Earlier this week, the Swedish consumer magazine Teknikens Värld revealed that the Jeep Grand Cherokee nearly rolled over in their "moose test." While the magazine and automaker debate the testing particulars, with the latter involved in some damage control public relations, our engineers explore what this means for U.S. consumers.
The European moose test is a double lane change maneuver that simulates an emergency situation, requiring a quick steer to avoid an obstacle and then turning back into the travel lane to avoid an oncoming vehicle. According to Teknikens Värld, in every run performed with the Grand Cherokee, the vehicle either went up onto two wheels or debeaded tires (separating the rubber from the wheels) thereby posing the risk of a tripped rollover.
Chrysler's corporate press release states that the test is "invalid" because the vehicle was overloaded beyond its stated load capacity. A separate blog on a Chrysler website says it was overloaded by 110 pounds.
After the results were revealed, Chrysler engineers met with the magazine, providing three Grand Cherokees for a re-test. For subsequent tests, the Chrysler engineers witnessed that vehicle was properly loaded. While no other instances of two-wheel lift occurred, the magazine states that the tires were also debeaded in these runs. (Read: "Jeep Grand Cherokee's moose test failure—truth and facts.")
Consumer Reports tests the emergency handling of all vehicles in our own double lane change maneuver, which is similar in concept. Our test is less severe than the "moose test" with more distance between the entry cones and the gate cones, typically resulting in less steering input. Plus, we test the vehicle loaded with only a driver and a full fuel tank.
We have tested two 2011 Grand Cherokees, a Laredo with the V6 and a Limited with the V8. Both had 18-inch wheels and tires. During our initial tests, the Laredo V6 hopped and skipped sideways. While it did not debead tires or go up on two wheels, this behavior did impair driver confidence and affected the speed at which we could negotiate the course. The Limited V8 did not exhibit this behavior.
After that test, Chrysler recalibrated the stability control and issued a software update in January 2011. The software changes eliminated the problems we encountered and increased the speed and confidence through the course. This update was flashed into existing vehicles and incorporated into later-production Grand Cherokees.
Our experience with the Jeep, as well as the hundreds of other SUVs we've tested, shows that the way the vehicle is equipped can have a considerable effect on its performance in this test. Tire specifications, suspension calibrations, and weight balance all play a role here. The Grand Cherokee tested by Teknikens Värld was a top-level Overland 3.0 CRD V6 (diesel) model with 20-inch tires that comes with adjustable suspension. (The diesel is not currently sold in the U.S. market; engine selection will affect weight balance.)
Loading is a point of contention in this moose test since it was run with five occupants on board and sandbags in the cargo area. While Chrysler states that the Jeep was overloaded by 110 pounds—about 7-10 percent of the payload rating—Teknikens Värld states the vehicle was weighted appropriately according to the Swedish registration certificate. Individual vehicles can have different payload ratings because of variances in optional equipment, which may be different from weights listed in compliance paperwork. Regardless, it could be argued that overloading it by 110 pounds falls within the realm of foreseeable misuse by a consumer and such a variance should be accounted for in vehicle development.
So what should a consumer here in North America take away from this test?
We hope that Chrysler and Teknikens Värld get to the bottom of why the Grand Cherokee failed the moose test, because no modern vehicle should perform as shown in the magazine's video.
Related:
Consumer Reports: Jeep Grand Cherokee road test
Update: Chrysler fixes 2011 Jeep Grand Cherokee handling problem
—Tom Mutchler
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