"humming" at certain speeds - any ideas?

[manmaths]

(the car - not me)

Hi all,

over the last week or so my car has developed a "hum" at certain speeds only. This is in addition to the expected road noise through the tyres etc.

I get a sort of humming resonance at around 47-50mph which goes away over 50, and then again at around 57-60mph.

I think I can rule out the gearbox/drivetrain because the noise is present at 48mph in 4th gear, 5th gear and even neutral. I have also ruled out loose wheel nuts.

Any ideas what could be the problem??

Nathan

[andrewrob]

Wheel bearing maybe?

[Dr Jekyll]

Drive shaft on it's way out?

[willmagrath]

I had this for the past year, pulled off the tires and they were warped (not round!). So i bought new ones and all is good

[eybic]

Does the pitch/ volume change when you turn slightly?

I'd suspect wheel bearing initially.

[mikeveal]

Have you checked that your boot is Oompah Lumpah free?

[croakey]

What car is it?

Had very similar on my a4 - was "sawtoothed" rear tyres.

[smele]

croakey said:

What car is it?

Had very similar on my a4 - was "sawtoothed" rear tyres.

Agree, had that on a BMW, same sort of speed and particularly noticeable on nice smooth new tarmac.

[Riley Blue]

smele said:

croakey said:

What car is it?

Had very similar on my a4 - was "sawtoothed" rear tyres.

Agree, had that on a BMW, same sort of speed and particularly noticeable on nice smooth new tarmac.

Seems like that to me too, it happened on my two A4s and both times was was tyres, not bearings.

[LuS1fer]

I have a Fiesta and both rear wheel bearings went and produced an annoying whine.

[xRIEx]

Teach it the words.

[johnny fotze]

Does it change in line with speed, revs, or not at all?

[DanielJames]

Wheel bearings or tyres.

[mybrainhurts]

Check the boot for wasps.

[GrizzlyBear]

manmaths said:

(the car - not me)

Hi all,

over the last week or so my car has developed a "hum" at certain speeds only. This is in addition to the expected road noise through the tyres etc.

I get a sort of humming resonance at around 47-50mph which goes away over 50, and then again at around 57-60mph.

I think I can rule out the gearbox/drivetrain because the noise is present at 48mph in 4th gear, 5th gear and even neutral. I have also ruled out loose wheel nuts.

Any ideas what could be the problem??

Nathan

Is it definitely mechanical?

Is any external trim not attached correctly?

Just thinking it might be a window seal or maybe a bit of plastic vibrating.

[Limpet]

Riley Blue said:

smele said:

croakey said:

What car is it?

Had very similar on my a4 - was "sawtoothed" rear tyres.

Agree, had that on a BMW, same sort of speed and particularly noticeable on nice smooth new tarmac.

Seems like that to me too, it happened on my two A4s and both times was was tyres, not bearings.

Had the same thing on a mk1 Focus. New tyres cured it.

[chrispmartha]

willmagrath said:

I had this for the past year, pulled off the tires and they were warped (not round!). So i bought new ones and all is good

This I reckon, I had the same thing on the banger 9-5 I bought, changed the rear tyres and its like a different car.

[manmaths]

Limpet said:

Riley Blue said:

smele said:

croakey said:

What car is it?

Had very similar on my a4 - was "sawtoothed" rear tyres.

Agree, had that on a BMW, same sort of speed and particularly noticeable on nice smooth new tarmac.

Seems like that to me too, it happened on my two A4s and both times was was tyres, not bearings.

Had the same thing on a mk1 Focus. New tyres cured it.

I'm assuming tyres become like this because of alignment issues? Tyres are only 3 months old and have covered around 4-5000 miles. Should I get the alignment checked? Can't remember last time this was done so maybe worth a shout. I had the wheels off a while ago to change brake pads and didn't notice any issues with them.
They are budget tyres though

GrizzlyBear said:

Is it definitely mechanical?

Is any external trim not attached correctly?

Just thinking it might be a window seal or maybe a bit of plastic vibrating.

Had the undertray off a while ago to change oil but checked around the car and no trim issues.

anonymous said:

[redacted]

Thanks to those who have suggested wheel bearing. I will check this out just to be sure.

mybrainhurts said:

Check the boot for wasps.

xRIEx said:

Teach it the words.

[manmaths]

Dr Jekyll said:

Drive shaft on it's way out?

mmmm. I hope not! I do have a bit of a clunk sometimes. Local garage didn't find any issues with suspension or bushings - could this be symptomatic of drive shaft issues too?

I am teaching myself to work on this car. So far have mastered discs, pads, fluids and filters - changed a fuel pump too. But still lots I don't know - hence being clueless with this issue.

The car is an 05 Mazda6 Diesel family workhorse / shed

[Hooli]

xRIEx said:

Teach it the words.