GM has given up on aero fender skirts
 

GM director of design, Ed Welburn, has conceded that they will definitely not be using rear fender skirts because of many production, cost & marketing drawbacks, even if they do reduce drag & improve fuel economy.
Clearly for the OEM industry, people just don't like them on their designs.

The aftermarket industry and fellow eco-modders can & will fill that 'void'.


Rear fender skirts look great, but flunk in other ways

How the Hell do skirts increase tire pressure, increasing the probability of a tire failure? :confused:

They act like skirts will add half a grand to the MSRP. I doubt it.

If they wanted to narrow the rear a couple inches it really wouldn't make that much of a difference imo. People don't push their cars to the limit anyhow. And cargo space? Please. With the kind of styling shapes they think up for crap it won't matter that much in the long run either. Of course the rear seats will be a little narrower but most seats on 2+2's and small cars are small anyway.

Also, with FWD it would be super easy to narrow the rear track.

To be fair, our collective understanding of what happens around the wheels and wheelwells (for some reason Europeans call them wheelhouses, like the Titanic) is just getting started.
For instance, it seems to be a better use of a pair of skirts to put them on the front. (shocking! shocking! It's got to look like an Ecocar!) Airflow at the rear is pretty well settled down, by comparison. (Regert)
Then there's the issue of jetting vortices at the road/tire junction. The front seems to be an area of rapidly changing pressures and velocities, and even a skirt is only a partial solution.
Then there's all the stuff like brake cooling, where the front has to do most of the work, and dissipate most of the heat.
I, for one, would cut them some slack.

IMHO the hybrid & EV vehicle niche will still get them. The more 'progressive' designs & shapes, ala the Prius, were to their marketing benefit. It became a design brand icon, that the enlightened buying public was looking for that recognizable aero template. EV1 & the Insight had fender covers that became their 'efficiency' badges. The mainstream consumers may bypass this aero device but FE buyers will recognize and choose these options.

"Production and cost drawbacks"? How can they say something like that, do they think their customers are morons?

Why not have them as an option and satisty those who refuse them and those who want them?

If you have a heavily loaded tire it will tend to get hot. Pressure increases in a hot tire. If you have an underinflated- you know, like just about everybody drives around on- heavily loaded tire it will get even hotter. Yeah the pressure increase there would be nice but the heat is the worst enemy. If you then partially enclose it you can expect it to heat up more. If you partially enclose it and then use the brakes heavily I'd imagine that wheel well will really heat up. GM HAS to design for the worst case scenario, otherwise idiots and lawyers will sue.

Removeable skirts are fiddly. I think even if you have a robust mounting design, it is in a location often fouled by dirt, mud, and ice.

They'd probably want to paint it body color. Painted parts add cost disproportionatly.

It is undesireable to have front and rear tracks that mismatch by a little- I'd say, by less than 2x the width of the rear tires. This is because on a soft surface (yes people still drive on dirt roads in America) if the rear tires don't fall squarely into the front tires' tracks, they get squirrely. Believe me, it sux.

As always, if someone wants them badly enough, they can make them or the aftermarket can fill that void. (PUN!)

Last but not least, they aren't as great an aero device as we'd like. Mfgs have to scrutinize the pros and cons way more than the likes of us.

If you design a car to have wheel skirts and leave them off, it looks funny.

http://farm5.static.flickr.com/4046/...ff79cba396.jpg

If you design a car to have open wheel wells and later add skirts, it looks funny.

http://img261.imageshack.us/img261/5697/sideviewof5.jpg

(No offense to Sulfuric- I'd post the Probe if the concepts didn't have covered wheels)

So we come to a crossroads: does the company want to go out on a limb and build a car with skirts that people may or may not like? Or do they just build another "safe" car that people are more likely to buy?

I'd like skirts to come back, and to have more EV1's and Insights, but in this economy I don't think companies are ready to take that risk.

This article just goes to show how limited that the field of automotive engineering is in terms of forward intellectual thinking.

I honestly think that skirts WILL be standard on vehicles in the next 10 years. As communities such as ours become more prevalent, the communal knowledge that we convey does as well. It sounds weird, but I believe that consumer comprehension is necessary to see this through. I say this because in order for consumers to demand something, they must first understand it.

It all comes back to the fact that automakers are scared to be TOO innovative for fear of consumer rejection.

Correction there ... it's automotive styling, not engineering. As in, marketing gurus, focus groups, planned obsolescence, consulting the legal department 137 times over, tailfins...

At first look, that tire pressure comment in the article sounds like total horsepucky. But, what Frank Lee said holds some weight... it boils down to ease of use, saleability, and liability.

Basically the styling boss of GM went the diplomatic route, and didn't say "studies show our customers are stupid and never check their tire pressures until the rim is rolling directly on the sidewall folded over onto the pavement".

Skirts are a cheap scapegoat, but they will also make it harder for people to check the condition of their tires as far as wear, and air pressure goes (even if, in general, people neglect to do that when they're totally exposed in open fenders).

Of course, a spike up to $5/ga gasoline could change opinions markedly...

oh come on.....don't use a picture of the citron with a hard on!!!!!!!! :eek:
Hydralics must be stuck!!!!;)
A Cetrion looks much better hunkered down. When i was in hs, one of the hippie :cool: boys (73-75) had one. This was in dallas tx. never forget the day he made it go up & down for us........

and of course a skirt looks silly with some stupid name.....:eek:....oh scratch that:rolleyes:

GMs best bet is to stick with building cars people want to buy.

When gas hits $5 a gallon cars that consumers considered butt ugly cars will be a little more appealing, but until then its going to be the same as always.

Beauty is as beauty does. Hopefully I can build a car that lowers consumption to ~100Wh/mile:
http://img.photobucket.com/albums/v7...8at71406AM.png
Since aerodynamics are the overwhelming majority of the energy used to move the car at most speeds (~35MPH and up), the biggest savings in efficiency are in lowering drag.

Does he still have the job ?
He should be out after this rubbish hit the news.

Oh boy.
All Insight I owners are now running to their cars pulling off the skirts !

It obviously costs more than to produce nothing.
But they haven't been falling off Insights.

Pick one :
- tires are oversized anyway
- slightly narrower track on the rear reduces drag
- the amount the underbody needs to be pulled out isn't an issue, as car manufacturers and the aftermarket have been doing it for decades with optional sideskirts between the wheels and plastic fender extenders for souped up adventure versions of plain cars.

Slightly, and you gain it back + a bit extra drag reduction because of the covers.
Besides, quite a few folks on here have done it without adding extra area.
If they can do it, surely a GM engineer can do it if he's worth his pay ?


Those Honda guys had it all wrong then.
Same for the Citroen blokes and countless other manufacturers who have used wheel skirts in the day.


If you wonder why GM USA doesn't have efficient vehicles, you can now pin a name on it : Welburn.

We'll burn more gas

^^ I think you're right. That's why new ideas don't come around; someone doesn't like them. Everyone doesn't like something, though, and you can imagine what would happen to Camaros if an ecomodder type got the job. More people like Camaros than Priuses. More attention is given to sports cars.

Marketing, Legal or Styling? They're different things. I'll say right now most stylists aren't into wheel skirts, but I can't speak for the focus groups.

Sometimes it's nice to have suspension travel :thumbup:

My favorite use for a Citroen (or damn near any car, come to think of it).

http://3.bp.blogspot.com/_HqN1Sz9e5u...gal+1972-2.jpg

Those cars were driven hard, and even with skilled mechanics they did not want to take off fender skirts during stages. This brings up a good point because most drivers will not want to remove skirts in the middle of the Mojave or in a snow bank in South Dakota or in South Detroit... you get the... "drift". :p

Yeah, and stick with building what they've been building for ages.
Then wonder why they'll need to be bailed out. Again.

What happened to innovation in the US ?

We'll have those 60+ mpg cars in Europe.

Those were race cars.
Normal driving and operating conditions no longer apply when racing.



Make it a user friendly design, and it won't be an issue.

Most people won't want to remove a headlight bulb either.
I replace both of mine in under 5 minutes.
I've heard a story about a non-Volvo garage taking an hour to do just one though, claiming "The other side would be even more difficult !"
(Both sides are identical.)

The best auto technology is developed in racing. Normal driving and operating conditions are amplified in racing, especially rally, so things that work on the stages should be adaptable to "real life". It's no wonder why Subaru has had so much success in the AWD market. It's also the reason Saab became what it was in the 50's-70's. Some people in the early 70's would have said turbochargers had no place in street cars.

I agree, but you know how things tend to go.

Most headlights are symmetrical but things such as batteries get in the way and restrict access ;) I would consider the battery side more difficult. Also, headlight bulbs don't need to be changed on the spot like tires do.

Another good reason to abandon GM altogether.

So there's no market for rear wheel skirts? Nobody's interested in them? No-one at all?

Then why the h*ll are so many people taking pictures of my car?
Two or three were surprised that the skirts aren't OEM.
And when people find out why I made them, they always ask: "Then why aren't they standard?"

Ah, well, but I live in a backward country...

Ummmm... Rear Fender Skirt - Insight Central: Honda Insight Forum

What Welburne said was accurate.

They did it more to make a statement than anything. Why doesn't the new Insight have skirts?

Yah I'm sure it was his decision and his alone. :rolleyes:

There are bigger fish to fry.

Loremo (no skirts) at .20 Cd is better than Insight with (.25 or .26).

Skirts are anything but new. If someone doesn't like them it's because the pros/cons didn't come out in the skirts' favor. There is a base of experience.

Focus groups can't find their *** with both hands.

They are consistently at or near the top in sales. Here's but one link: CleanMPG Forums - GM August Sales Up 18% Profitability is another matter.

Lawyers and politicians with too many restrictions; mgmt execs with no vision and failure to take the appropriate risks. The guys down in the trenches DO have innovative ideas...

We can blame the lawyers, politicians, and execs for that, AND the consumers too, who have proven extremely fickle and haven't provided the mfgs with a consistent market demand for economy.

Re: skirts off: Skirts- as we know them- very much impede checking and airing tires. That can be overcome... but it hasn't.

You have some pretty weird priorities. :rolleyes:

Nobody caught my rationale re: narrowed rear tracks eh? Ignore it at your peril... It's true and it's on the mark.

Anything out of the norm brings the cameras out.

All that said:

I personally am not scared of skirts for the reasons listed in my earlier post, but having ENGINEERED for an OEM before, I'm well aware of having to design for THE LOWEST COMMON DENOMINATOR.

Tell ya what guys: Go ahead and give all your allegiance and support to the car companies that sell cars with skirts. Do it.

I haven't mathed it out but I'd wager one skirt incident i.e. falling off would cost enough to repair to more than negate any fuel savings over it's entire lifespan.

Fuel saving "lifespan" is no issue anywhere else when it comes to fuel saving. OEMs install DRL led lights to their headlamps. When one of those leds gets failure you have to change whole headlamp which is pretty expensive...

Anyway that was their current opinion. That will change when the time is right. Who has the balls to start making a serial production car with proper fender skirts will propably have a little egde.

Like people said if you want them there are aftermarkets that can and will handle the need. I will desing and build fenderskirts to any car if they are willing to buy them at proper price. Price will be 15 times more expensive than what oems would have to pay from them.

I think my lupo has now some pretty sweet looking fender skirts at the moment. I have a idea how to make the installation very simple, but again if you cannot find a investor who is willing to put their money on the table. Ideas will stay inside my head.

Dunno.
It's also a lot less efficient.
So is the CR-Z.

Dunno over there, but neither are selling well in Belgium.
The only CR-Z I've seen driving around so far was a test car at the dealer's.
I've seen more Bentleys than that :cool:

New insights are few and far between.

Is that for the original or the revised design ?
No production values though, as there's no production car.
If ever, as it's been eerily quiet around Loremo.
(I've been on their waiting list from 2005. The mail server still worked last July, sending out birthday wishes to its subscribers.)

It'd have been even better with skirts.

And a large contributor to the very mediocre average MPG on new cars in the US.

Innovations like the Michelin Tweel will make that unnecessary.
Won't be for tomorrow though, but it's coming.

There's plenty of cars with a slightly narrower rear track.
Not as much as would be needed for skirts though.

If everybody kept designing for that, we'd still be driving Flintstone-mobiles.

Not so. With EFI, a/ts, traction control, stability control, ABS, airbags, etc., and etc., one practically needs no skill at all to drive.

The mechanix mags have featured airless tires that were "right around the corner" for 80 years now. I won't be holding my breath for that one.

The large contributer to lousy fe isn't GM, it's the fact that the customers are choosing GM full size pickups and SUVS instead of compacts.

There is no production Loremo but there is a physical one that presumably has been tunnel tested.