25-35 MPH - Wobble/Bounce.

Keep us posted on this issue,,

I had this on my E60 and i never found the cause,although i suspected the propshaft..

Would be nice to know if there is an answer..
 
Back from Darren Woods.. Feel reassured its nothing sinister or requiring immediate action.

No issues in drive or suspension. However on the ramp at 30mph a 2mm oscillation could be seen in the NS rear. Looks like damaged bearing or hub possibly due to impact (pot hole) damage.

Car seems good otherwise.. Which has improved my mood a bit.
 
Hmmmmm...

Cant see how it would be a bearing,if the bearing was worn/damaged enough to allow the wheel to float then im sure it would give other signs.

Did the rear wheels get swapped over to negate any problems with them.
 
It's not the wheel or tyre. Watching the disc at 30mpg and it was in true. The wheel however could be seen to bounce off-axis as if the wheel isn't mounted hub centric.

The guy suggested hub or bearing damage. I may take it back there soon to have them take it apart and have a look.

Wheels weren't swapped side to side as you could clearly see it wasn't the wheel by watching the hub centre. It's very odd. Equally it did the same on the 296s I had on. I'm going for a manufacturing defect on the hub as my best guess. Roughly 2mm at the tyre edge. It's a minor 30mph only annoyance so ill have it back there when I can be bothered.

I'm just glad it was nothing more serious.
 
The disc is also bolted to the wheel bearing and hub though....

So how can they be true and the wheel is not if the hub/bearing is at fault ?
 
It has to be the mounting holes on the disc/hub. It's all i can think of. Essentially there's something wrong with the centering of the wheel on that hub.

As its done it with both sets of wheels, I doubt it's a wheel issue. Could still be I guess but then why the 313 and 296?

It really was just 1-2 mm but clearly it's enough to make the car amplify it into something I can feel between 30-35 mph. Outside those speeds either the tyre or suspension is absorbing the motion.

Interestingly while it was up in the air doing 30mph I could see the o/s doing it in a very very minor way. It made me think tyres at the time but they've been changed from the original bridgestones that did the same.

Also I noted the wear on the potenzas to be even which was very interesting considering the bridgestones wore badly on the inner.
 
Have you tried taking the wheel off and rotating it by one bolt at a time to see if theres any difference. Perhaps the hole in centre of wheel is off. Try measuring the distance between centre hole and the edge of each bolt hole. Did you have yours replaced due cracking. Perhaps you were given a second hand set?
 
The wheels I have on now (313) are new. The 296 I had on previously were also new.

Either both sets were out of round or something else is wrong. It's unlikely though possible both sets are out of round therefore I feel the mount on the hub must be at fault.
 
Maniac said:
It has to be the mounting holes on the disc/hub. It's all i can think of. Essentially there's something wrong with the centering of the wheel on that hub.

As its done it with both sets of wheels, I doubt it's a wheel issue. Could still be I guess but then why the 313 and 296?

It really was just 1-2 mm but clearly it's enough to make the car amplify it into something I can feel between 30-35 mph. Outside those speeds either the tyre or suspension is absorbing the motion.

Interestingly while it was up in the air doing 30mph I could see the o/s doing it in a very very minor way. It made me think tyres at the time but they've been changed from the original bridgestones that did the same.

Also I noted the wear on the potenzas to be even which was very interesting considering the bridgestones wore badly on the inner.
Click to expand...


But you do realise that the disc bolts to the same face that your wheel bolts too.. So both the disc and wheel would oscillilate or neither would if the hub or bearing was at fault.
 
Hi,

Had a very similar problem with my Caterham (Although a bit more noticble), tried everything and in the end out of desperation swapped drive shafts with s mate - Problem cured.
When I had my original drive shafts dynamically balanced they were less than 10 grams out!.

Stuart.
 
Z4M-2006 said:
Maniac said:
It has to be the mounting holes on the disc/hub. It's all i can think of. Essentially there's something wrong with the centering of the wheel on that hub.

As its done it with both sets of wheels, I doubt it's a wheel issue. Could still be I guess but then why the 313 and 296?

It really was just 1-2 mm but clearly it's enough to make the car amplify it into something I can feel between 30-35 mph. Outside those speeds either the tyre or suspension is absorbing the motion.

Interestingly while it was up in the air doing 30mph I could see the o/s doing it in a very very minor way. It made me think tyres at the time but they've been changed from the original bridgestones that did the same.

Also I noted the wear on the potenzas to be even which was very interesting considering the bridgestones wore badly on the inner.
Click to expand...


But you do realise that the disc bolts to the same face that your wheel bolts too.. So both the disc and wheel would oscillilate or neither would if the hub or bearing was at fault.
Click to expand...


I understand what you're saying.. But that would mean both wheels I've had on the car are out of round?
 
Yea... Seems massively unlikely doesnt it...

I dunno the answer fella,just trying to work through the symptoms to get you an answer...
 
So having thought and looked at this again, I'm going with it being very unlikely a wheel or hub issue.. and more likely that of a tyre issue. When looking at the wheel rotating, I think, where I saw a vibration, could have actually been the mirror finishing on the wheel giving me that impression. Certainly when looking at the bottom of the tyre when rotating there was a 1-2mm unevenness where it meets the road (as if the tyre was pushing out slightly at that spot). So, at this point I'm going to leave it, as either the car will be sold later in the year or if I keep it, non run flats will be going on which will likely resolve the matter. Fingers crossed.
 
I had this on Mercedes E200, at reasonable speed, you couldn't feel or sense anything, but in heavy traffic on the motorway, it felt as if both rear tyres had a stone in them at the same place.

I was doing a lot of miles at the time, and checked tires wheels, etc and finding nothing to fix - eventually sold the vehicle, because it just wasnt pleasant. I was later told by a mercedes mechanic that it was a bush that needed replacing - and it would have only been a few quid to fix.

They all do that ..... if ever there was a comment more designed to make you see red ....
 
lol yes, its not something that will make me sell the car as its only just detectable and only on the smoothest roads, which in the UK are few and far between... I just really wanted to get to the bottom of it, which, I think I have now and its nothing serious so I'll handle it dependent on whether I sell it or not later in the year.

Unless BMW are reading this, and after seeing all they've put me through want to hand over a cheap F11? Go on BMW, you know you want to! :evil:
 
Apologies Maniac, for not seeing this sooner, I would suggest the dealer may well be right this time, every part and combination of parts will have it's own natural frequency. Rotating or reciprocating parts and especially those that are connected to springs will begin to resonate at certain frequencies (resonance).

Because of manufacturing tolerances no set of assembled components will have the same natural frequency and it may well be that you have been particularly unlucky. Changing the damper settings will alter the natural frequency of the system and you should see a different effect at the same speed.

If any of the associated parts of the drivetrain were out of contricity then the vibration would always be there and not at a particular speed.
 
I can understand that SARS, thanks for the thoughts, but, as I've seen the mechanicals at speed from under the car, no components were vibrating, the brake disc was spinning inside the wheel perfectly without any vibration. Leading me to either the wheel or tyre. The wheels have been switched but the tyres are the same so it's my feeling its a tyre issue.
 
Has anybody used a dial gauge and measured the defection in each of the components etc. In this way you will be able to defiantly determine whether its hub, wheel or tyre (if its not the fist two items).

Just my 2 pence worth
 
I've not gone to those lengths as its not a major issue, just something that bugs me when I feel it from time to time. You could see visually the vertical tyre movement. Much less so with the wheel itself, but as it was mirror finish what you see doesn't exactly mean its the truth. It did occur to me to have the wheel tested with something that can measure any deflection but again it doesn't bother me enough to go to these lengths, and, if it was the wheel I'm not parting with £600 to replace it lol

I'm fairly convinced the car itself is fine as the hub was spinning smoothly. I'm not sure why the mechanic thought it was the hub when we both were staring at the disc which had no movement at all spinning at idle or 30mph wheel speed. Again I'm fairly certain its going to be tyre and I'm going non run flat if I keep the car at the end of this year when I expect the tyres will need replacing.

Its only having thought things through and seen it spinning that I'm narrowing it to the tyre now. It could have been out at manufacture but balanced in a way that its only the physical movement rather than tyre/wheel vibration making it apparent. Either that, or a pot hole I've hit thats damaged the tyre some way. Not sure, I may never know fully, but as I say I'm fairly happy its not the car mechanicals as they looked and felt, perfectly smooth. It was only the wheel and tyre I could see moving and the wheel movement could well have been a trick of the finish upon it.
 
Could well be tyres, I was driven demented by something similar with new tyres on a Merc a few years ago, the tyre shop replaced both rears as they suspected a fault with the inner carcass, and they were the same. It turned out to be a faulty batch (Avons I think).
 
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