Plastic Front Suspension?

[Drivesolo]

Possibly! My experience with BMW's began and ended with an R69S.
Here's the description of the part above:
BMW 3-Series 2018, Control Arm Strut by Lemfoerder®. In order to ensure safe vehicle handling, even in the event of extreme roadholding, it is important that the movement of the wheels is transferred quickly and precisely. For this purpose, intelligently designed control arms with joints are used within the wheel suspension. The control arms assume the task of wheel guidance and frequently also transfer spring, damping and stabilizer forces.

Right, that's for the lower control arm (linkage) for a F-chassis Bimmer. A strut suspension for a passenger car doesn't have an upper control arm, just a big beefy lower control arm. You only get an upper control arm on multi-link and double a-arm suspensions (Model 3).

 

[JimmyAZ]

Personally this seems like a non-issue. The upper control arm doesn't take ANY weight of the vehicle. That's the least-stressed part of the suspension. It only needs to guide the alignment as the strut travels. Nice job, Tesla, for reducing weight where needed!

 

[Daniel in SD]

Personally this seems like a non-issue. The upper control arm doesn't take ANY weight of the vehicle. That's the least-stressed part of the suspension. It only needs to guide the alignment as the strut travels. Nice job, Tesla, for reducing weight where needed!

Looks like they made it too light though. They had to weight. In all seriousness it's probably fine.

 

[Snerruc]

Corvette has used plastic ( fiberglass) for springs for years without problems. That’s a pretty severe usage.

 

[JimmyAZ]

Yeah I don’t think it’s a problem if they’ve used them in all the miles and all customer cars and we’re bit hearing about any problems.

 

[outdoors]

View attachment 273064 This is what you are all talking about. Remember suspension has feelings too. If I were it. I would be saying please try me before you just discard me. I love bumps. Like millions of them.

A while back when all the talk was how stiff the suspension is/was. It just goes to show your the plastic was right in front of me. It could have been made in platinum. I would have never known or cared. As long as it goes down the road straight.

 

[N5329K]

If, as someone here mentioned, the same plastic part lives and works well enough in a Model X, it should be OK in a smaller, lighter car. The engineer doing the disassembly and exam in the video, however, expressed honest surprise to find plastic being used in an upper control arm. That meshed with my anti-plastic prejudices for important, safety-related parts. This is one reason I will never build my own airplane. I'd double the size of every fastener and the thing would never fly.
He went on to say the same part is steel in a Model S, so perhaps he didn't know plastic was used in the X (is it really?), and ended with "We'll see how this works out."
Which is certainly true.
Watch the whole series to learn more about Model 3, and how it all goes together. Well worth the time spent.

Robin

 

[ℬête Noire]

The engineer doing the disassembly and exam in the video, however, expressed honest surprise to find plastic being used in an upper control arm.

You selectively filtered out the part where he mentions it kinda makes sense because that part of the suspension assembly doesn't get much stress on it?

 

[N5329K]

You selectively filtered out the part where he mentions it kinda makes sense because that part of the suspension assembly doesn't get much stress on it?

No, I heard that. As well as "Hmm. Never saw that before." In engineer-speak, that is not usually a compliment.
I imagine some old Cretan aeronautical engineer might have stood by Daedalus, saw those wax wings and said, "Hmm. Never saw that before."
Good to the last drop, though.
Robin

 

[ℬête Noire]

No, I heard that. As well as "Hmm. Never saw that before." In engineer-speak, that is not usually a compliment.

You heard it but then chose to just dismiss it and light your hair on fire.

Yeah, you're noise. Good bye.

 

[N5329K]

You heard it but then chose to just dismiss it and light your hair on fire.

Yeah, you're noise. Good bye.

Ta ta.
Robin

 

[Twiglett]

sounds like the sky is falling again - only just got it put back up from the last time

 

[03DSG]

I think the front upper control arm in composite is a great idea in the 3’s double wishbone (double A-arm) front suspension. The vast majority of the vehicle load is on the lower control arm. The upper control arm is basically a locating arm. Prevents corrosion as well.

 

[Canuck]

Here's why it's made of plastic:

 

[Drivesolo]

Apologies from bringing an old thread back from the dead.

Not sure why it was thought that the upper control arm was plastic. Last night I was testing the fitment of some wheels. I took a look at the front upper control arm and as soon as I touched it I could tell it was metal. I used a magnet to confirm that is was indeed steel. The front upper control arm IS NOT plastic, it is painted steel.

 

[Daniel in SD]

Apologies from bringing an old thread back from the dead.

Not sure why it was thought that the upper control arm was plastic. Last night I was testing the fitment of some wheels. I took a look at the front upper control arm and as soon as I touched it I could tell it was metal. I used a magnet to confirm that is was indeed steel. The front upper control arm IS NOT plastic, it is painted steel.

I'm pretty sure the picture above shows a plastic upper control arm. Maybe they changed it?

 

[smartypnz]

Just one word.......
Plastics

 

[Drivesolo]

I'm pretty sure the picture above shows a plastic upper control arm. Maybe they changed it?

It is a single stamped steel component with a plastic inserted 'lattice' under the bottom. The front upper control arm is steel.

 

[DIYDanCars]

Aren't those the lower arms? I think they see a lot more stress than the upper arms and yes I'm told they should be replaced every two years if you corner hard. Very bad when the front wheel detaches! Another reason why I will never own a BMW. haha

I agree. My BMW experience was nothing short of a nightmare. Too much cheap plastic BS used on important sub systems that will get brittle and break with heat and age. Nothing screams quality like plastic. lol!

 

[Ohm’s Law]

Plastic has come a LONG way since 1970.

Ever seen what it takes to break a plastic upper or lower control arm on a high end RC car? I have.