What is the root of this BMW design flaw in all 3,5,7 series BMW trunk wiring looms?

The inside handles seem to be designed to break at the 8 to 10 year mark. The have a slot molded in to the highest stress point, I might add I don't see any reason for it. Other than to help the dealer sell replacement handles. Other than the door handles I'm a happy Toyota owner, had a Camry, have a T-100 still a sharp looking truck, have a Lexus and an Avalon. My wife is a persistent patient shopper, and will wait until she finds a great used car at a steal. Mikek

ok, you're not going to like a lot of what i have to say, so i'm going to preface this by reminding you that i recognize that you may be sincere in what you believe - so don't take all this personally.

bmw's power trains are indeed "phenomenal", but for entirely different reasons than those by which others would measure.

bmw are pioneers in transmission life limitation. gm and frod used to do this by simply using cheapo clutch packs in their automatics, and cheapo steel in their sticks so they'd wear out or spall respectively. bmw didn't like these failure modes, so, not content with "sealed for life", they decided to design fatigue /into/ their cogs so they'd fatigue and break. [the beauty of fatigue is that you don't get "whiny transmission" or slippage symptoms that develop over time - one second it works, the next, it's a catastrophic failure.] i know this because one of my old profs was their outside consultant, and it was interesting to us as students because the metallurgical problem was how to ensure that individual ratios would fail when each one operates somewhere within the three [very different mechanism] fatigue "regimes". it's a "phenomenal" technical achievement and one that bmw paid a lot of money to solve. all the majors are now reputed to have followed their lead to some extent. the real kicker is that it costs bmw ~20% more in materials and q.c. to ensure this life limitation, but the mba's did their math and it pays because it causes big ticket repairs to vehicles that are depreciated thus ensuring that the vehicle gets junked.

it's not cost dude. see above.

for a company that spends hundreds of millions each and every year on research, [although that's substantially less than they spend on advertising!] do you really think all that is simply oversight?

not from where i sit they don't. single row timing chain, poor materials, both are manifestation of their overall design philosophy - they don't sell you a car, they're selling you a period of usage with a whole bunch of marking brainwash attached.

no they don't - they use macpherson strut. if they were serious, they'd use wishbone.

now, bmw are at least smart enough to have realized before most others, porsche included, that rear suspension is crucial to making a cheaply made car handle better, so they do at least concede to a little extra expenditure on that, but by definition, any front suspension that offers no camber control is just cheap junk.

it most definitely is. bmw are the pioneers of modern life limitation control. nobody has spent more on ensuring that whatever they use works for a closely defined period, and not a moment longer. as said before, it costs more to do this, but it pays. customers buying new are snowed into believing this "ultimate driving machine" advertising [the ultimate meaningless tagline!] so they don't care. and second [or later] owners have no recourse. it gets older bmw's [and their parts] off the road, and keeps sales up.

Everybody does this, though. This is how cars are designed. I believe that GM was the original innovator of the concept, at least according to my old statics professor who had been a GM engineer in the fifties. He was very enthusiastic about the whole concept of designing for specific failures.

That said, I have 480,000 miles on the transmission in my old 2002, and I had a Chrysler Laser that went through five transmissions before I gave up on the thing.

I think some of the failures, like VANOS seals and the DISA failures, are the result of trying to push the technology too hard too fast.

And some of them, like the perpetually underdesigned cooling systems, are the result of German engineers not understanding that the weather around the world is not the same as it is in Bavaria.

But some of them are the result of typical German Engineering Disease, where engineers will never use one part to do a job when they can use five.

Still, when I drive the 2002, it makes me smile. I'm willing to put up with a remarkable amount of crap for that. Not everyone is, but that's why they make so many different kinds of cars.

That is the philosophy of the entire auto industry and singling out one manufacturer for it is disingenuous.

--scott

correct. i'm referring to the technique which bmw use - as i said, the "traditional" approach was having stuff wear out, which customers hate. sudden failure is the way to keep them all hooked, and particularly with bmw, "you must be a hard driver - it's the price you pay for driving a 'sports' car" excuses that go with it.

also correct - they tried to get into this stuff in the late 70's, didn't get very far, and didn't get it figured out [with outside help] until the early 80's. there are plenty of old bmw's on the road, but there's a honking great gap between them and anything older than ~10.

'nuff said!

it could just be incompetence, but seals are well known, the materials are well known, so there's no real reason for it to be oversight. especially if you read some of the german technical literature - they have multiple phd's crawling over every slightest detail.

germans travel the globe dude. they know /exactly/ what they're doing. and no cooling system fails on their target market owner - the one who wants a new "ultimate driving machine" every three years.

part of that is keeping it complicated thus helping to ensure that only /their/ shops work on their vehicles. why else would you have a 7mm allen socket on a brake caliper pin when 6 or 8mm would do and is widely available??? and bmw pioneered the "check engine light" concept and tried to lock it down so that only /their/ dealers could service their cars. fortunately, independent repair shops lobbied and congress stepped in on that one. [initially at least. we now have all the proprietary "tier two" codes which can be locked, but that's a war of who lobbies the most.]

the other part is that their design teams tend to work in isolation. each single component can be well designed, but having them all work together wasn't part of the original spec.

sure - it's the last of the era where they had the "good" part of the engineering figured out, and before the mba's took over.

i'm singling them out because their efforts at life limitation and lock-out are well over and above that of any other. "sealed for life" transmissions? ygbsm.

I would like to acquire some fine-strand wire but I do not have any old Fluke leads. Do you know where I can buy some? Thank you in advance for any help.

he can only afford to destroy old fluke leads because he didn't buy them, his employer did. normal mortals buy high-flex silicone wire from electronics stores or online. plenty of people sell short lengths on ebay.

As long as it doesn't fail during the warranty period they don't care.

Is this poor grade wire mandated by regulations?

G²

On Sat, 16 Mar 2013 09:52:43 -0700, jim beam wrote as underneath my scribble :

Interesting post Jim - do you have any approx. info on milage brackets on failures for transmission and other major cost BMW components? C+

>>

>>

>>

>>

>>

You've never had an old British car, have you?

nate

You're probably expecting me to argue with you, but I'm not going to. I admit to being one of those people to whom the three most important things about a car are power, handling, and braking - so I like BMWs. (although the stock brake pads suck unless you like refinishing your wheels every couple years.) Other people don't care quite so much and consider "adequate" handling to be acceptable; for them, a BMW is just too much of a PITA to run so they buy something else. (although current ride hasn't cost me anything but maintenance and an oil filter housing gasket - knock on wood.)

And if you want to talk about s**te window regulators - I actually had an A4 chassis GTI for a while. Yes, the one with the plastic doodad that was guaranteed to break. I was understanding when I read that their supplier had deviated from the spec, but was angry when the dealership said that VWoA wouldn't let them fix both windows when I brought it in for the first one... bastards... but I digress...

nate

300 HP from a 3.0 liter six - and likely as much tuning potential as the vaunted Toyota Supra - is pretty phenomenal in my book.

I would never advise anyone to buy a German car with an automatic transmission. (and you know that BMW don't actually make the transmissions correct? at least in the E9x 3-series I think the 325 autos are made by GM and the 330/335 autos are ZF-built.) Some things never change, the E28 5-series would destroy its automatic if you let it engage a driving gear, then shifted back to neutral, then revved the engine. (also a ZF box IIRC.) There's an easy solution to that problem though; learn to drive a 3-pedal car, or if you want a luxury car that your mom will enjoy driving, buy something other than a BMW. (although actually my own mom would still probably enjoy driving a BMW, as both her GTI and Miata are stickshifts.)

And as for "planned obsolescence" - you don't think that Ford, GM, and Chrysler don't deliberately revise overengineered parts?

Technically, you are correct, but in practice - it works phenomenally well. (and actually the rear suspension is a multi-link with shocks, not a strut type suspension.)

Again, it may be cheap, but it works.

Would you call a '67 Corvette with a 427/4-speed "junk" because it is not technologically advanced? I guarantee you it's still fast by modern standards, and fun to drive - and that, at the end of the day, is what matters, not whether a particular component is the most expensive, theoretically elegant part possible or not.

Hmm, I see more older Bimmers on the road than I do GM, Ford, etc. (I still see a surprisingly large number of E36 3-series and occasionally even older ones - I actually saw a 2002 on Thursday - probably the only manufacturers that I see *more* 80's era cars still running around would be Honda, Toyota, and/or VW and one would ASSume that that's because they sold more of them.

nate

Yes. This is the point that JB doesn't seem to get, nor does he seem capable of understanding *why* it makes you smile.

Quite true, and my impression is that German cars are actually better than either US or Japanese cars in this respect (as in, if maintained they will actually last *longer.*) I don't know if that is true of the ones being currently made, but it certainly was 20 years ago.

nate

yeah, after i've replaced every single component three times over, including all the stuff that should never break or wear out, the car works just great!

*) I don't know if that is true of the

there are plenty of 30+ year old bmw's out there. and plenty of 0-10 yo's. but almost nothing in between. that is by design. see above.

please don't top post, just snip.

this was back in the 80's and my prof was saying target was 100-120k miles. that's not to say it's current target, but i know several bmw owners who have had sudden failures at the low end of that range.

his job wasn't to just fix it for a certain mileage though, it was to solve the math on design life so a given target could be achieved. [it was a function of the cog tooth root tip radius.] with that solution, any mileage could be chosen. modern atomic-scale finite element analysis and cnc cutting tools have probably refined his model considerably since then.

that's only 100hp/liter. honda routinely had production vehicles at

120. non-turbo.

uh, you know that bmw /spec/ their transmission to their contractor, correct???

nate nate nate, when will you ever learn to read? i specifically stated that bmw's /method/ was pioneering but you didn't read that.

everybody else has been having their crap /wear out/ since the 50's and customers hate it. bmw's "genius" was sudden failure that took the customer unawares, /and/ presented them with a huge bill that makes the majority give up on the vehicle and buy a new one.

we'll come to fronts in a moment, but did you not read what i said about rears??? [rhetorical]

yeah, a wheel barrow works. particularly when you have tires 30% wider than a comparable vehicle that has camber control.

macpherson is garbage. by definition. go out to any parking lot and look at the inside tire of any macpherson vehicle parked with steering angled. look at the camber. look at the percentage of tire left on the pavement. /that/ is a fundamental problem that can't be solved.

macpherson is adequate for the straight-ahead and delightfully cheap for manufacturers. and that's where the story ends.

driveling excuses.

again, you can't read. you see OLD bmw's and you see modern bmw's, but you see nothing in between. the old stuff was that brief period when they had the engineering right but bmw's financials were in the crapper. then in came the mba's, so their engineering focus changed. the results are right there on the road in front of you every single day.

That's also stock. A simple flash tune (e.g. Cobb) or piggyback (BMS JuiceBox) can get you to 350-375 easily; more with a larger intercooler and freer-flowing cats/downpipes. Tony Vargas just dynoed a car on 91 octane pump gas with "full bolt ons" (generally, that means intake, exhaust, and intercooler and possibly a larger oil cooler as well) and a set of larger turbos but no internal engine work at 575 wheel HP. That sure sounds "phenomenal" to me, and reminiscent of what was being done with Supras 10 years ago or so - and keep in mind that tuners have only had since 2007 to work on the N54 engine. I suspect that there's more to be had (and in fact there are people getting more power out of them using methanol injection.)

I'm sure that BMW knows that there is more potential in that engine but they likely don't want the x35is a) competing with the M-cars or b) making so much power that they start to have internal engine part warranty claims at an unacceptable rate. (because, let's be honest, the types of people that buy 500+ HP cars tend to want to use that power on a regular basis.)

Of course, but my point is, that just like headlamps, German mfgrs. seem to punish Americans by making their automatics as shitty as possible. Stick with stickshift or DSG and you'll be fine. I'm in no way excusing the German slushboxes, but their shittiness has not been a secret for the last 30+ years.

You just perfectly described why I drive German cars and *not* Hondas.

Actually BMW tire sizes are pretty narrow comparatively, 225s on the front of a vehicle that curbs around 3400? And that's the M-sport package. BMW's tire choices are a good example of one of the instances where they have made questionable choices however; the Bridgestone run-flats do appear to have been made from actual rocks, without actually providing superior tread life.

Another thing you're not considering is that a strut-type front suspension allows room for things like big v-engines in the front of the car (remember, the current M3 uses a 4.7 liter overhead cam V-8,) and is simpler and may very well weigh less than a comparable SLA design. these are all things that must be considered when you're looking at a car designed for performance first.

Don't get me wrong, I'm not slagging Honda for using a SLA suspension - far from it - but there are several ways to peel a feline. Honda chose one way and makes some very nice handling cars (albeit FWD.) BMW and Porsche chose another and also make some very nice handling cars (but you can criticize Porsche for sticking with hanging the big heavy bits out behind the rear axle, but I suspect that that is in large part due to the Porsche faithful not accepting anything else - look at the relative failure of the 928 for example - just like we probably won't see a Harley-Davidson with anything other than a v-twin in our lifetimes.)

Hmm. Doesn't seem to hurt any of the top competitors in DTM, BTCC, etc. etc. etc. How far are the wheels generally turned in high-G cornering maneuvers, anyway? And if you'd ever owned a Bimmer you would know that any tire wear problems generally experienced are NOT in the front but in the rear, which has an "acceptable" suspension design according to you but since BMW's alignment specs have aggressive camber for better handling the rears tend to wear the snot out of the insides of the tires when the car is driven non-aggressively.

Finally, if you hate struts so much, why are you constantly slagging the Germans, who nobody can deny build beautiful handling cars (and I have never driven a car that had as nice steering feel as my old E28 chassis

535i, I suppose that that is unacceptable though because it used a recirc ball steering box which is "outdated" compared to modern R&P?) and yet I haven't yet seen you criticize Ford for the execrable Twin-I-Beam front end which was unmitigated garbage and arguably inferior to a simple straight axle, and was used pretty much unchanged save for a swap from kingpins to ball joints (a step backward, IMHO) through the mid-late 90's!

It's not an excuse, customers don't care about such things generally. What they do care about is handling and ride. If it is provided by means of transverse leaf springs and using the driveshafts as suspension links, nobody gives a crap so long as it works well.

I suppose given the choice between, say, a BMW E30 M3 and a SLA Honda Civic, in similar condition, you would pick the Civic because it has a more sophisticated suspension design, EVEN THOUGH THE BIMMER IS BETTER IN EVERY RESPECT when it comes to what matters to the driver?

Did you miss the bit where the BMW 3-series has made C&D's 10 best list for over 20 consecutive years now? And also the bit where the new Accord made this year's list as well, *despite* having the struts that you hate so much?

Where I live Bimmers seem to be one of the most popular cars (along with Toyota Camrys and various SUVs,) and I see a whole range of them on the road. The very early 3-series cars seem to have mostly disappeared, as well as most of the cars that predate the 3/5/6/7/8xx naming convention, but then again, I did see another 2002 coupe while out and about this morning. If you're looking for any particular design of 3-series however, save for the E30, you're likely to spot one within 10 minutes or so simply by driving around and looking. I probably see more E46 and E36 than I do E9x or F30s.

nate

Goes to show what you know. -----

- gpsman

he's starry eyed because he's used to that p.o.s. jeep or his employer's g.m. carp. with that as a comparison basis, i'm sure the bmw is fantastic.

This isn't an 'argument'; it's merely a discussion. Everything you said and everything I said was true.

The E39 that I own handles those three with aplomb!

The stock front pads are Jurid, with the rears being Textar, both with an FF friction & fade coefficient. They work well enough, although Akebono GG friction ratings are often used as replacement.

I use the Axxis/PBR FF pads, which dust the same color as the wheels, so you don't see the unsightly darker-colored dust of the stock Jurid pads.

The OFH often leaks on the BMW M54 engine; but luckily it's an inexpensive part, albeit a bit of a pain to DIY.

Overall, I think we're in agreement, so there's really no need for any argument. One thing about bimmer owners, they KNOW their cars!