Thumping noise after changing to summer tires

[leegf]

I'll give it a shot. Any idea on the technical reason behind why E30s don't take to tire rotation?

actually, i, too, would like to know -- i've never heard this.

OP, how did you rotate?

[ev87]

On an E30, you are not supposed to rotate the tires. Put the tires back to their original locations.

I'll give it a shot. Any idea on the technical reason behind why E30s don't take to tire rotation?

[dnguyen1963]

On an E30, you are not supposed to rotate the tires. Put the tires back to their original locations.

[ev87]

I'll double check after work, but I torqued the wheels down to 80lb-ft when I installed them. Does that seem about right?

[leegf]

are the wheels torqued properly? just a thought.

[ev87]

Yesterday I put the summer tires back on my 89 325is. This is the same set of wheels that was on the car for pretty much all of 2011 without any problems. The only configuration change was a rotation of the tires, to kill two birds with one stone.

Taking the car out for a test drive after this, I noticed that when turning left starting with the wheel at about half-lock, there is a regular, periodic thumping noise that gets more frequent as I go faster. When turning right, or going straight, all is OK. I checked for anything I could think of - wheels rubbing against wheel-well liners, rocks caught in the tread, and tires having gone bad over the winter, with everything again seeming just fine. It doesn't seem to be brake drag as there's no speed loss associated with the thump. As mentioned, this only happens when turning left, and produces a pretty loud thump sound as well as a bump felt through the whole frame. This also occurs when backing up, but this time, only with the wheel turned right.

Here's a quick video I took in a parking lot to demonstrate: link.

Any suggestions as to what hell this could be? I'm completely out of ideas at this point.