Hey NAM! I've got an '06 MCS that will likely hit 70k miles by the end of the week. I've owned it since new. No accidents, about 15K on the current tires, but I do drive around Chicago a lot so there have been some mega-pothole encounters. Strut towers have a little bit of mushrooming but nothing like some of the pictures I've seen.

It has developed a steering wheel shake and it's driving me nuts. Sometimes it's there, and it's definitely speed variant, but other times the wheel is steady like a rock. It doesn't seem to be related to the road surface and the shake is pretty rhythmical. I was under the car pushing and pulling on all kinds of things, but I can't find any obvious looseness. The lower control arm bushings appear to be in good shape and don't move by hand, although I haven't put a pry bar on them. Any suggestions or areas of concern?

I'm kinda stumped so I figured I'd ask the experts. Y'all were invaluable this weekend when I replaced the leaking t-stat gasket so thanks for that!

 

Wheel balance possibly? I'm sure someone will chime in who may have another possible solution. I actually had a similar problem with my Expedition. Terrible shake at certain speeds. In my case it turned out to be that I had nearly a half gallon of water in each tire from a bad compressor that I used frequently after going off-roading on the beach. However this is probably not the case with your mini. I would check to make sure that none of your wheel weights have fallen off from potholes

 

Based upon your location I bet you have been experiencing some snow/ice over that last couple of months. If you get some snow on the inside of one of your wheels, it will throw it out of balance until it melts/evaporates. It doesn't take much to get the wicked shakes at highway speeds.

 

I initially suspected the balance but it checks out at the local tire shop. I was worried about a bent lip (potholes!) but there is no visible deviation. It's not ice buildup because it's been going on since September or so, and we don't get snow that early.

Man, you guys are fast.

 

The main culprit would be wheel balancing if it's related to speed that you get a vibration. Only other item would be possible warped brake rotors but that would be a vibration anytime you hit the brakes. Can't really think of much else.

 

I had exactly what Helix was suggesting a couple years ago. After some snow buildup in the wheel they felt really out of balance. Cleaning all the snow / ice buildup from the wheel made it go away.

 

Do you notice the shake mostly when you get in and start driving? i.e. after the car sits for a time (like over night or even during the day at work)? If so, it might be your tires getting "flat spots". I had a set of Kumho tires on my '06 Cooper that did this....especially after they had worn a bit. They got so that if the car sat still for more than a couple of hours, the front end would shake for the first couple of miles on the highway until the tires heated up and rounded out again. Just something to consider.

 

I would also look for uneven tire wear. I noticed a slight vibration while under acceleration at certain speeds and will be looking at wheel balance, hopefully its a quick easy fix

 

If the vibration is rythmic and speed dependant, then something that rotates is out of balance. It COULD be part of the drive train, but that is highly unlikely. The only other culprit is the tires. Someone mentioned flatspotting above . . . that could be an issue. But most likely it's tire balance or uniformity. Did your local shop do a regular spin balance or a road force balance?

A spin balance will account for a heavy spot in the tire/wheel, but tires also have stiff spots, either due to overlapping materials in the internal belts or other manufacturing variations. Road force balancing measures these stiff spots and accounts for these as well. All OEM tires are road force balanced, but it is difficult to find a local shop that has the right equipment. SOME dealerships have it, but not all. Where I live, I am only aware of one tire shop that can do it. It is more expensive, but it can fix problems that normal balancers can't.

Even worse, I've had tire shops tell me that they can do it, when they actually can't, because the guy at the front desk doesn't know what I'm talking about. Ask specifically if they do road force balancing, and what type of equipment they use. The vast majority of good shops use the Hunter GSP9000 series, and the guy at the counter will know if he has one.

 

Worn tie rod ends can also contribute to intermittent wheel shake. I had this problem on the car I owned previous to my Mini. The steering wheel would shake at random times, not really linked with hitting a bump or a specific speed. Problem went away once tie rod ends were replaced.