Road noise - tyres or diff?

N

n1nja-frog

Member
Derby
Owned my Z4 since May, and initially the road noise was fine. However in the last couple of weeks i've noticed / tuned into what seems like an unacceptably loud droning / humming noise when rolling. It does depend on the road surface as older, crappy road surfaces create a stupidly loud noise whereas smoother, newer road surfaces the noise is more tolerable.

The car is on Bridgestone Potenza runflats which I believe to be 4 - 5 years old. The noise itself is a constant noise, no clunking or knocking present.

Any thoughts?

Cheers

Anthony
 
Or wheel bearings. I've just had an old 4 year budget tyre replaced for a hancook, and it's made a massive difference to the sound when driving. It wasn't a run flat but I guess the same principle can be applied.
 
Most likely the tyres or a wheel bearing. You could try swapping the wheels/tyres around and see if the noise moves around.
 
n1nja-frog said:
Well i've found what looks to be a bit of CV grease on the drivers side rear wheel. So I assume a split CV boot could cause this? As I don't think it's the tyres :(

20141027_144857 by DEAF N1NJA, on Flickr

The list could be endless then.....:(
Click to expand...

Tyres can knock out some weird noises. When I bought my Zed I stopped twice on the drive home convinced there was a collapsed wheel bearing. The noise was seriously loud but it turned out to be the tyres, swapped them and the noise was no more.

Are you sure that's not just dog piss on your wheel?
 
I swear it's too loud to be the tyres. I cringe every time I drive past a pedestrian! Putting me off even driving the car atm :(

Fairly sure it isn't as it's got the consistency of grease - though I can't find much info on here about replacement CV joints / boots.
 
Here's a thought, and I'm serious - check the tyre pressures! I had a noise over a period of a few weeks last year - I tried everything, wheelbearings being the most likely - I even took the brakes apart as I'd not so long before changed the disks. Then (maybe 300 miles later) I happened to check the tyre pressures, and amazingly discovered the rear left was totally flat. With the RFTs it was not visible. Doh!

On the positive side, it pushed me down the non-RFT route. Great move!
 
Cheers for the suggestion, first thing I checked! All now at the correct tyre pressures (36psi rear, 33psi front) but no difference. Maybe it's just typical road noise!

Swapping the tyres for non runflats next week - Michelin Pilot Sport 3s. Will see if this makes any difference.
 
A way to quickly test for a shot wheel bearing back in my mechanicing days was to listen to the droning noise, if the noise increases going round a left hand bend, it's a right side bearing as it comes under load or vice versa. If there's no change in noise levels then chances are it's something else - tyres, drive shaft bearings etc. Checkout that fluid on your rear wheel though asap - it could be something totally unrelated, like brake fluid ....or cat piss!
 
Dewi said:
A way to quickly test for a shot wheel bearing back in my mechanicing days was to listen to the droning noise, if the noise increases going round a left hand bend, it's a right side bearing as it comes under load or vice versa. If there's no change in noise levels then chances are it's something else - tyres, drive shaft bearings etc. Checkout that fluid on your rear wheel though asap - it could be something totally unrelated, like brake fluid ....or cat piss!
Click to expand...

It's a constant drone / grind. Load on either side does not change the tone / level or frequency of the noise. Road surface has a HUGE effect. On brand new smooth road it's virtually silent bar a slight hum.

Here's a video I took to demonstrate the typical volume @30mph :

https://flic.kr/p/pyQYZM

Also I cleaned the wheels, took it for a drive and can find no more fluid on them - could well have been cats piss :x :headbang:
 
I think you answered your own question when you say that road surface makes a HUGE difference = tyres

That's my thinking also
 
I was amazed at how much noise the cheap tyres fitted to my Zed actually made. It had 4 brand spanking Sunny tyres on (I guess the seller thought go cheap as it's going up for sale) but it was so bloody noisy I binned them within days. I remember my trepidation as I drove out of the tyre centre hundreds of pounds lighter wondering if the noise would still be there! Thankfully it wasn't. :)
 
It will be the tyres without doubt..

They Z is so twitchy to different rubber,and with the driver sitting so near the rear wheels the noise is easier to detect..

I had some Falkens on a 3.0coupe once,they where horrendous..
 
Been running with the standard Bridgestone RFT for 6 years and never any road noise even when the rears needed changing still no noise
 
See mine's horrific so I think it's got to be something other than the tyres as I can almost distinctly separate the tyre noise and this 'rumble' - which is still massively influenced by the road surface, but even on the smoothest, newest surface it's still there, and can come and go every half second or so. It's like a rumble / drone / grind sort of noise?

Getting me down now as I had a RenaulSport Megane R26 before this and it suffered a very similar issue, which after changing all wheel bearings, steering hubs, intermediate and layshaft bearings wasn't sorted -so sold for this :(
 
It has full BMW warranty, so thinking of chucking it into them and see if they'll help?

One thing is the rear RFTs are not far off the wear markers (so quite low)?
 
n1nja-frog said:
It has full BMW warranty, so thinking of chucking it into them and see if they'll help?

One thing is the rear RFTs are not far off the wear markers (so quite low)?
Click to expand...

You're heading for fresh rubber anyhow so why not make that your first move , then if still doing it you can eliminate tyres as a possible problem :?
 
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