A business trip to the Yukon recently got my E quite dirty. The highways are good, except for the extensive construction, which made a ton of very fine dust. Got home after 6,200 km (perhaps 4,000 miles) in 9 days, and washed the E off, vacuumed her out, and changed the oil and filter like a good boy.

Next time I drove, it felt like all 4 wheels were badly out of balance. Turns out washing the car had drained all the dust to the inside of the wheel rims, where it pooled like cement at the bottom. Must've been a couple kgs (5 lbs) on each wheel! A better wash job cleared it up.

Here's my '04 E admiring the scenery at a lunch stop.

I've had the same thing happen!

Now, when I've finished with the dirt and mud, I take it to the local quarter wash and high pressure the wheels and wheel wells.

THEN I take it home to baby it.. :roll:

The same thing can happen in wintertime, when snow/ice accumulates unevenly in the wheels.