06-05-2019, 04:40 AM | #23 | |
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In the UK we have a TV program called "Watchdog" who take on cases like this and air it to millions of viewers. The way things are going I may be approaching them for some help. I'm sure BMW would not like that. |
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06-05-2019, 04:43 AM | #24 | |
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06-06-2019, 07:02 AM | #25 |
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This photo of the front M Sport brake assembly clearly shows what the problem is. The wide open top is a magnet for catching stones and the bottom of the shield bends in towards the disc closing the gap and trapping the stone. The bottom of the shield can't be bent outwards because of the track rod end which is right up against the shield.
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06-06-2019, 07:57 AM | #26 |
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I'm not an automotive engineer, but as hobby I often fix and correct issues they've caused on my project cars. So I tend to give them the benefit of the doubt, until it's been proven they've designed a defect that needs addressing.
That being said, the photo above creates several questions and concerns for me. Why is the gap so large between the rotor and shielding? Why does the shield flare out at the top, but in at that bottom (I understand the steering rod clearance issue)? I know I'm probably wrong, but it almost looks like that thing is installed upside down and backwards. Why doesn't it follow the most prevalent design style for this component? See my examples below: |
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06-06-2019, 09:07 AM | #27 | |
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06-06-2019, 09:08 AM | #28 | |
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I am informed that the new 3 series M Sport brakes are exactly the same design. That car is a big seller so I'm sure it will only be a matter of time until many other owners start to complain as well. Let's wait and see what happens. |
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06-06-2019, 09:19 AM | #29 |
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And here is a photo of the rear M Sport brakes. Better than the front ones but still not great due to the gap not being closed off at the top like other designs that I have seen.
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06-06-2019, 03:30 PM | #30 |
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I'm no expert, but that seems like a huge difference compared to the front brakes. Most stones would simply fall through (if I'm looking at the photo correctly) where with the front brakes they wouldn't.
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06-06-2019, 04:21 PM | #31 | |
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06-07-2019, 10:38 AM | #32 |
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My Z4 finally reached the stage of delivery (Awaiting Carrier Assignment), where the VIN is active on the BMW Owners site. I'm able to download the Driver's Guide, and immediately found this in the FAQ section.
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06-07-2019, 10:59 AM | #33 | |
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Shame on BMW for trying to shirk their responsibilities. Last edited by Jim S; 06-07-2019 at 11:31 AM.. |
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06-09-2019, 01:22 PM | #35 | |
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Next time I will be calling out BMW Assist to remove the stone. |
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06-09-2019, 03:25 PM | #36 | |
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This is one of those things there seems to be a legit design reason for, but leads to brake noise like ceramic. Maybe I've gotten complacent but honestly it's like shifting for me now, I just clear the rock unconsciously, just not that big of a deal. |
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06-09-2019, 03:26 PM | #37 | |
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This is one of those things there seems to be a legit design reason for, but leads to brake noise like ceramic. Maybe I've gotten complacent but honestly it's like shifting for me now, I just clear the rock unconsciously, just not that big of a deal despite happening frequently. Designs have trade-offs and this seems like one of them. |
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06-09-2019, 03:37 PM | #38 | |
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06-09-2019, 03:46 PM | #39 | |
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Have you had an M car, or any performance car before? Are you aware of these kinds of trade-offs? "it's jerky! the transmission shifts hard! it's loud!" Maybe you're just finding out you're not a performance car guy and not willing to accept the trade-offs they have. Lord knows BMW continues taking away performance features in favor of luxury these days ... Performance cars have trade-offs, no shame in moving to Lexus if that's more your jam. |
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06-09-2019, 04:12 PM | #40 | |
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06-09-2019, 05:55 PM | #41 | |
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Your complaint thread prioritizes comfort over performance (I don't hear you complaining about brake fade), despite the fact you decided to buy a performance oriented car, and now you'd like BMW to give you the BMW luxury convertible you didn't decide to buy. To lay it out more clearly for you: (1.) Is it reasonable to expect performance oriented cars to have trade-offs of luxury/comfort for performance? (2.) If yes, should braking be one of those places we could expect those performance-for-luxury trade-offs? (3.) If yes, are fade-resistant brakes worth the trade off of luxury/comfort in this Z4? If yes, then stop & congrats (4.) If no, trade for the 2er vert or are you willing to pay more for brakes with high performance and comfort? (5.) If yes, then aftermarket. Personally M-performance brakes are a fine trade-off to me, and I can confirm the brakes on my M4 are monsters, and that's my top priority, everything else is gravy. While I'd prefer my brakes not be prone to getting rocks caught, I also understand perfection is impossible and we shouldn't let the perfect be the enemy of the really, really good. TLDR: If your complaint of performance brakes is performance, that's reasonable; if your complaint of performance brakes is comfort, that's not reasonable. And, yes, I do understand you believe perfection is reasonable for the price you've paid.
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06-09-2019, 09:22 PM | #42 | |
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I get the idea of trading off comfort for performance - thats just not whats happening here. Last edited by SgtGigglebox; 06-09-2019 at 09:27 PM.. Reason: better |
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06-09-2019, 11:14 PM | #43 |
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I had the same issue on my 2017 M4. I complained to my service department and they found out BMW redesigned the brake shield since my car was produced. They installed the new ones and I haven’t had any problems since. I can’t believe BMW hasn’t learned their lesson from the F80/82.
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06-10-2019, 11:47 AM | #44 | |
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There is no reason to believe that the OP's stated issue/concern is a function of all high performance braking systems; there are many other cars with high performance brakes that don't seem to have a problem trapping rocks between the rotor and dust shield. My Jaguar has their "superperformance brakes" and there haven't been any reported issues with stone trapment in the past 4 years that I've been a member of that forum... 2 cents, Dave |
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