[ClampThurst]

Hey all, I've noticed hum/drone noise coming from the drive train. It gets louder with speed and is loudest at around 60-70, particularly when off of the power(coasting when the wheels are pushing the drive train). Has anyone noticed this on theirs? Is this perhaps normal drive train noise for the F25s? All fluids, transmission, both diffs, and transfer case have been changed 10k miles ago(70k on the odometer currently).

Thanks!

[dtox9]

Potentially a rear wheel hub assembly -
I had mine replaced around 70K on my 2017 F25 last year.
It was a similar "droning" noise that you describe.

[JL16X3M-Sport]

Thanks for the posts. I will keep an eye out for this issue. My ride is only at 36K Miles.

[CrazyPilot]

my car 160K km and dont noise

[ClampThurst]

Originally Posted by dtox9

Potentially a rear wheel hub assembly -
I had mine replaced around 70K on my 2017 F25 last year.
It was a similar "droning" noise that you describe.

Did your issue come on all of the sudden or over time? Mine has been the same for about 15k miles. I would expect a bearing that is failing to get worse quickly. This has stated the same for a while.

[dtox9]

Not sure how long it was there - we heard it on the test drive, and had the repair done as part of the purchasing agreement.
Of course the dealership claimed to have never heard it before our bringing it to their attention.

[bg212]

funny enough, I was going to search the forum first an then post exactly the same question. The noise is coming from the front end as far as I can tell. Front differential oil replaced 300 miles ago, so it's out of question.

I am not sure what to blame. May be tires: I got rid of run flats and since then I started to notice the noise. Now it's louder. But it changes with the road surface. Most pronounced at 70-80 mph. _Much_ better at 60. Does not depend on RPM (seems)

My next culprits are wheel hub bearings: replacing those on my old e30 325is back in the days made all the difference in the world. I keep this in mind but I can't believe they can go bad on f25 at just 105k freeway miles.

On top of that, when I had bearings issue it on e30, the sound was more metallic, like flatter, while now it is kind of thicker. And on e30 rotating the wheels by hands would produce the noise.

[ClampThurst]

Originally Posted by bg212

funny enough, I was going to search the forum first an then post exactly the same question. The noise is coming from the front end as far as I can tell. Front differential oil replaced 300 miles ago, so it's out of question.

I am not sure what to blame. May be tires: I got rid of run flats and since then I started to notice the noise. Now it's louder. But it changes with the road surface. Most pronounced at 70-80 mph. _Much_ better at 60. Does not depend on RPM (seems)

My next culprits are wheel hub bearings: replacing those on my old e30 325is back in the days made all the difference in the world. I keep this in mind but I can't believe they can go bad on f25 at just 105k freeway miles.

On top of that, when I had bearings issue it on e30, the sound was more metallic, like flatter, while now it is kind of thicker. And on e30 rotating the wheels by hands would produce the noise.

Im not sure where mine is coming from. My thought was to put the car on the lift, remove tires, put her in drive and just listen to the various culprit under stethoscope (as I've heard they do at the dealer) but the major problem with this is that the Xtrive would have to be locked on and traction control off to prevent the traction control from freaking out due to the inconsistent tires speeds(Ive done this before and the DSC freaked out and threw every computer code in the book). So I'm not really sure how to proceed as I don't just want to start replacing parts that aren't broken.

[bg212]

ok, I am fairly confident it's wheel bearings. I took a stab and just ordered F.A.G wheel hub assemblies from rockauto $121 apiece. Based on fcpeuro video, it's a simple job, roughly brake pads and rotors replacement complexity, 1hr (2hrs top). I'll spend more time tying to diagnose it, and time is money.

Worth noting, that Timken and F.A.G. are the same company; Timken on the picture is the same F.A.G. part except an additional 'BMW' marking, that must be the reason it goes for $65 more and without bolts.

Will replace next week's weekend and report afterwards.

[ClampThurst]

Originally Posted by bg212

ok, I am fairly confident it's wheel bearings. I took a stab and just ordered F.A.G wheel hub assemblies from rockauto $121 apiece. Based on fcpeuro video, it's a simple job, roughly brake pads and rotors replacement complexity, 1hr (2hrs top). I'll spend more time tying to diagnose it, and time is money.

Worth noting, that Timken and F.A.G. are the same company; Timken on the picture is the same F.A.G. part except an additional 'BMW' marking, that must be the reason it goes for $65 more and without bolts.

Will replace next week's weekend and report afterwards.

Definitely let us know and post some pictures if you can. Thanks bud and good luck!

[richardodn]

Originally Posted by bg212

Worth noting, that Timken and F.A.G. are the same company; Timken on the picture is the same F.A.G. part except an additional 'BMW' marking, that must be the reason it goes for $65 more and without bolts.

Timken and F A G are not the same company. Timken is a bearing manufacturer that has been around for longer than most of our grandfathers. F A G is a division of Schaeffler. (So is INA.) However it wouldn't surprise me one bit that they are reselling Timken parts or Timken is a component supplier.

[bg212]

Originally Posted by richardodn

Timken and F A G are not the same company. Timken is a bearing manufacturer that has been around for longer than most of our grandfathers. F A G is a division of Schaeffler. (So is INA.) However it wouldn't surprise me one bit that they are reselling Timken parts or Timken is a component supplier.

ok, I did not mean the same company in a legal sense, but Timken and F.A.G. "wheel hub and bearing" is the same company's part, F.A.G. in this case.

[ClampThurst]

Well, I tried to diagnose the problem by putting the car on the lift and spinning all four Wheels at speed. I turned traction control completely off and as previously noted, the traction control went crazy, using differential braking and throwing out warnings. The idea was to accelerate to bout 50MPG and try and listen which wheel was the loudest. Needless to say, I was unable to complete a diagnosis. Does anyone know what the procedure would be to get all 4 wheel to spin uninterrupted but the traction control system for the purposes of diagnostic? Im sure BMW has a procedure for this somewhere.

[bg212]

did you just pressed DSC button or completely disengaged DSC (press and hold for 10 seconds)?

I did the transmission oil change recently and you had to disable (10 seconds) DCS and maintain 2k rpm for 30 seconds, but I would not say the car was happy doing that either. The wheel were spinning (they would not with DSC or DSC off), but that was not smooth. Can't say more as I was in the driver's seat.

[ClampThurst]

Originally Posted by bg212

did you just pressed DSC button or completely disengaged DSC (press and hold for 10 seconds)?

I did the transmission oil change recently and you had to disable (10 seconds) DCS and maintain 2k rpm for 30 seconds, but I would not say the car was happy doing that either. The wheel were spinning (they would not with DSC or DSC off), but that was not smooth. Can't say more as I was in the driver's seat.

Yes, I did turn it completely off. Im thinking the xdrive was the culprit as it modulates on and off normally while driving and with the car being suspended it freaked out. Im sure there is a way to get this done, pulling fuses, etc. Im sure it buried somewhere in the BMW maintenance manuals.

[Xav06]

Originally Posted by ClampThurst

Yes, I did turn it completely off. Im thinking the xdrive was the culprit as it modulates on and off normally while driving and with the car being suspended it freaked out. Im sure there is a way to get this done, pulling fuses, etc. Im sure it buried somewhere in the BMW maintenance manuals.

Just unplug an ABS sensor.

[ClampThurst]

Originally Posted by Xav06

Just unplug an ABS sensor.

one or all. Im trying to get the wheels to spin without any interruptions.

[bg212]

ok, I replaced the bearings; needless to say the noise is gone, at any speed.
See before and after videos.

The thing to note is that you cannot completely pivot the axle away; it just sits there and you need to maneuver around it un-/tightening the bolts, possibly turning wheels left/right to gain more room. No room for angle torque gauge either; i just marked ~90 deg with a sharpie.





Before:

After:

[ClampThurst]

Originally Posted by bg212

ok, I replaced the bearings; needless to say the noise is gone, at any speed.
See before and after videos.

The thing to note is that you cannot completely pivot the axle away; it just sits there and you need to maneuver around it un-/tightening the bolts, possibly turning wheels left/right to gain more room. No room for angle torque gauge either; i just marked ~90 deg with a sharpie.

Attachment 2758759

Attachment 2758760

Before:

After:

How did you know which wheel the noise was coming from? I find it almost impossible to tell on mine as its heard from everywhere in the cabin.

[heticor]

when you are driving turn left if the noise increases the bad bearing is on the right side, due the same for the right. to know if the bad bearing is on the front or back, lease careful where you hear more the noise. some time open the window help.

[bg212]

Originally Posted by ClampThurst

How did you know which wheel the noise was coming from? I find it almost impossible to tell on mine as its heard from everywhere in the cabin.

I replaced both bearings (I think it's a good idea to replace in pairs anyway).
Both were noisy; it was really loud in the driver's seat, but much quieter in the back seat.

If you watched my video "before", then you just jack up the front end and turn the wheel by hand - that's how you can tell if you have one bearing problem or both. I don't think brake pads add to that noise.

[ClampThurst]

Originally Posted by bg212

I replaced both bearings (I think it's a good idea to replace in pairs anyway).
Both were noisy; it was really loud in the driver's seat, but much quieter in the back seat.

If you watched my video "before", then you just jack up the front end and turn the wheel by hand - that's how you can tell if you have one bearing problem or both. I don't think brake pads add to that noise.

I replaced both rear bearings today and the noise is gone. Do you recall what the torque spec was on the four bolts that hold the entire hub assembly to the knuckle??? I read 80NM plus 90 degrees. I tried that but could not spin the bolts any more than about 10 degrees. I settled for 110 NM and called it quits-hope it holds