XSeries-forum

Hi all,
After hearing lots (and lots) of Scare Stories and Old wives Tales, I have managed to separate most into their relevant box, I just have a problem with one that I cannot get a definitive answer to!-
Tyres-
My front tyres are worn to below legal, Thanks to the previous owner not having had a 4wd Laser alignment, The problem is, the rear tyres have plenty life left in them!
Does anyone have experience of their cars transmission turning to dust as quick as the proverbial Vampire/Garlic Combo when Tyre treads differ greatly? (Not talking off road/Slicks combo).
Thanks guys n gals.

In a word NO......however I advise replacing illegal tyres asap.

I believe replacing both tyres on an axle at the same time will reduce any possibility of problems - I think the transmissin windup and diffs going bang happen when there are several different makes and tread depths on the same car - never a great idea on any car, and definitely not an X. Difference in tread depth between front and rear isn't going to cause any huge issue AFAIK if you are running the same tyres all 4 ends.

Can only speak of my experience.

On pre facelift (i.e. Non xdrive) had no issues at all and you would be less susceptible in my mind as the transfer box is just a planetary gear set and a chain.

The xdrive has clutches etc so could cause an issue.

As said try to keep side to side same as the front & rear diffs are not the greatest!!

[quote="AW8"]
In a word NO......however I advise replacing illegal tyres asap.
[/quote]

I have a mobile fitter booked for Thursday, where they're changing all four (rears have 4mm+ left), fronts are still legal but I'm uncomfortable with the outer wear. I fully recommend the 4 wheel laser align.
I'm thankful that this has been cleared up, at least next time I'm not going to be feared by only changing fronts or rears on their own.

Based on what has been reported on here, it is more risky to have a wide tread depth front/rear (brand new set on one axle, almost bald on the other) that upsets the system more frequently, or even more likely one new tyre on an otherwise worn set.

Like all these things it will depend upon driving style and road conditions.  Hooning about on the twisties puts more load than the same on a motorway!

The E53 was BMWs first attempt at AWD and they needed to learn some serious lessons when they borrowed from LandRover.  Unfortunately the customer was the testing team.  My old 20 strong Mk1 & 2 Disco fleet suffered very badly from broken diffs and transfer boxes.  Some vehicles repeatedly broke them even with different drivers. 

Many E53s have no issue with diffs and tyres whereas others do.  It's a lottery!  Changing tyres as a set seems to be the 'safest' option which doesn't 'test the metal'.

Thank you everyone, The outer tread was worn before I got it and the first thing I did was 4 Wheel laser align it, After Thursday it'll have Brand new Rubber all around too! lol

[quote="chelsea"]
if the front tyres are wearing their outer edges then i would be replacing all the linkages before having it four wheel aligned,this happened to mine on the near side and it has proved to be the linkages.
[/quote]

curious - why would you do that when 4 wheel laser alignment is a) cheaper and b) usually needs done at some point anyway?

My local tyre garage does it for free (if no alignment needed) and £30 for front adjustment and a further £30 for rear alignment

Smee

Hi changed both rears on my X6 (11 plate with 45000 mls) last year due wear. Approx 3 months later front TX box broke. BMW dealer suggested was due to differences in wear between front and rear tyres. Fitted new front TX box (extended warranty)and tyres so fingers crossed it won't happen again.

All 4 tyres are now changed for New, Fingers crossed nowt breaks now!

Had alignment done today due to some wear on inside edge on passengers side rear, it was -4?? However after adjustment the best they could get either side was -2.50. Still far to much. Looks like I need some bushes although to be honest I can't really see anything that looks dodgy. Am tempted to try and put an end to this (is that possible)and poly the rear. 

Let the air out of the rear suspension and check again.

The way these are designed means the air system always keeps the suspension under pressure and it masks all wear and play to the touch.

You may be unpleasantly surprised.........

So , Steamytrotter Am I right in saying, jack the rear up (suspension hanging) let the air out and I'll be able to find any play that might be there??

Yep that's right.

The easiest way I found was to undo the 2 pipes in the boot. (Spare wheel out)
This lets the air out of the whole system.
You can pull the compressor fuse out too, but I never bothered and it didn't cut in for me.

Then you can check all the linkages and bushes.

I had the bottom rose joint and one top arm (rear I think it was) on both sides gone.
With air in all felt fine but without air it was really quite bad.

Thanks for quick reply, unfortunately it'll have to wait till the weekend to check. Really boring stuff like earning a living gets in the way during the week. Will post up though what I find.