rear tyre wear question and tyre noise

[Ryoken]

ive got a 2001 4.4 as my sig , and I'm getting what I can only describe as a noise at 35 to 40 mph , its a rotating noise , not grating , doesn't sound wheel bearing , took it to my indy and he took it out . thinks its tyres, he checked all my bearings said , "cant see anything there". unless its the start of a failing component , any whoo,
ive got hankook ventus st's on . 2 new and 2 part worn. load of meat left on these, however the outer edge on the rears a re worn quite bad, in the uk they would be an advisory on the mot id have thought . he then ran his hands on the tread of the tyres and said there is a noticeable step on the tread, not going from inner and outer but forward and back , he thinks that could cause some road noise , all 4 tyres are like this,
I'm thinking the guy that had it before me (who put on the 4 tyres) has had the rears off another x5 and had the tyres on the other rear corners so that's why the wear is showing on the outside .
ideas?

if it is tyre noise, I can cope with that ill just put the radio louder
another note is while we were under the car , noticed the rear diff, was covered in crap , looks like ive had an diff oil leak there in the past , might be that the diff is complaining , as at about 70 to 80 , I'm getting a droning from what seems the rear.
going to change tranny , frot and rear diff. in January

[14thbmw]

For the tyres, start with a good alignment and balance each one. They may be out of round given the wear, in which case balancing won't solve the problem - you'll either have to have them shaved to round or just replace them (which may be wise given the shoulder wear).

I have had Hankooks on a sports car and they were fine, but I don't recall them having a weight rating sufficient for the X5 - check on that; I could be wrong.

[Ryoken]

ive had the 4 wheel alignment, done a bit ago , thinking the wear was caused by my car.
it wasn't far out tbh . so my car wasn't causing the outer wear. i'll, take a photo of the wear when I get home later.
thing is now I know its there now the noise and its annoying me more than it did before

[14thbmw]

If the outside is wearing, that could be aggressive driving, or the prior owner might have taken the tires off and switched them so the inside (which does tend to wear faster) is on the outside. If the tires are directional (look for a rotation arrow on the sidewall), that was a mistake but you can switch the wheel/tire from side to side and they should rotate correctly.

The step you describe sounds like what we call cupping, which is caused by bad alignment - but it could be from some time ago.

The noise could be the tires or the diff, or???

[Ryoken]

its an odd sound tbh, I've tried to explain it to people, and you cant really type what it sounds like . I seems to be getting a few of late , there's the rotational sound at 30 to 40 mph, and then there's like a droning noise about 70 , the droning one does sound like its coming from the back , and the 30 mph one sound like its coming from somewhere on the right hand side
and I think your right in him swapping them around on the back as my 4 wheel tracking was ok

[jfoj]

Run your palm over the tire tread lugs in both direction.

If there is heel/toe wear on the tread lugs the tires will be noisy.

You can also have someone else drive the car and you will be able to hear noisy tires as the vehicle nears you and drives by you.

See if the tires can be rotated in some manner.

I have tires that are not directional, but they have an "outside" so I swap them from side to side every so often to even out any heel/toe wear.

The drone at 70 MPH could be exhaust if it has been modified or if for some reason the exhaust is touching the body or frame somewhere.

[Ryoken]

just a quick update for you guys. took car in to tyre place to get 4 wheel alignment done and wheel balancing , , mechanic said this wouldn't help, and decided to go for a drive in my car. said sounds like a wheel bearing ,
put car on ramps, and spun wheels and checked all 4 , weirdly , his mate spun the wheel and he held the springs and other parts of the suspension , on that corner saying if a bearing is rumbling you can feel it .new one on me that, but hey ho ,

any way, he did the same with the rear , nothing on there either, he then held the rear diff. if you hold the diff and spin the rear wheels you can feel quite clearly the gears moving inside, he said , this isn't right and this would cause noise and a rumble at motorway speed ( it does)
now I know the rear diff was horrible had a previous oil leak at some point, so I'm hoping the diff is just short of oil ,. other wise , joys of joys I needs a new one or mine refurbishing

[jfoj]

Before you concede to differential problem, I would do some more investigation. Keep this in mind, what the test did while the vehicle was in the air with one wheel being held is not what would happened on a straight roadway.

The fastest and easiest way to rule out tire problems is to swap a known good set of tires on the vehicle, if the tires are the problem, you will know in less than a few miles that the problem is with the tires.

Most bearing noises tend to only be heard easily at lower speeds.