|Larry Vellequette covers Chrysler Group for Automotive News|
If the English-speaking world changed the name of the common cold to "fatal sniffles," the ubiquitous ailment would sure get a lot more attention from drug companies and the media -- but the symptoms would remain.
The common cold is an effect of our body's design, the cost of living in a world filled with viruses and having a nose.
Such is the case with the named-for-TV-news Jeep "death wobble," a condition inherent to any vehicle with straight front axles which has jumped back into the news.
To consumers whose videos showing the condition litter YouTube, the ill-named "death wobble" is a violent shaking of the steering wheel and front steering linkage at certain speeds. If a driver fails to react, it potentially could cause loss of control.
Two members of Congress -- one of a select few professions held in lower regard by the public than journalists and car salespeople -- have now taken up the cause of the "death wobble." They've asked Chrysler to alert owners of straight-axle Jeeps, like the Wrangler and 1984-2001 Cherokee, of the condition and suggest methods to repair and prevent the problem.
But to engineers, the potential for "wobble" is an inherent design limitation of all vehicles with straight front axles and transverse steering -- designed for rugged applications -- and is related to the interaction between its steering geometry and suspension. Engineers can work to minimize the effects of the wobble in solid-axle vehicles, but they can never eliminate it entirely.
The Wrangler's solid front axle, track bar and drag-link steering system is an integral part of what gives the 4x4 its unmatched off-road chops -- in short, it's what makes the Wrangler a Wrangler. For visual proof of what I'm talking about, just search for photos of off-road enthusiasts rock climbing and see the ridiculous angles that even a stock Wrangler's tires can move relative to its body.
But the off-road functionality provided by such systems comes at a price: on roadways at certain speeds, the front wheels can develop a harmonic resonance with the tie rod, which connects the front wheels together. It can make a kind of feedback loop of shaking that grows upon itself until it's interrupted, like a microphone that's too close to its speaker.
This is especially true if the vehicle isn't properly maintained, if the tires have uneven tread wear, if it's out of alignment, or if any of the suspension components are worn or broken.
Engineers can work to minimize the effects of the wobble in solid-axle vehicles, but they can never eliminate it entirely.
Concerns about "death wobble" may be the inevitable consequence of more consumers buying -- and perhaps Chrysler or dealers selling -- a vehicle like the Jeep Wrangler as though it were any other "put it in drive and forget it" sedan. It's not. It's a specialized vehicle designed for off-roading, which also happens to be able to provide a relatively comfortable ride as a daily driver.
I agree with the two member of Congress that more consumer education is needed, and that should start at the dealership with the sales process. Chrysler has broken its monthly sales records for the Wrangler in each of the last two months, and Wrangler sales are up 33 percent so far this year at 70,871 units.
Consumers don't seem concerned about the "death wobble" reports so far, but they do need to be educated what to expect.
If consumers know that this condition is less likely to occur with frequent tire rotations and regular maintenance, they are less likely to over-react when it does happen.
But I don't agree that Chrysler needs to change the design of the Wrangler, or abandon its coil-link suspension or transverse steering, just because consumers can't properly maintain their vehicles or drive within its capabilities.