Z4M roadster - rear suspension damage

S

stufarri

Member
 Standish, Lancs
Hi - I'm looking for advice and views on this please.

My 2009 Z4MR was in for it's first MOT and I chose a BMW dealer just in case it failed as the warranty was due to expire.

Embarrassingly, it did fail and both rear springs were replaced at just 21K miles under warranty.

My car was serviced 2 weeks ago at a highly recommended local-ish BMW independent and they sub-contracted a tyre place to fit 2 new rear tyres.

I picked the car up and all was well on the 25 mile journey home.

I used the car for the first time this weekend and it handles like a pig, with twitchy and wandering handling on the motorway and what appears to be slight negative camber on one side (hence the handling, I presume).

I asked for the old tyres back in case of an emergency and last night was horrified to see the inner edge of the rear tyre on the side where there is a camber issue is totally bald in a width of 2" or so.

I'm cheesed off this was not spotted on the Insp 1, 2 weeks ago and was looking for advice and in addition suspected cause and cost.

I feel it is likely to be a bent arm or possibly the spring has broken again, which seems unlikely. Any ideas how much the arms are please?

The car has only done 6K miles since the MOT with no advisories regarding the rear tyre.

Thanks in advance.
 
6k miles is enough to wear the inside edges on the rear tyres, so you can't blame the MOT - especially as the Z4M has a fair bit of negative camber.

Although BMW are getting 'sloppy' on what inspection parts of the inspection they actually check. Did you get a report on tyre & brake wear?
 
It seems quite normal for the rears to wear more on the inside edge, when I took mine off recently I too was shocked at how bald they were.

If the handling is off, my first stop would be to someone with a hunter tracking system, especially if someone has been changing suspension parts.
 
If there was a problem and it was at legal limit they would have tried to get £200 out of you for a new tyre. Any penny they can so it would have been an advisory.
 
You will get the inner tyre wear on the rear due to the combination of negative camber and toe-in, because the inside of the tyre is loaded most and the toe-in scrubs the tyre when the car is travelling straight ahead. As your starting point you need to get your car properly aligned.
 
Thanks for the reply gents.

I'd guess if I can see the negative camber (clearly more than a few degrees), the arm is likely to be bent or is there any other cause?

I'll get it taken apart and have a look as it is evident that all is not well.
 
stufarri said:
I'd guess if I can see the negative camber (clearly more than a few degrees), the arm is likely to be bent or is there any other cause?
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Both camber and toe are adjustable on the rear of your car, so if an alignment check shows that the present setting is incorrect, it may be possible to put this right by making the appropriate adjustment(s). Without knowing the history of the car, it's impossible to know if the wheel has hit a kerb or deep pothole which might have bent any of the suspension parts, or any other reason why the wheel is misaligned. Fingers crossed it's just a simple adjustment required.
 
Thanks - pothole perhaps, kerbing no (only I drive it, the Mrs doesn't like the length of the bonnet) although I am known for being a pothole dodger having always had cars with stiff suspension but I will have hit a few, no doubt.

No wheel or tyre damage as a result though but the arm may have taken the brunt of the impact.

Fingers crossed I can get it fixed soon!
 
Mick at sports & classic is a master at geo set ups mainly a Porsche guy but will do set ups on most cars sate of the art equipment and is a track day specialist so what ever yourneeds be fast road / track/ normal he's based near knutsford tel no 01565621311 mention my name he will look after you
Cheers Ian
 
Thanks for this Ian.

I'll have look myself at the weekend before getting it looked at a a local garage then take it from there.

I can't help thinking that the BMW dealer who fitted the springs has something to do with this. As you can probably tell, I have no faith in them whatoever - I'm likely to find the wrong spring fitted or some other error, I'm sure.

When you call to the Dealer Service dept to discuss negative camber issues and it is met with the response 'n e g a t i v e c a m b e r, oh..................' there is no hope really!
 
stufarri said:
I can't help thinking that the BMW dealer who fitted the springs has something to do with this. As you can probably tell, I have no faith in them whatoever - I'm likely to find the wrong spring fitted or some other error, I'm sure.
Click to expand...

I think that you could well be right on this. To fit the new spring, the rear suspension arm needs to be dropped by undoing one of the bolts on the wheel hub although there is a second bolt on the hub, which is eccentric and this adjusts the camber/toe. It is possible that the second bolt was used to drop the arm and the bolt then refitted in the wrong position.
 
Still not had chance to get the car in the garage yet but have called the BMW dealer who advised that the job sheet for my car and the BMW guidelines for replacing 2 springs does not mention a wheel alignment check. Apparently time allowed is 35 minutes to do both sides too.

I'll dust of the trolley jack at the weekend and see what I can find.
 
exdos said:
stufarri said:
I can't help thinking that the BMW dealer who fitted the springs has something to do with this. As you can probably tell, I have no faith in them whatoever - I'm likely to find the wrong spring fitted or some other error, I'm sure.
Click to expand...

I think that you could well be right on this. To fit the new spring, the rear suspension arm needs to be dropped by undoing one of the bolts on the wheel hub although there is a second bolt on the hub, which is eccentric and this adjusts the camber/toe. It is possible that the second bolt was used to drop the arm and the bolt then refitted in the wrong position.
Click to expand...


The rear springs can be fitted without removing or adjusting any suspension arms..

The bottom shocker bolt just needs removing and there is enough space to pull out the spring..

If an arm is bent,i would guess its been jacked up under one side using the suspension arm.... It would be a daft thing to do,but i have seen worse!
 
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