wheel vibrations between 75-85 mph

[illerbiller]

2018, diesel, Msport pkg DHP, 38,000 miles
good day everyone, Im having an issue with my X5 and the dealership(s) can't figure out the problem. Been having intermittent harmonic steering wheel and chassis vibrations at highways speeds between 75-85mph. New Michelin PilotSport4S in 20'S, wheels high speed balanced and Roadforce balanced twice; tires and rims are perfect. Two shop foremans have confirmed the vibrations on test drives with me. Local dealership replaced the transfer case, thrush bushings and the front prop shaft to no avail, they Roadforced the wheels again and basically gave up. Took it back to the original dealership, one foreman suggested it might be because they are not "Star-rated' tires, but Michelin does not offer the "Star" in the 20inch PilotSport4S, also, I ran these tires before on my previous X5 with no issues, so I think they ruled that out. They changed two front wheel bearings, problem got better but the vibrations are still there. They seem to be stumped as well now. Has anyone experienced this issue before?
btw, it just ran out of warranty few days ago

[Clifton]

Are you testing after each “fix” by using the same stretch of road?

I’ve found a highway near me that has a frequency of undulations that causes a vibration between 70-80 mph. The stretch of road then connects to an interstate where the vibration goes away.

I’ve owned two F15 X5d, and vibrations always occurred when I travel on that highway.

[M302_imola]

I was going to suggest a transfer case recalibration using ISTA, but you said they replaced the TC so there goes my suggestion.

It's low mileage for front control arms to fail, but I've heard others on here have failure at low miles. Might look there next. You sound OCD like me, so I know that drives you crazy!!!

[illerbiller]

yes I test on the same part of the highway each time so I can distinguish road noise from tire. I do have ocd lol and this is driving me nuts

[Clifton]

Originally Posted by illerbiller

yes I test on the same part of the highway each time so I can distinguish road noise from tire. I do have ocd lol and this is driving me nuts

Have you considered testing for vibrations on another road(s)? It may not be your X5 that is the issue. Worth a shot.

[illerbiller]

Originally Posted by Clifton

Have you considered testing for vibrations on another road(s)? It may not be your X5 that is the issue. Worth a shot.

that was the first thing i ruled out...have over 30 min in video on different highways ..but it's the newly paved smooth roads is where the problem is prevalent

[Breakmywalletf15]

Sounds like control arms

[lht5059]

Oh man, this brings back bad memories lol...

My original control arms failed at around 43k M302_imola, so you are on the money there -- keep an eye out for this too OP. Maybe post a video or two of the sound if you have some good extract?

A few symptoms popped up on mine, and keep in mind I drive around the horrible road of DC/PA/NJ/NYC, but they all went away after I change both front bearings, both front upper AND lower control arms, road-force balanced the tires to as low/green as possible 3-4 different times IN A ROW (I had the wheels powder coated so tires went off, it was well balanced before...). In a timeline:

1. I had a rhythmic humming sound that only happens above 75mph; this doesn't change regardless of driving mode, especially during cruising in eco pro, so engine issues are more-or-less ruled out. I also swapped out my stock 19s for 611s and put the 19s on my GF's car with no issue, while my X6 on 611s persisted the same sound, so wheel+tires weren't a problem at this point. At this stage, dealers and local indies didn't think there was anything wrong... I daily like this for like a good year (discounting a year of covid where we drove the GF's 35d instead)... I was, and still am, convinced that I got a bad set of bearings; but I was moving and changing job so didn't have time to address it.

2. Eventually after a good few weeks of extra-spirited driving with a wider set of wheels, a faint ticking sound later appeared at around 40mph. This turned into a louder clicking sound that, at first, comes and goes, but then stayed consistent across all speeds every single time I drive the car. I was super busy so drove the car around with this for a week or two before it sounded like a loud rusty spring, especially after hard acceleration and/or braking; this is when I finally found time to take it in for control arms.

3. After swapping out all 4 front control arms and bearings, there was a vibration only at 80-90+ mph that would slightly shake the steering wheels and vibrates the seats + floor. This is when I took my wheel guy for a few hard drives back-to-back and he tried to balance the tires after every drive, 3-4 drives in a row; I think it was the rears that gave him a hard time at the end of the day. Afterward, I haven't had any more issues and the car drives great now...

Other than that, I can't think of any other reason why this would happen out of nowhere unless you have recently kissed some crazy pothole, added badly fitting spacers (I am also running spacers), or stressed other components out w extra torque somehow...

[cfm56d7b]

Did the dealer inspect the engine mounts?

[illerbiller]

Originally Posted by cfm56d7b

Did the dealer inspect the engine mounts?

well, the third dealership put a different set of wheels and tires on (same style and size), some old beat up Conti's and super rashed up rims, totally beat up ride but NO MORE HARMONIC VIBRATION ...Michelin standing behind their warranty and these PilotSport4S's are basically new....how could the Roadforce machine deem these to be perfect???!!...maybe i'll try putting these wheel on a buddy's X5 and see if they vibrate the same

[cfm56d7b]

Originally Posted by illerbiller

well, the third dealership put a different set of wheels and tires on (same style and size), some old beat up Conti's and super rashed up rims, totally beat up ride but NO MORE HARMONIC VIBRATION ...Michelin standing behind their warranty and these PilotSport4S's are basically new....how could the Roadforce machine deem these to be perfect???!!...maybe i'll try putting these wheel on a buddy's X5 and see if they vibrate the same

Thanks for the update. This suggests that even RoadForce machinery requires calibration.

[illerbiller]

Originally Posted by cfm56d7b

Thanks for the update. This suggests that even RoadForce machinery requires calibration.

was balanced on two different HunterRoadFoece machines, it's the fact that the vibration happens only at about 80mph and the balance machine balances up to about 65mph is why they couldnt detect it, it was the Pico machine that detected the irregularity in the tires