Control Arms: Aluminum or Steel?

[Scott C]

my aluminums were replaced by steel - cant tell the difference. Just get M5 bushings - now that is a difference.

[E34-520iSE]

I've got Alu. arms - I haven't noticed any difference at all!

Sorry,

Shaun M

[EngPhys09]

I need to replace my control arms on my car and i'm curious whether to get Aluminum Lemforder or Steel Lemforder?

Is there any obvious benefits to Aluminum? Beside the fact that its lighter? I assume this would imply that they are weaker?

The car is never going to see a track and there is about a $60 price difference between the steel and the aluminum. However the car is lowered
Anybody use aluminum or is it best to stick with steel?

Aluminum
http://image.autopartsonlinecanada.com/live/L200030365LEM.JPG

Steel
http://image.autopartsonlinecanada.com/live/L200030428LEM.JPG

[repenttokyo]

don't assume that aluminum is weaker than steel :) but i do not remember which ones i ordered, and i ordered mine a mere month ago!

[EngPhys09]

don't assume that aluminum is weaker than steel :) but i do not remember which ones i ordered, and i ordered mine a mere month ago!


Well obviously it depends on the aluminum that is used i just was wondering if there are any real perks

[gmannino]

Generally steel is much harder than aluminum. Ever try to cut aluminum vs steel? Big difference. Of course, there are many grades of both metals.

This is a good question, I am curious. I would lean toward aluminum for lighten the car and many motorsports use aluminum parts.

[Bimmer Nut Ed]

Aluminum arms are more expensive.

Generally speaking, the arms are the same strength. You can see that the aluminum ones are thicker, because as mentioned, aluminum is not as strong as steel. Therefore they make the arms thicker/bigger.

The main benefit is reduced unsprung weight. That's why many look for lighter wheels for their cars. In my opinion, reduced unsprung weight only helps when you are hitting bumps and potholes. Lower unsprung weight means less resistance to move, smaller impacts. I'm sure thats not the best technical explanation, but you can't say I didn't try.

[EngPhys09]

Aluminum arms are more expensive.

Generally speaking, the arms are the same strength. You can see that the aluminum ones are thicker, because as mentioned, aluminum is not as strong as steel. Therefore they make the arms thicker/bigger.

The main benefit is reduced unsprung weight. That's why many look for lighter wheels for their cars. In my opinion, reduced unsprung weight only helps when you are hitting bumps and potholes. Lower unsprung weight means less resistance to move, smaller impacts. I'm sure thats not the best technical explanation, but you can't say I didn't try.


Dont worry I'm in my 4th year of 5 for my engineering degree, i understand all this unsprung weight issues, size difference and properties of Al vs Steel.

Do you have Aluminum control arms on your car?
I dont really want all talk, I know the ideas but I just want someone who has them to tell me yes it was worth the extra cost

[Blitzkrieg Bob]

Dont worry I'm in my 4th year of 5 for my engineering degree, i understand all this unsprung weight issues, size difference and properties of Al vs Steel.

Do you have Aluminum control arms on your car?
I dont really want all talk, I know the ideas but I just want someone who has them to tell me yes it was worth the extra cost

My ///M5 and my Touring have the Aluminum arms and my 525 has steel.

I can't tell any difference between the two on the ride of the car. But the shiny silver arms are nice to look at when you're under the car.

[repenttokyo]

Generally steel is much harder than aluminum. Ever try to cut aluminum vs steel? Big difference. Of course, there are many grades of both metals.

This is a good question, I am curious. I would lean toward aluminum for lighten the car and many motorsports use aluminum parts.


how easily something can be cut isn't always an indication of its resistance to other stress.

[EngPhys09]

My ///M5 and my Touring have the Aluminum arms and my 525 has steel.

I can't tell any difference between the two on the ride of the car. But the shiny silver arms are nice to look at when you're under the car.


Thats the other plus is no rust!!! However the nut will still likely rust :(

[Craig Wright]

My E34 is lowered with the Sachs kit, and I have steel arms w/ the upgraded bushings. It's very tight and corners well! It's too old to subject it to track conditions, so it only sees spirited driving on the back roads of Ohio. My /E39 touring has the factory sport suspension. I prefer the handling of the e34 on the backroads. The E39 is better suited for the long distance travels.

[BigKriss]

i went with alum also. lower unspring weight

[EngPhys09]

Hmm seems like I'll save some money and buy some steel control arms. Considering there is no real plus to Al

[genphreak]

Hmm seems like I'll save some money and buy some steel control arms. Considering there is no real plus to AlThe main plus is that they look nice every time you lie down on the road and look at the front of the car. Since I do this on a regular basis...

Seriously, if you are the kind of person that cares what people think when you drive by (I don't get this concept personally,perhaps it is related to modern doof doof mentality?), perhaps you can gain value from the upgrade by the impression al LCAs leave on the pedestrians, every time you mow them down...

That said I have them on my e34s. 2 reasons- one, I believe the non-lemforder alloy LCAs are almost as good as the Lemforder steel LCAs, and;

I usually import my parts personally via airmail, so I see less difference due to the freight cost (lower weight) of the al LCAs.

Anyone had a bad experince with the non-lem alloy LCAs?

[e34.535i.sport]

I ordered Aluminium arms with m5 bushes and recieved them recently - I was amazed at the difference in wieght between the Alu and Steel! I don't know hoe much you'll 'notice' when driving but it all helps.

And I agree, they do 'look' cool under the car too!

[Ferret]

If your roads are ****, like in the UK, if you've been driving your car for a loooong time and are used to its handling - you can notice a small difference. Over potholes and uneven surfaces the steel arms tend to plod around and skitter more - weird as the alu arms are lighter etc you'd expect them to jump more.

I went alu->steel on my TDS tourer as it was the cheap option - but the car never quite felt the same on the front end again.

Also I was told by a seasoned indy that you'll notice very little difference between the two, except on the track where the alu arms are more prone to flexing under load :)

[bimmo_2007]

I asked some mechanic, he said Alum. gives more stability over bumps.:D & that's why they are more expensive.