(Problem is fixed again, details below)
On Saturday morning, I removed my front wheels. At the beginning I thought that the tire place had over-tighten my lug nuts, but it was the other way. It was totally under-tightened. I didn't need to do any effort to loosen my wheel lug nuts.
After removing the wheels and looked at the rotors, everything looked fine.
I wiggled my brake rotors (I did not put the securing screws back when I replaced my rotors), and I saw that they had around 1/25" around 1mm free play. The rotor holes were a little bigger than the lugs, which looked ok to me.
I tried centering my brake rotor, and proceeded to install back my wheels.
One thing that I like to do, and don't know if it makes a difference, is that I put my wheels, adjust the nuts diagonally and in stages. That is tightening only a little bit and then tightening more each round until my torque wrench clicks. I torque my wheels while the tires are still up to try to center them correctly. (Even though they are supposed to be self centering)
I use 90 lbs/ft of torque on my wheels lug nuts.
I have been testing it on the highway up to 90 mph, and any wobbling/vibration is complete gone again. Very smooth and no vibration feedback at all on the steering wheel. I can go smoothly between 40 to 85 mph and all is smooth and fine.
What I can guess is that either the wheels were not originally centered and/or torque correctly (I torque my wheels as recommended and while they are still jacked up), or my rotor 1 mm or so caused the brake rotor to not be centered around the wheel assembly? Those rotors are very heavy and any non-centering issue will cause issues.
That's it, there are no more variables and now my vehicle is back running very smooth with zero vibrations. Again, I am not telling you that this will fix you vibration issue, but I can tell you that the first time (after 80+K miles of mild and severe vibrations at around 50-80 mph) after I changed my warped brake rotors, it fixed my vibration issue instantly for around 20,000 miles. Now, after I installed brand new Michelin tires and performed an alignment, it started vibrating/wobbling again and this time it was either the tire not installed/centered/torque correctly or the brake rotors were not centered correctly in the hub and causing some wobbling/vibrations.
Maybe by default some OEM brake rotors are not centered correctly in the wheel and since it has two screws locking it in place, one cannot center it correclty? Even more with warped rotors..? The dealer originally turned my OEM rotors, but that only fix it for a couple of weeks and then it was the same issue all over. Nothing to do with balancing the wheels since they were perfectly balanced (in my case).
In any case, my MDX is running very smooth with no vibrations. I know how frustrating it is to have this issue, since the MDX advanced is a very nice vehicle and it is a pity that some of them have this frustrating problem. Just sharing my experience in case you tried everything else and nothing helped...
AC
This is a very frustrating and intriguing problem. There may be many causes for some of these issues too.
I was having a very bad case of it at high speeds, and this is my experience with my MDX.
After trying everything possible, nothing really worked for 70+K miles.
So one thing I tried was to change my brake rotors for brand new ones, and suddenly all wobling/vibrations disappeared instantly. My MDX steering wheel and my entire MDX was smooth as butter at all speeds.
So I have enjoyed this smoothest drive for 20k miles or so. Suddenly I noticed that my rotors are feeling a little warped (some very hard stops) and I had to change worn front new tires for brand new Michelin Diamaris (same as what I have).
And what do you think.. THE PROBLEM is BACK..!! I know my tires are brand new and took it for a check of my balance and all checked fine.
I wonder if Discount Tires tighten my wheel nuts way too hard and warped my rotors, which is a known problem and that is why you should always torque your wheel nuts as spec'ed.
In my case, I know it is not the axles, it is not old tires, it is not balance, it is not alignment (just got one and it was still good), so I am back to finding the issue.
If I cannot fix this issue soon, I will exchange my rotors to AutoZone since they have 2 years full replacement and see if that completely solves the issue again. Before I replaced my warped rotors (dealer already had turned them but did not last), it was pretty bad and I did not had new tires, and when I changed the warped rotors, the vibration was 100% instantly and completely fixed.
I am not telling you to change your rotors to fix, since I don't know what your issue is. But, I am telling you how I originally completely fixed mine for around 20,000 miles until I got my new tires and semi-warped rotors 2 weeks ago.
It does not happen all the time, it happens when I have been driving for a while, which tends me to think that when the brake rotors are hotter, they deform further more if the nuts are not torqued correctly. I will remove my wheels, check my rotors, put back my wheels, and torque them to spec this weekend.. If that doesn't help I'll warranty exchange the rotors and test.
I'll keep you posted to see what happens, but definitely I can tell you from experience that a warped or unbalanced brake rotor can trigger strong wheel vibrations.
