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I'd get an engineers report before too many people have fiddled with the wheel. There must be quite a few who are qualified on structural failure of aluminium components. Not cheap, but should get the money back with a claim.
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Martin, I know its not an engineer's report but the guys in Kwik Fit had never seen anything like it, to the extent that the manager called all the staff over to see it including some reps that were in at the same time!
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I have got a picture on my phone that my brother sent me but don't have a website or anything to post it to? Unless I email it to someone who has access to the photos website for here?
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Well, before I see the piccies, here's what I might expect to see.
If it's a typical fatigue failure, the spokes will have fractured - probably near a change in section towards the outer radius of the spokes. If this is the case, finding the initiation site is the important thing to do. At this point, the cause should become clear - is there a fault or defect in the material at this point, or some clumsy machining whaich has left a notch?
Is there any part of the fracture near the dent in the rim?
Number_Cruncher
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Why is the UK motorist so much in love with alloy wheels? It's hard to imagine a less suitable material for something which is safety critical and liable to be crunched and kerbed. Unlike steel, once bent, the material is seriously weakened when any attempt is made to straighten it without special measures being taken. A steel rim with a minor bend in it can safely be straightened with a hammer.
When I bought my Passat clone, I had the alloy wheels replaced with new steel wheels before sale.
659.
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Why is the UK motorist so much in love with alloy wheels?
Good question! It's beyond me too!
Aluminium suspension components are another specification which I'm not entirely comfortable with. It's the lack of a well defined endurance limit that makes me worry.
Number_Cruncher
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"Why is the UK motorist so much in love with alloy wheels?"
I would never buy a car with them........
( but then I don`t like aircon, central locking and electric windows either :)
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Aren't aeroplanes generally made from aluminium alloys?
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yes and they dont like knocks either
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TourVanMan TM < Ex RF >
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Yes, that's true - but aeroplanes are also periodically inspected by people trained in the detection of cracks. These cracks are then assessed and managed appropriately. Not a service you could obtain from your local fast fit place!
Number_Cruncher
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Yes, that's true - but aeroplanes are also periodically inspected by people trained in the detection of cracks. These cracks are then assessed and managed appropriately. Not a service you could obtain from your local fast fit place! Number_Cruncher
But it is a service that can be obtained from an NDT (Non-Destructive Testing) company, providing you are willing to remove the tyre first. An aluminium wheel can be tested by applying a Liquid dye penetrant (usually red) to it, leaving it to penetrate any defects (usually about 20 mins) then, after removing the excess surface dye, a developer (white) is applied and the dye penetrant that is in the defects gets drawn out and shows up on the suface the limitation of this method is that the paint must be removed from the wheel first and blasting the paint off can cover defects up by peening the surface over the defect.. Another method is radiography where the wheel is exposed to X or Gamma ray radiation and a photographic film is placed behind it and a negative image is produced, much like the x-ray you have at a hospital, the image is then interpreted by qualified personnel. The cost effectiveness of these services depends what the wheel is worth, I'd guess the Penetrant test may be about £50 and radiaography about £100.
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Kith,
Yes, there are myriad NDT methods available, and many companies selling them - but, this isn't a task that's ever going to become a routine part of vehicle servicing as it has done with aircraft maintenance. The value of an ordinary car is unlikely to be high enough to justify its use.
In typical automotive development practice, the presence of a crack means that the part/assembly/vehicle has failed the development test, and it is a case of going back to the drawing board. For higher value structures, like aircraft, trains, ships, submarines, oil rigs, oil pipelines, nuclear steam raising plant, cracks are expected, and management procedures of which NDT forms a part, are put in place. Cars just aren't worth this expense. Considering how many threads we have on this site where garages fail to perform basic tasks properly, I would really struggle with the concept of them doing safety critical NDT!
Going back, and responding to the question of the use of alloy for these safety critical parts, I also prefer the predominantly ductile (plastic yielding) failure mode that characterises most steel components after an overload, as opposed to the sudden, brittle fracture we see in this case.
Number_Cruncher
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Because unlike steel wheels they can be made in attractive shapes and designs.
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TourVanMan TM < Ex RF >
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Unless you are a British Leyland direct descendant, there's not a lot you can do about the shape of a wheel.
Motorists might like the design of an alloy wheel, but in the real world (look round a car park), alloy wheels are scuffed and covered in brake dust. On my car, I just pull off the plastic bit - which also serves as an audible warning device for impending kerb contact and can be replaced cheaply and dunk it in a round container of soapy water I have for cleaning it - 1 minute job. The "real" bit underneath requires no attention.
NC, I too worry a lot about aluminium suspension components as my car has these in absurdly designed profusion. I suppose if you bend these, you have other things to worry about....
659.
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Well I have to say I dont see rivers of blood on our roads from all those fatal accidents caused by failed alloy suspension components or disintegrating alloy wheels.,
Funny thing is that most things that break are steel coil springs.
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TourVanMan TM < Ex RF >
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Maybe the MOT system in the UK ensures that dangerous alloy wheels are replaced. I know which type of wheel is likely to have the higher cost of ownership.
659.
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TVM, can you put photos onto the groups.msn.com/honestjohn website if I could email you via the mods (if I can get the photo onto the computer)
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yup no problem BobbyG - dave knows my address by heart i think.....
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TourVanMan TM < Ex RF >
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TVM, have emailed the mods and Dave so hopefully you will have mail soon......ish !
Thanks again,
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>>Funny thing is that most things that break are steel coil springs.
In most cases, the failin coil springs don't cause any catastrophe. Those Citroens so affected which do cause danger are retro-fitted with a catcher device to prevent the broken coil cutting the tyre.
With good design, corrosion prevention and quality control, a steel part can be designed to give infinite life - this isn't possible for aluminium alloys. Most loaded, periodically moving engines parts must operate in this so-called infinite life regime, which typically extends beyond 10^7 cycles.
Typically, alloy components which must endure many cycles of fluctuating loads must be designed for extremely low stress - this is part of the explanation why an alloy wheel is so much thicker than a steel wheel - much thicker than a simple ratio of Young's modulus or yield stress (or 0.2% proof stress) would suggest.
Number_Cruncher
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Why is the UK motorist so much in love with alloy wheels?
Becuase they look fantastic in the right style on the right car. For some, a car is not simply a means of transport.
When I bought my Passat clone, I had the alloy wheels replaced with new steel wheels before sale.
Why do you call your car a 'Passat clone'? I'm assuming it's a Skoda Superb, are you ashamed of the badge or something?
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I refer to my Skoda Superb as a "Passat clone" because it's a fully accurate description of the product which will convey details of its mechanical makeup most easily to a wide audience.
I don't give a toss about the badge - any more than I do about the appearance of wheels, but safety and mechanical integrity are of the greatest importance to me.
659.
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Number cruncher, the wheel has split in two, not at the spokes, but literally in the middle of the wheel. It looks like someone has stood the wheel up in its natural position, and cut right through the middle givimg two 2 "wheels", one with the spokes etc, and the other with just a full circumference of alloy wheel.!
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but the guys in Kwik Fit had never seen anything like it, to the extent that the manager called all the staff over to see it including some reps that were in at the same time ....
>>
compare with " ....The wheel had split completely in two, a few inches from the inner rim. I had never seen anything like it. Nor had a couple of expert friends I spoke to the following day: a garage owner had never heard of such a thing, while an advanced driving instructor and part-time fireman - who has been a to a great many road traffic accidents in his time - told me that the only time he had known of wheels splitting like this was when the rest of the car had been reduced to scrap. ....
full story at
Alloy Wheels: A Cautionary Tale by David Finlay (15 Mar 05)
www.carkeys.co.uk/features/everything_else/5787.asp
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Vauxhall do pressed-steel wheels that look like alloys and are silver, but if you have seen them, you probably assumed they were alloys.
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Bobby, that's weird.
I was basing what I would expect to see from some work of an ex-colleague. He put together an FE model of a new wheel design for a vehicle manufacturer, and was considering fatigue loadings - the obvious weak point was the end of the spokes.
Can't wait to see the piccies!
Number_Cruncher
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Can't wait to see the piccies!
Only the one, and has now been loaded onto the MSN site.
tinyurl.com/23u9dr
{Link has since been edited, as I have now loaded this pic to an album - DD}
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Thanks Bobby & Dave for posting the piccie.
That's a frightening failure.
Was the dent in the rim on the inner rim, or the outer rim?
If you feel that expert advice were required, the best people to get to look at this would be someone from the materials & metallurgy department of a university - they will be able to determine if the problem is one of poor material, or, the reult of an overload by examining the fracture surface under a microscope (if the surfaces haven't been damaged after the fracture). I would be interested in the 2 points where the fracture crosses the change in section of the wheel well - is there any relationship between these points and the dent in the rim?
Number_Cruncher
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Looks a very thin section for a wheel made of alloy.
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Near the point of initiation (maybe) there is a balancing weight, or something resembling. How is this attached?
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The pictures certainly show that the rim has suffered a failure but they're not detailed enough to give many clue as to what caused the rim to split.
It would be really useful to see some close ups of the probable initiation points.
--
I read often, only post occasionally
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Gad - Big time problem that, even if you did dent the wheel they shouldn't fail like that. The press beckons unless BMW resolve.
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Definately needs a metalurgy specialist on this one
if you can get through to vosa (tel 0870 6060440 ) i would suggest they need telling as the wheel should no way break in half like that.
Nice to see that kwik fit were understanding and shocked.
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Thanks for all the interest shown so far. I have contacted my brother to see if he can give me any more info or photos and I will let you know as soon as he gets back to me.
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Bobby has sent me some more photos, and they can be found here:-
groups.msn.com/honestjohn/bmw.msnw
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Bobby keep us posted on this, I cannot imagine how this happened.............
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I have now managed to get the full story from my brother and although I had picked up some bits of the story wrong (it was him who was driving not her, it was a front wheel and it was RAC he called to change wheel), the main facts and issues are correct!
I have listed below his summary of events.
Whilst driving my partner's Bmw 530 in a retail park at about 20mph, i felt the steering go as if i had a puncture. There was no warning on the onboard data display. After a quick glance at the flat tyre (nearside front) i turned into the nearby service station about 50 yards away and stopped at the airline only to realise the wheel was fractured. I called the RAC and their guy was astounded when he saw it claiming that you would have to drive over a cliff to cause that damage. After putting on the spacesaver wheel he suggested I went straight to bmw with the wheel as it was.
At the dealers bodyshop they took the wheel and returned it an hour and a half later having cleaned and photographed it themselves. They pointed out a small dent on outside rim which they claim was some kind of impact damage (kerb Speed bump or Pot Hole) and this coupled with the run flat tyres had put pressure on the weakest part of the wheel causing it to crack. After phoning their customer services we were told that was their position. The wheel was not faulty.
We had a spare wheel at home which we then took to Kwik fit and the manager confirmed that it was a faulty wheel. He was incredulous as were all the staff who viewed it. He had seen all sorts of dented and buckled
wheels and suggested that had it been him he would refuse to drive the car until it was checked by an independent alloy expert. When they took the tyre off the wheel separated in two. Only the tyre kept it together. . .
Good old Dunlop 245's. The tyre was perfectly fine. it wasn't punctured and it transferred onto the spare wheel and balanced perfectly.
At present having taken advice from two others in the motor trade we are taking this to the very top of Bmw. If their official line is that damage caused to a 245 alloy by a previous wheel dent will on runflat tyres cause the wheel to split and this is normal then i'm sure they won't mind being quoted on that in the national press. I'm glad it happened at 20mph in a retail park and not at greater speeds on a motorway. The consequences don't bear thinking about.
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Dont forget to involve vosa BobbyG ,that IS what they are there for.
mine.
yours.
everybodies safety.
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Denovos wouldn't have done that would they eh ??
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Did someone deflated the tyre and the driver didn't noticed and continued to drive on the flat tyre? Any how, the wheel looks very thin and flimsy.
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If what is said is true (no reason to think otherwise of course) BMW are behaving very badly, wheels should tolerate small dents without splitting like this, what if it had gone at speed, I am not a happy bunny about this.
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bell boy, how do we involve VOSA? Have looked at their website but don't see any links to report a vehicle fault?
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For Further Information Contact: Vehicle Safety Branch, Vehicle and Operator Services Agency, Berkeley House, Croydon Street, Bristol, BS5 ODA. Tel: 0117-9543300
ring them 8.00am in the morning
see what they have to say
hopefully they will advise
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Cheers, will pass that on.
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One more photo (courtesy of Bobby) loaded which shows the dent that the garage say is the cause of the problem!
groups.msn.com/honestjohn/bmw.msnw?action=ShowPhot...8
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Thanks for loading that Dave, I promise thats the last!
As you say, and have expertly highlighted on the photo, the dent at the bottom of the pic, which is the inside of the rim, is the dent that the garage is saying is the root of the problem.
As you can see from the collective photos, there is no direct link in the form of split etc between the dent on the rim and the actual split in the wheel.
Does anyone by chance have any experience of dealing with BMW UK? Have any names or email addresses of anyone other than Customer Services?
Anyone know of any forums for 5 owners whereby we could check to see if there is any previous history of this?
Once again. many thanks for all the input so far. On a personal basis, I am astounded that BMW are not willing to just swap the wheel and be over and done with which, at the time, would have kept her happy.
Instead she is now on a mission.......
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If those are the 124 Alloys I've read reports of these failing like this with only light dings. IIRC BMW stuck to their guns and wouldn't budge on accident damage. If you search through E60net or BMW World you'll find a few threads
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I haven't got a chance to look at BMW World yet but E60net threw up these which at first glance look like similar failures.
forums.e60.net/index.php?showtopic=6523&hl=cracked...y
forums.e60.net/index.php?showtopic=36975&hl=cracke...y
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Martin, thanks for that, found this one thread which looks very similar, not sure if the wheel is exactly the same?
(The pic is near bottom of page, you don't need to register to view it).
forums.e60.net/index.php?showtopic=6523&hl=split+a...y
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No worries. At first glance looks the same 7 spokes.
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This looks like a recall on safety grounds issue to me. I can see a mechanism whereby an impact on the unsupported side of the wheel (wide, and spoked at one end) would cause the maximum stress, near the spokes.
If one assumes the design criteria of an alloy wheel is only to be strong where it needs to be (like bridges) I'd have though the area that failed, ought to be thicker/stronger than the rest of the tyre well.
Are the 'run flat' tyres part of the BMW specification? I could see an excuse being used here if they were not, but if they are, then I doubt the excuse is very valid.
I would love to read a report into this written by a properly qualified metallurgist and structural engineer.
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From the final picture posted by Bobby, the dent in the rim is equidistant (in terms of angle) from the two points where the crack suddenly changes direction, this supports the garage's assertion that the dent is the cause of the failure.
I think that if a runflat type of tyre weren't fitted, an ordinary tyre would probably have failed during the impact.
There is little sign of any significant plastic deformation prior to failure - which can be seen by looking at the pictures which show the two halves of the wheel close together.
I now think the only useful question to ask a metallurgist would be to determine if the material of the wheel meets its specifications (even this is only meaningful if you can obtain BMW's original requirements specification for the wheel - unlikely!)
My humble view from a distance* is that the local rim damage caused by the impact was sufficient to scrap the wheel anyway, and because of that there's no point in pushing this matter. Sorry.
The impact must have been sufficiently hard to be felt, and the dent in the rim must have caused some ride vibrations - i.e. the fault must have been obvious even before the wheel split in two.
My only remaining questions are how long in time, and how many miles were there between the impact event and the wheel failure?
Number_Cruncher
* Of course, I've only seen the piccies - it's entirely possible that I've missed the vital "clue" and I'm completely wrong!
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with due respect Number_Cruncher the rim has a dent and you say a catrasphoric cracking of the wheel is acceptable and indeed going to happen because of the dent
dont agree at all
at all
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I didn't say that bell boy.
Number_Cruncher
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From the final picture posted by Bobby, the dent in the rim is equidistant (in terms of angle) from the two points where the crack suddenly changes direction, this supports the garage's assertion that the dent is the cause of the failure. I think that if a runflat type of tyre weren't fitted, an ordinary tyre would probably have failed during the impact.
I'll second that on both points. The "step" in the annular crack is probably significant and if this had been a normal tubeless tyre, then it may well have noticably deflated from leakage through the initial cracking prior to the final catastrophic collapse of the rim.
The brittle fracture of the well does raise a question as to the specification, or quality control, of the alloy used.
The other question is; did the dent precede the tyre deflation, or was a flat tyre the reason the rim hit a speed hump or similar?
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>>The other question is; did the dent precede the tyre deflation, or was a flat tyre the reason the rim hit a speed hump or similar?
That's a good question - I keep forgetting that this is a run-flat tyre, and if a flat tyre hit a bump, it would cause much more damage than a normally inflated tyre.
Number_Cruncher
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even so, whether the wheel is punctured or not, there seems to be no safety margin. I had an e39 with a wheel that was significantly more dented/warped than this one, albeit on a 33 Turbine Style and without run flat tyres and I had no problems other than an annoying vibration. I drove 500 odd miles with it before changing it as the vibrations only came about at 55-65mph and there was absolutely no degradation of the wheel.
Personally I would push BMW on this. Whether the alloy needed replacing or not is immaterial when the exposure to danger is taken into account
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Is he still driving the car? I wouldn't be unless on different wheels!
Also prejudices any claim that it is dangerous if it is still in use.
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I have to say, thats a significant dent, it s not just the rim thats dented, its been "flatted" further in as well. I reckon that why the fracture occured because the rim could not deform and absorb all the energy.
Its hit something rather large. The use of run flats has as much to do with this as the wheel metalurgy.
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TourVanMan TM < Ex RF >
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I have to say, thats a significant dent, it s not just the rim thats dented, its been "flatted" further in as well.
That's what it looks like to me as well. In the vertical plane where the tyre seats (and further in as well) the wheel is no longer circular. It's more than just minor damage to the outer flange. When being driven, the distortion would cause a cyclic radial load on the wheel that the designer didn't envisage.
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L\'escargot.
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