C&D Tests: Explorer Survives Blowouts
ANN ARBOR, Mich.--What happens when a left rear tire on a 1994 Explorer blows on a paved straightaway at 70 mph? Surprisingly, not much, said Csaba Csere , editor-in-chief at Car and Driver magazine.
Id trust my own mother driving in similar circumstances, said Csere following a series of road tests that he and a team from Car and Driver magazine conducted on Oct. 23 and 26. Results of the tests, conducted at Milan Dragway just south of Car and Drivers Ann Arbor headquarters, revealed that, during a tire failure, the Explorer, like other modern vehicles in our experience, remains stable and easy to control, said Csere.
Nothing happened to explain why an Explorer, similarly equipped and under the same conditions, might veer from the paved roadway. And, unless the vehicle leaves the pavement, a rollover is extremely unlikely.
Csere speculated that some drivers panic or are startled by the sound of a tire disintegrating or blowing out, then jerk the steering wheel or slam on their brakes. Even so, when Technical Editor Larry Webster, who drove the test Explorer, fully applied the brakes during one blowout test at 70 mph, he had no trouble controlling the vehicle.
Car and Driver bought the used 1994 four-door, 4WD Explorer Oct. 20 at an independent, used-car dealership in Redford Township, Mich., a suburb of Detroit. The vehicle was equipped with Goodyear Wrangler RT/S tires (installed during the Firestone recall) and the odometer read 37,137 miles (a figure Csere suspects is 100,000 miles too low).
Car and Driver had a roll cage and competition seat belts installed to protect the driver, but nothing else mechanically was done to prepare the vehicle for the tests. To record results, two video cameras were mounted: One inside the vehicle, trained on the driver, and one outside the vehicle, aimed at the left rear tire.
The blowout was achieved by fitting a modified wheel with a special valve that would deflate the tire in one-third of a second. This device was triggered remotely via hand-held transmitter. The modified wheel was fitted to the left rear tire of the Explorer because that position was the one most commonly cited in the Firestone blowout complaints.
With Webster at the wheel, Csere triggered the blowout once the vehicle came up to speed. Since we were able to perform repeated blow outs, we began our tests at 30 mph and worked out way up to 70 mph in 10-mph increments, explained Csere. Larry did not know exactly when the blow out would occur.
In every case, even at 70 mph, the Explorers performance was remarkably undramatic. When the blowout occurred, the left rear of the vehicle settled down, but the Explorer continued straight ahead. I even kept my hands off the steering wheel during one blowout at 70 mph, and the Explorer continued straight. Not until I applied the brakes, which pulled to the left, was I forced to put a hand on the wheel and correct the Explorers path, explained Webster.
Only after applying the brakes as hard as possible after a 70-mph blowout, did the Explorer wiggle at all. Even then it would have easily stayed within the confines of a normal traffic lane, said Csere.
Based on these results, Csere offers the following advice to drivers of any vehicle who suspect that they are experiencing a tire problem:
-- Dont panic; modern vehicles tend to remain stable during tire failures.
-- Keep the vehicle going straight and on the pavement. The chance of rolling over is minimal unless you leave the roadway.
-- Unless theres an immediate obstruction in your path, dont be in a big hurry to stop. The additional drag of the deflated tire will slow your vehicle down by itself pretty rapidly. Ease your foot off the accelerator and apply the brakes gently to come to a full stop at the side of the road.
If you follow these guidelines, you have an excellent chance of making sure that your tire failure remains an inconvenience rather than turning into a tragedy, said Csere.
Csere holds a degree in mechanical engineering from the Massachusetts Institute of Technology. He joined Car and Driver in 1980, has held positions of technical editor and technical director, and has performed instrumented tests on more than 800 cars. Previously, he worked on fuel injection systems at Fords Advanced Engine engineering office. Webster is a graduate of Lehigh University where he majored in engineering, and he joined Car and Driver in 1994. He is one of the magazines main road test drivers.
Coverage of the tests and details of results will air on the Car and Driver Television show on TNN in November (check newspaper listings for date and time) and will soon be posted to the Car and Driver Web site (www.caranddriver.com). Results also will be featured in the January 2001 issue, on newsstands Dec. 10.
Car and Driver magazine, headquartered in Ann Arbor, Mich., is the worlds largest circulation automotive magazine and the premier source of information for automobile enthusiasts. Content includes everything from new car previews, road tests and features to industry news and automotive humor. (The editor-in-chiefs name is pronounced Chubba Chedda.)