not quite as bad as under power. As the speed increases and as I move up through the gears the wobble disappears (or at least is not noticeable any more). I repeated this process several times with the same results. The slower the speed (like down to almost a crawl), the more the wobble. The faster the speed, the less the wobble until it is gone. From this experiment, I would think that should discount a "flat spot" on the tires. The motor/transmission mounts have been mentioned, but I would think that if these were bad it would show not only when moving but when stopped and the motor revved. The driveshaft issue might be a problem, but I would think the faster it was moving the greater the vibration would be (I could be wrong about that). The kingpin issue is something I don't have a clue about, and don't have the resources to check myself. Given all this, any further ideas?

This just started a couple weeks ago, so I haven't really done anything yet (other than pay close attention to see if I can determine some kind of "pattern" for the wobble). After these suggestions, I plan on trying the carpet scraps under the tires first. If that doesn't work, then rotating the tires. Hopefully, I can rule out the "simple" fix (inexpensive fix), before moving on to having a mechanic check it out.

The problem only started a couple weeks ago. Nice, dry and warm weather. No problems before, even during the extreme cold we had this winter.

I've had this car for six years. The tires are the same ones that were on the car when I got it and I park it in the same place as I have for those six years. The wobble just started a couple weeks ago.

Will do. Thanks.

The car sits in a dirt floor garage, but I'll try the carpet idea. However, if it actually was a tire with a flat spot wouldn't I feel that in the steering wheel?

They are bias ply tires, but I don't think the car doesn't stay parked long enough to create a flat spot.

Something new has started with my '48 Plymouth Sedan. When starting out, the car wobbles like one of the tires are out of round. After just a short distance and after up to speed, the wobble disappears. Once the car has warmed up, no more wobble even at low speeds. There is no shimmy or vibration felt in the steering wheel. The tires are properly inflated and show no signs of wear. Any ideas?

I plan on doing that. It had to go somewhere.