Let's talk about your weight problem

[Camino LS6]

...global auto industry.

Why is it, despite the use of high-strength steel, aluminum, exotic composite materials, and plastic, that cars are still so porky?

How is it that modern compact cars built around a unibody structure manage to outweigh larger, much older, cars built out of thicker steel and on a full frame?

Modern gadgets? But aren't they getting lighter and smaller all the time?

And what about safety regulations? Are they to blame?

Tell me, exactly, where all this excess weight comes from. And why, exactly, we haven't been able to conquer the issue.

[balthazar]

Modern gadgets & safety items are absolutely to blame.

Glass & lesser & thinner, there's FAR less steel in modern vehicles, plus extensive aluminum; esp engine/trans.

Lighting is all plastic, bumpers are all plastic, interior is all plastic.... but pick up a moderate spool of wire and see what it weighs.

I use my '64 Catalina 4-dr sedan as a reference point: it had a full frame, an iron V8 block, decent-gauge sheet metal, was 80" wide & 213" long. Had to have less than 15 lbs of plastic. Shipping weight was 3770, and curb weight was probably about 3850. AM radio, no A/C, no PW, no PS, no air bags, no ABS, no TC, no stabilty control. If it had what a Malibu had in it AFA equipment & safety stuff, it would weigh 4800 easy.

So in discussions about vehicle weight, the emphasis erroneously falls on 'higher strength steel & more AL', cause no one ever wants to give up their power vanity mirrors...

[Camino LS6]

Which begs the question: why does that stuff weigh so much?

Compare a modern cell phone to the "brick" phone of the 80s, and I'm perplexed as to how this happens.

[balthazar]

Sheer quantity. Wire can get thinner to a point, but when you add spools and spools of it, it's a net gain.

Tire pressure monitors, back up cameras, turn signals in the sideviews, side repeater signals, ambient lighting, heated wiper fluid, heated steering wheel, 12-way power seats, rearview OnStar & temp/compass readout, auto dimming rear view, iPod connectivity, heated & cooled seats............ the features on a modern car aren't all chip programming & code like in a phone; too many tangible sensors & readouts & the like.

Edited June 18, 2011 by balthazar

[Lamar]

My first question is this: How much do these newer airbag modules weigh?

I remember when driver and passenger airbags just became required. But now with knee, thoracic, and curtain airbags (and whatever else), the weight they carry, as well as their propulsion systems, has to have been the largest culprit.

My second observation: Standard wheels on cars have grown across the board too. Remember when midsize SUVs used to ride on 15s? I know I do... mine did.

[Camino LS6]

Miniaturization should be able to ameliorate that to a certain degree.

I just refuse to believe that this issue can't be conquered.

I'd like to see a breakdown of what exact components add how much weight.

But the wheels used to be steel...

[balthazar]

general comparison: mazda miata wheel size/weight chart : http://www.miata.net/faq/wheel_weights.html

-- -- --

>>"Miniaturization should be able to ameliorate that to a certain degree.

I just refuse to believe that this issue can't be conquered."<<

I don't doubt that that has been the focus for some time.

But try and get a 3033 lb golf back even halfway to 2145 lbs (2589).

Fed regs alone won't allow it.

Edited June 18, 2011 by balthazar

[Camino LS6]

Interesting chart. It only took from 1997-2002 for the size increase to erase the weight advantage of the alloy wheels over the steel.

[Lamar]

My wheels were alloy, Camino.

To your point, though, few want steelies anymore. Many take them along with the value-leader car they buy.

[Camino LS6]

If Federal regs are the problem, they need to be reformed.

[balthazar]

So does the Fed in general. Don't hold your breath...

[Camino LS6]

I'm still wondering which components are the major culprits here.

I think that I can accept that wire weight is one of them, and that huge wheels are another.

Where is the rest?

[Camino LS6]

So does the Fed in general. Don't hold your breath...

With CAFE on the one side, and new safety regs on the other, someone needs to point out the dichotomy to those geniuses in congress.

I'd like to see GM (or any other manufacturer) detail how each safety reg adds weight to the car in direct opposition to the CAFE demands.

[balthazar]

That would definitely be an interesting/informative list.

We do it now for food....

[Z-06]

Here is how generally weights of various car components were used empirically in the past:

1. Structural Components - 30 - 35%
2. Body Panels, Glass, Grille, etc. - 15 - 20%
3. Drivetrain (including wheels and tires) - 25 - 30%
4. Interior (Seats, Dashboard, Airbags, etc.) - 15 - 20%
5. Electrical systems, accessories - 5 - 10%

Here is the note of present cars for the weight distributions above:

1. Increase in the structural stiffness demanded increase in either high strength material, which kept the weight more or less constant or increase in the structural material, which meant increase in the % of structural components.
2. Body panels, glass, etc. also went in the same fate as structural components.
3. Drivetrain also increased because of bigger engines, bigger wheels, fatter tires, complex suspensions.
4. Also increased because of more demand of amenities and comfort and safety.
5. Electrical and accessories - again known increase.

If you seek the reduction in weight, the targets should be in 1 and 3 to maximum weight loss.

[Camino LS6]

I would think that it would be in the industry's interest to make that list known in a rather public fashion.

Edited June 18, 2011 by Camino LS6

[§carlet §wordfish]

The excessive weight that goes along with safety mandates are part of why alternatives propulsion methods are being pushed so heavily.

[Lamar]

I bet if one automaker figures out how to drastically cut weight in those areas, they'll patent their idea and leave the others scrambling.

Competitive edge, or something like that.

[Camino LS6]

Here is how generally weights of various car components were used empirically in the past:

1. Structural Components - 30 - 35%
2. Body Panels, Glass, Grille, etc. - 15 - 20%
3. Drivetrain (including wheels and tires) - 25 - 30%
4. Interior (Seats, Dashboard, Airbags, etc.) - 15 - 20%
5. Electrical systems, accessories - 5 - 10%

Here is the note of present cars for the weight distributions above:

1. Increase in the structural stiffness demanded increase in either high strength material, which kept the weight more or less constant or increase in the structural material, which meant increase in the % of structural components.
2. Body panels, glass, etc. also went in the same fate as structural components.
3. Drivetrain also increased because of bigger engines, bigger wheels, fatter tires, complex suspensions.
4. Also increased because of more demand of amenities and comfort and safety.
5. Electrical and accessories - again known increase.

If you seek the reduction in weight, the targets should be in 1 and 3 to maximum weight loss.

High strength and lightweight materials have reduced the weight where they have been used and not much room is left in those areas. So, it has to be in the electrical/safety/amenities where the problem lies.

[Camino LS6]

The excessive weight that goes along with safety mandates are part of why alternatives propulsion methods are being pushed so heavily.

That just doubly pisses me off.

[balthazar]

F-Body component weight list : http://www.bfranker.badz28.com/fbody/weights.htm

[Z-06]

Here is how generally weights of various car components were used empirically in the past:

1. Structural Components - 30 - 35%
2. Body Panels, Glass, Grille, etc. - 15 - 20%
3. Drivetrain (including wheels and tires) - 25 - 30%
4. Interior (Seats, Dashboard, Airbags, etc.) - 15 - 20%
5. Electrical systems, accessories - 5 - 10%

Here is the note of present cars for the weight distributions above:

1. Increase in the structural stiffness demanded increase in either high strength material, which kept the weight more or less constant or increase in the structural material, which meant increase in the % of structural components.
2. Body panels, glass, etc. also went in the same fate as structural components.
3. Drivetrain also increased because of bigger engines, bigger wheels, fatter tires, complex suspensions.
4. Also increased because of more demand of amenities and comfort and safety.
5. Electrical and accessories - again known increase.

If you seek the reduction in weight, the targets should be in 1 and 3 to maximum weight loss.

High strength and lightweight materials have reduced the weight where they have been used and not much room is left in those areas. So, it has to be in the electrical/safety/amenities where the problem lies.

Let us be careful here Camino. There is one more factor - i.e. increased standards' threshold meant increase in requirements of strengths to meet current standards. This means increased usage of high strength materials compared to the materials that may have been used for previous standards. So weight of structural components more or less remained constant.

Currently because of high price of aluminum and high cost of molding structural titanium and CF, price of adoption of those materials is very high. Car manufacturers still use steel, albeit HS steel a lot. If the fabrication of aluminum, titanium and CF gets cheap, then we can have significant weight reduction in structural components.

[Camino LS6]

F-Body component weight list : http://www.bfranker.badz28.com/fbody/weights.htm

Interesting, but it skirts the issue a bit.

I just thought of a place we could start. GMPP offers the current Camaro as a body-in-white, that should have a shipping weight attached to it. Driveline parts could be determined the same way, and so on.

Point taken,Zo6.

[Robert Hall]

Bigger wheels and tires are definitely part of the weight gain...25 years ago, a Mustang GT or Camaro Z-28 had 15 inch wheels and tires (Camaro went to 16 somewhere in the 3rd gen)...today, 19 or 20 inch..I wonder what the weight difference is there..

[balthazar]

^ see miata wheel chart link in post #7 for general idea

Edited June 19, 2011 by balthazar

[Camino LS6]

Haven't been able to find the B-I-Y weight yet.

[balthazar]

I looked- couldn't find it either....

[SAmadei]

High strength and lightweight materials have reduced the weight where they have been used and not much room is left in those areas. So, it has to be in the electrical/safety/amenities where the problem lies.

I don't blame the safety regs on cars too much. Sure they have driven up the weights in some areas, but IMHO, its weight well spent. The use of more HS steel is fine from a weight perspective... as its not radically heavier than the standard steel used before. Z's note about higher strength/lighter weight materials coming down in price to get wide acceptance is true, but most of those materials aren't getting cheaper anytime soon. There are good reasons why they are pricy.

I partially blame the electronics in cars... as Balthy already noted, you can only trim wiring down so far. With every car having miles of wire in place, it gets heavy quick... so I blame electrical. Pull apart many modern cars and the wiring is so outrageous that it barely fits in the spaces allocated to it. Its getting to the point where the pathways the wiring runs are getting to take up a larger and larger percentage of the interior volume.

Now note, I am not for dumbing down cars completely... most smartphones are more powerful than the CPUs in cars, and smartphones are quite light. The problem is being smarter about laying out where sensors, resistive elements, etc. need to be to maximize needed features with weight.

I also believe a big contributor of weight is sound deadening. Everybody today expects their little econobox to sound like a tank when shutting doors... well, thats done by pumping a bunch of heavy tar-like material into the doors... making them very heavy. I'd love to know how much sound deadening modern cars have, weightwise, compared to cars of years past. Even in the '70s and '80s when using tar-like materials were being used sparingly, the hot rodders would go at the body with a torch to get rid of that weight... a thin coating ended up being 100-200 pounds. That's a .1 to .2 second 1/4 mile improvement. Today, nobody bothers when you an get 700hp streetable engines. I wouldn't doubt if some new cars have 500+ pounds of sound deadener in them.

Finally, I think the plastics are adding a ton of weight. Plastics are lighter than steel, but plastic piles up weight quickly, as well. Modern plastic parts are much more robust than parts in the past... to make them more rigid, unbreakable and to also absorb unwanted sounds. Look no further than the racers gutting cars of all that crap to save weight.

As far as the CAFE versus the NHTSA fighting things out, I foresee both continuing their respective missions... CAFE will require lighter cars... NHTSA will require denser cars. The problem is producing functional vehicles is not part of either mission. So the result of the rule of unintentional results is obvious... eventually the only cars legally built will be tailor made for midgets... er, uh, "little people". And all will claim victory!

[Lamar]

Ah, yes, sound deadening. We'll have to keep an eye on the weights of the next Malibu and Impala, which will ostensibly be less soundproofed than their Buick platform-mates.

As far as wiring in cars... do HIDs require thicker wire than halogen setups? And I figure that all the LEDs are wired in parallel, which can also add up...

[Justin Bimmer]

250 feet of 12/2 Romex weighs about 21 lbs.

Edit: An article on how BMW is testing aluminum wiring to replace copper wires.

[SAmadei]

As far as wiring in cars... do HIDs require thicker wire than halogen setups? And I figure that all the LEDs are wired in parallel, which can also add up...

Its not tremendously thicker, as least on the retrofits I've seen. OEM setups might use heavier to be on the safe side. LEDs, in theory should need less wiring than incandescent... but considering how much heat some LEDs give off, they are not all created equally.

250 feet of 12/2 Romex weighs about 21 lbs.

Your car uses Romex? ;-) That would be interesting.

The weight of the electrical is not just in the copper... but also the covering... lighter gauge wires use comparably thick coverings. Also motors/speakers/etc. have miles of wire spooled up in coils and magnets are heavy, as well.

Edit: An article on how BMW is testing aluminum wiring to replace copper wires.

I can't see that being worthwhile. Aluminum wiring in a home is such a PITA, its easiest to rip it out. Its worth the weight/hassle ratio in a aircraft... the only way I see it worth doing it in a car is if the price of copper spikes again. Which it may, I might add... we have a severe worldwide copper shortage.

[balthazar]

Aluminum came & went in an eyeblink (approx a decade) as far as being in code for home wiring. It corrodes where joined with dissimilar metals, and that can cause enough heat where fire can start. AL expands more than copper, which tends to loosen connections sooner. AL also has about half the conductivity of copper and a third the tensile strength. It's NOT a good move really on any front (except weight). Hopefully BMW doesn't cut their corners that hard.

[Camino LS6]

Aluminum wiring is bad news indeed - not a viable solution.

[Justin Bimmer]

I just went searching for an example of wire weight. I have no clue what romex is. LOL

[Robert Hall]

I just went searching for an example of wire weight. I have no clue what romex is. LOL

Never heard of Romex either, but the magic of Google turned up:

http://en.wikipedia.org/wiki/Romex

A trademarked brand of non-metallic sheathed electrical cable developed by the former Rome Wire Company in 1922, and now produced by Southwire

[balthazar]

Romex is what's running thru your post WWII house, making everything cost you money.

[Robert Hall]

Romex is what's running thru your post WWII house, making everything cost you money.

Cool..my house was built in 1952, probably still has most of the original wiring...$400 electric bill last month, probably be about that through Sept when it gets 'cool' again.

[Camino LS6]

Dare I mention knob and tube?

[67impss]

If you want to lower the weight of the wiring & electrical system you need to raise the operating voltage. The higher the voltage the lower the amperage needed to operate most systems. GM had looked into a high voltage electrical system 72 volts DC IIRC. I don't know if the BAS system was the outcome but I think that was part of it. If fully implemented it would lower the weight. Just think no starter or alternator only a generator/starter component thinner wiring smaller wiper,blower & hydrolic motors ...

[SAmadei]

Romex is what's running thru your post WWII house, making everything cost you money.

Thats going to confuse the civillians... Romex has changed over the years, but modern Romex is the thickish, plastic sheathed power cable you'll find in Lowes or Home Depot. Romex for in-wall installation is labelled NM. If the cable has a metallic sheath, thats BX... which is used for other purposes.

Just looking at a post-WWII house, you will likely be also looking at Romex, but earlier form of Romex that has a fabric-like weave. My '59 vintage house has that. Sometime between '59 and '78 the modern Romex become the standard... I'm not sure when.

I can't believe some of you guys didn't know what Romex was.

[balthazar]

Yea- I was certainly generalizing.

The fabric-wrapped stuff is neat (except when you open it up; lot going on in there).

BX is awesome; obviously not as easy to work with from the homeowner standpoint but the meese can't chew thru it.

[Robert Hall]

I can't believe some of you guys didn't know what Romex was.

Unless one is an electrician, one is probably not going to know the name...like with any profession, there are brands and arcane terms that aren't generally known by the GP.

[SAmadei]

I can't believe some of you guys didn't know what Romex was.

Unless one is an electrician, one is probably not going to know the name...like with any profession, there are brands and arcane terms that aren't generally known by the GP.

I'm not an electrician. I agree that there are a number of brands and arcane terms that aren't known by the general public, but Romex has transcended that. One does not have to be an office worker to know what Xerox is. Nor does one need to be a Pharmacist to know what Oxycontin is.

We just got through the biggest flipping/renovation era in US history. If you had any electrical work done or you watched HGTV/DIY networks, you'd hear the term. My GF knows what it is and her condo is all BX.

Getting back to the subject at hand... Romex is not the same wire your car uses. Cars typically use several feet of thicker, stranded cables for battery cables, but most automotive wiring is considerably smaller. Of course, there is more of it. The typical hyperbole ranges from 2 miles of wiring to 50 miles of wiring to (no way) 200 miles of wiring in a single car.

All I know is I have some OLD car complete wiring harnesses in a box and due to the sheath, connectors, clips, protectors, etc., even the wiring in a '70 fullsize gets pretty darn heavy... 70-80lbs. To include all the lights, sensors, motors, speakers and the extra mileage of copper, sheath, connectors, clips and protectors, I can see there being beyond 500 pounds of "electrical" in a car easily.

[pow]

Don't really see the correlation between increased weight and safety regulations. Cars are crashed into walls or deformable barriers to simulate two vehicles of similar weight colliding into one another, not an X5 into an Aveo. In fact, mass without a corresponding increase in stiffness would compromise crash test performance. The same goes for side impacts. A stiff lightweight car just bounces away from the perp who hits you, whereas in a heavy car, the T-boner has a chance to "dig" into the side of your vehicle before hurtling it off to the side of the road. If a Traverse is about to hit me from the side at 25 mph, I'd rather be in a 2,000 lb smart fortwo rather than a 4,000 lb Crown Vic, honest.

Also, rollover scores are determined by strength to weight ratios, not the actual strength of the roof alone. Weight in rear crash tests by the IIHS don't matter because they're tests of the seats themselves, not the car.

Edited June 26, 2011 by pow

[SAmadei]

Don't really see the correlation between increased weight and safety regulations. Cars are crashed into walls or deformable barriers to simulate two vehicles of similar weight colliding into one another, not an X5 into an Aveo. In fact, mass without a corresponding increase in stiffness would compromise crash test performance. The same goes for side impacts. A stiff lightweight car just bounces away from the perp who hits you, whereas in a heavy car, the T-boner has a chance to "dig" into the side of your vehicle before hurtling it off to the side of the road. If a Traverse is about to hit me from the side at 25 mph, I'd rather be in a 2,000 lb smart fortwo rather than a 4,000 lb Crown Vic, honest.

Smart vs. Crown Vic is not a real good comparison, as the Crown Vic's crash protection is about 20 years obsolete...but...

You're not taking into account the most basic bits of physics. That Smart car will result in less damage to the Smart, but much more damage to the occupants, as the act of "bouncing off" will generate an obscene amount of G forces. Due to its light weight, the G forces applied to the other occupants is relatively low.

The Crown Vic will not live to drive again, but the force applied to "digging in" is that much less force that is applied to the occupants of either car. And assuming the car hitting the Crown Vic is of similar size, both sets of occupants will experience roughly the same G forces.

The infamous video of the Smart being run into the crash barrier at 70 is amazing, but as well as the car held up, even the professionals in the video mention the chances of survivability of passengers would be very low.

Engineering and high strength steel have not trumped F=ma.

[pow]

Don't really see the correlation between increased weight and safety regulations. Cars are crashed into walls or deformable barriers to simulate two vehicles of similar weight colliding into one another, not an X5 into an Aveo. In fact, mass without a corresponding increase in stiffness would compromise crash test performance. The same goes for side impacts. A stiff lightweight car just bounces away from the perp who hits you, whereas in a heavy car, the T-boner has a chance to "dig" into the side of your vehicle before hurtling it off to the side of the road. If a Traverse is about to hit me from the side at 25 mph, I'd rather be in a 2,000 lb smart fortwo rather than a 4,000 lb Crown Vic, honest.

Smart vs. Crown Vic is not a real good comparison, as the Crown Vic's crash protection is about 20 years obsolete...but...

You're not taking into account the most basic bits of physics. That Smart car will result in less damage to the Smart, but much more damage to the occupants, as the act of "bouncing off" will generate an obscene amount of G forces. Due to its light weight, the G forces applied to the other occupants is relatively low.

The Crown Vic will not live to drive again, but the force applied to "digging in" is that much less force that is applied to the occupants of either car. And assuming the car hitting the Crown Vic is of similar size, both sets of occupants will experience roughly the same G forces.

The infamous video of the Smart being run into the crash barrier at 70 is amazing, but as well as the car held up, even the professionals in the video mention the chances of survivability of passengers would be very low.

Engineering and high strength steel have not trumped F=ma.

This may be true of a head-on collision, but in a side crash, the integrity of the passenger compartment is far more important than the mass of the vehicle. I'd rather be violently thrown around the cabin than to be crumpled upon impact. Granted the Crown Vic is an ancient vehicle, and you can have heavy vehicles with stiff structures, but the point is that weight doesn't play a role in government and IIHS crash tests.

http://www.iihs.org/ratings/image.ashx?rh=657&id=2

[SAmadei]

This may be true of a head-on collision, but in a side crash, the integrity of the passenger compartment is far more important than the mass of the vehicle. I'd rather be violently thrown around the cabin than to be crumpled upon impact. Granted the Crown Vic is an ancient vehicle, and you can have heavy vehicles with stiff structures, but the point is that weight doesn't play a role in government and IIHS crash tests.

http://www.iihs.org/...shx?rh=657&id=2

I'm not discussing frontal collisions.

In a side impact, integrity of the passenger compartment is important... but beefing up that structure increases mass. And when testing, the entire mass of the Crown Vic is still used to dissipate the force of the impact.

Notice that the Crown Vic is not fastened to the ground... that would have taken the weight factor out of the equation. The entire Crown Vic is accelerated, therefore weight plays a role in the crash test.

Now, if the vehicle has a sufficiently weak structure, then I suppose the weight works against the design... but what you can't see in a video is the actual forces being recorded by the dummies. If that weight slowed down the sled to reduce the forces on the passengers, then also plays a role in the crash test.

F=ma is true in ANY collision. Your acceleration vector will be determined in part by weight. If the G's experienced are great enough, even with a seat belt, your internals will rupture.

If you don't want to be crumpled upon impact, you better choose a car that has extra space inside (heavier vehicle) or has more side protection (heavy side beams). Weight therefore plays a role in your purchasing habits for safety.

[pow]

This may be true of a head-on collision, but in a side crash, the integrity of the passenger compartment is far more important than the mass of the vehicle. I'd rather be violently thrown around the cabin than to be crumpled upon impact. Granted the Crown Vic is an ancient vehicle, and you can have heavy vehicles with stiff structures, but the point is that weight doesn't play a role in government and IIHS crash tests.

http://www.iihs.org/...shx?rh=657&id=2

I'm not discussing frontal collisions.

In a side impact, integrity of the passenger compartment is important... but beefing up that structure increases mass. And when testing, the entire mass of the Crown Vic is still used to dissipate the force of the impact.

Notice that the Crown Vic is not fastened to the ground... that would have taken the weight factor out of the equation. The entire Crown Vic is accelerated, therefore weight plays a role in the crash test.

Now, if the vehicle has a sufficiently weak structure, then I suppose the weight works against the design... but what you can't see in a video is the actual forces being recorded by the dummies. If that weight slowed down the sled to reduce the forces on the passengers, then also plays a role in the crash test.

F=ma is true in ANY collision. Your acceleration vector will be determined in part by weight. If the G's experienced are great enough, even with a seat belt, your internals will rupture.

If you don't want to be crumpled upon impact, you better choose a car that has extra space inside (heavier vehicle) or has more side protection (heavy side beams). Weight therefore plays a role in your purchasing habits for safety.

Not disputing that mass matters in overall vehicle safety, particularly in head on collisions. What I'm saying is that it doesn't matter in the context of the crash tests that the IIHS and NHTSA do. The Crown Vic is at a disadvantage because of its weak side structure and high curb weight. The matter of mass is secondary when you consider the occupants inside have NO survival space, i.e., the B-pillar is where your right shoulder once was. Speaking of forces, the dummy in the Crown Vic recorded forces on the pelvis SIX times higher ("Poor") than in the fortwo ("Good").