Wheel Bearing??

[Jepor]

Hi All 

A weird humming noise has started in my a6 , now it's not very loud but just looking for ideas , it seems to be there when I accelerate and when coasting , it's the same level all the time once started , im wondering wheel bearing,  it doesn't seem to change in pitch when turning left or right . I recently had a new outer cv joint fitted and this humming noise has started within 2 weeks . 

I am uploading a short video , you can hear it as I coast to a stop . Just wondering do ye think wheel bearing , tire noise  or something else ??   

Ive read about transmission noise can be humming , but don't think it's that as car is driving perfect and absolutely no issue with gear changes or slipping . 

 

 

 

Thanks  

 

 

[spartacus 68]

Can’t hear the video, but to be honest between road noice and background noise, these sort of videos rarely identify culprit.

If you had new outer CV joint, that may have contributed, especially if drive shaft boot was torn and and CV joint was open to the elements and contaminated.

if you’ve got a worn wheel bearing then you’ll hear constant reverberating sound, around about 40-50mph. You might be able to pinpoint if you jack up car, and hold the coil spring and get someone to rotate the wheel. Any friction on the bearing will transfer to the spring which you should feel.

Straight forward if your spanner handy, although I hate generation 2 bearings which are the press in hub variety on VW Polos for example. If generation 3 wheel bearing, then they are held in place with triple square bolts. Useful to have air hammer as the bearing is usually welded in with oxide corrosion if an alloy strut. You’ll need a breaker bar, torque wrench, etc. Fit quality F.A.G. Bearings given labour involved.

[Jepor]

Hi 

I have jacked the car up and spun the wheels and checked for play , nothing . But it is mild at the moment and might not be gone far enough to cause movement on the hub at 12 and 6 o clock   , sounds stupid but I  cant seem to spin the front wheels fast enough by hand to hear anything , back wheels no problem,  and don't have access to a full car lift .

I suppose my main worry is can the gearbox or something more serious cause this wheel bearing type humming?  it doesn't seem to change pitch when I coast as in taking my foot off the gas , so that would lead me to wheel bearing.  

Should a wheel bearing be changed at the same time as the outer cv joint , is it common for a bad cv joint to damage a wheel bearing ? 

And how long can I drive this way if its slight and no play in the wheels ?

Thanks 

[cliffcoggin]

I can't hear anything untoward, but that's not unusual. Most of the audio recordings sent to the forum supposedly have an odd noise that nobody except the owner can hear.

The usual culprit for strange humming noises like you describe is the tyres. Not because they are necessarily defective, but because the tread pattern interacts badly with some road surfaces. Have you changed the tyres recently? Have the roads on your normal routes been resurfaced recently?

[Jepor]

26 minutes ago, cliffcoggin said:

I can't hear anything untoward, but that's not unusual. Most of the audio recordings sent to the forum supposedly have an odd noise that nobody except the owner can hear.

The usual culprit for strange humming noises like you describe is the tyres. Not because they are necessarily defective, but because the tread pattern interacts badly with some road surfaces. Have you changed the tyres recently? Have the roads on your normal routes been resurfaced recently?

Hi 

I actually have got 2 new front tyres in the last month , and unfortunately they are 2 different makes in front (had a blowout and had to get a different tyre in emergency) , could be onto something as the noise is worse on smoother surfaces and not so noticeable on other surfaces . If thats only the case i can live with a slight humming. But to me if definitely sounds like a rubbing noise or bearing noise , is that possible with tyres?

[cliffcoggin]

You could test the idea if you have a spare wheel with a different brand of tyre. Change each wheel in turn to see if the noise disappears.

If you don't have a spare wheel then I guess you either have to live with the noise or spend a lot of money on new tyres that match the old ones.

Given that I can not hear the hum you mention I can not comment on it, but in my experience bearing noise is very different to tyre noise.

[Magnet]

It certainly doesn’t surprise that two different treads on the front would result in varying noises. I personally dislike different brands on the same axle, but can understand your logic in this case. 
Might be well worth swopping the odd front ones to the back and see if that alters the noise. 
What brands of tyres do you currently have on the front? 
Regards, 

Gareth. 

[spartacus 68]

On older tyres, it's possible to get flat spots, but that's not the case here. You definately want to be running with the same brand on an axle. 

[Jepor]

I'm going to leave it run for a while as there is no play in any of the wheels and if it is a bearing it will only get louder and will know for sure then, it's going for a service in 3 weeks so it would surly be worse by then if its a bearing.

And if its only an tire issue I can live with that until new tyres are called for , by the way the tyre i got was a Roadx brand and thats the only one they had in my size 255/35/ r20 at the time . Don't know what they are like for road noise . 

 

Thanks  

[Jepor]

My initial thoughts on the noise was that it had something to do with the outer cv joint that was changed as it started within 2 weeks of the job being done , but I have never heard of a bearing or humming noise from a cv joint . It was too much of a coincidence in my mind , but I suppose coincidences do happen after all   . 

 

Thanks for all yer replies gang , as always ye were very helpful.  

[Magnet]

RoadX - sounds like Chinese best, and personally I wouldn’t opt for that and another unknown brand on the front axle. 
What brands and remaining tread do you have on the back ones? 

[Jepor]

Hankook the other wheels , like I said I had a blowout and that tyre was the only one available at that time . 

Edited yesterday at 04:44 PM by Jepor

[Magnet]

Repeating :-well worth putting the pair of Hankooks on the front. 

[Gt1984]

I had my rear right wheel bearing changed last month which was quite severe almost sounded like a helicopter noise mechanic changed if I remember correctly cost about £120 problem sorted instantly 

[Jepor]

2 hours ago, Magnet said:

Repeating :-well worth putting the pair of Hankooks on the front. 

I would apart from the fact that they are getting close to end of life thread getting low  and would rather the deeper thread on the front.  

[Jepor]

I was hoping video would give an idea of what it was , you can really hear it at 31 seconds in . 

[Magnet]

If it were mine, my priority would be to sort the tyre situation out first. 
On a personal preference basis, I’ve not had the life out of Handkook tyres that make them a worthwhile consideration - others may well have different experiences.

I’m currently ‘experimenting’ with Kumho tyres on the non-Audi, in case it helps. 

[cliffcoggin]

So you have a pair of worn out tyres at the back and two unmatched new tyres at the front? It's not worth considering any thing else until you get the tyres sorted out.

[Jepor]

3 hours ago, cliffcoggin said:

So you have a pair of worn out tyres at the back and two unmatched new tyres at the front? It's not worth considering any thing else until you get the tyres sorted out.

Would the unmatched at the back not make the humming also ? 

[cliffcoggin]

No, since they presumably have been on the car for a long time so you would have noticed a noise long ago if they were responsible for it. You said, or at least implied, that the hum began recently, and the only other recent changes you have told us of are the front tyres and a CV joint. Constant velocity joints don't hum, but tyres do, so I have no doubt that one or both of the new front tyres is the cause of the noise.

Have you tried my suggestion of fitting the spare wheel as a test?

[Jepor]

Getting new tyres tomorrow and gonna move the odd ones to the back . Gonna try for a mid range to premium brand , depending on cost ! 

[cliffcoggin]

Tyres nowadays have noise ratings as well as speed, grip, energy efficiency and other ratings.

Do let us know the outcome.

[Magnet]

Not that you can do anything about it with your current wheels, but large wheels = skinny profile tyres = horrible ride quality = harsh stresses on sidewalls, which usually results in a necessity to have XL tyres, which just compounds the ill effects of above!