The Lug Nut Rule Explained

There is an old adage, “He, who has the most lug nuts, wins.”

In 2002, the National Academy of Sciences released a report that concluded that “the downweighting and downsizing that occurred in the late 1970s and early 1980s, some of which was due to CAFE standards, probably resulted in an additional 1,300 to 2,600 traffic fatalities in 1993.” CAFE’s goal was to require automobile companies to meet fuel mileage standards averaged over the entire fleet of cars sold, under the assumption that the United States would benefit if drivers used (and therefore imported) less oil. Between 1990 and 1996, the statutory mandate set the level of average fuel efficiency to a minimum of 27.5 miles per gallon. Of course, the laws of physics involving inertia, rolling resistance, and wind resistance dictate that it’s far easier to get high mileage from small cars than it is from large ones.

Smaller, lighter cars don’t need the high horsepower engines of larger, heavier vehicles, plus smaller cars usually sport smaller rims. The wheel assemblies on smaller cars therefore do not need to handle the high torque generated by large engines. Manufacturers, trying to make smaller cars lighter and cheaper, use the lower torque requirements to justify using fewer or smaller bolts. A typical two-ton vehicle can have ten or more lug nuts, a three-quarter-ton pickup might have eight, a half-ton pickup or SUV usually has six lug nuts, and most passengers cars have four or five.

So, using the lug nut test to determine who wins means that a 1,830-pound Renault LeCar (3 lug nuts per wheel) loses to a 2,300-pound Honda Accord (4 lug nuts), an Accord loses to a 3,300-pound Toyota Camry (5 lug nuts), a Camry loses to a 3,600-pound Saturn Vue (6 lug nuts), a Vue loses to a 5,200-pound Chevy Suburban 2500, 6,400-pound Hummer H2, or 9,200-pound Ford Excursion (all of which have 8 lug nuts standard), and just about everyone loses to a big rig or passenger bus (at least 10 lug nuts per wheel).

Most pedestrians don’t carry lug nuts, so they lose by default.

An Exception to the Rule

Photo @ Dr. Ing. h.c. F. Porsche AG

The $440,000, 3,043-pound 2005 Porsche Carrera GT is perhaps one of the few exceptions to the rule. With no true lug nuts at all (only a single titanium lug bolt per wheel), the sports car weighs about 700 pounds more than my 1996 Saturn SL2 with itsĀ four lug nuts per wheel.

While I may lose any real collision with the heavier GT at least I can rest in peace knowing the owner will be paying for it for a long time — just one headlight assembly on the carbon-fiber-reinforced-plastic body of the GT probably costs more than my entire car is worth, and the owner will have to ship the GT back to the factory in Leipzig, Germany, to get it fixed.

Walk carefully, and carry a set of lug nuts in your pocket!

3 Responses to “The Lug Nut Rule Explained”

  1. richard

    I’m hoping so! Now that I’ve moved away from MovableType onto WordPress, I should be able to concentrate more on actually writing blogs instead of wasting that time removing comment spam.

  2. Ross

    There is another school of thought on the “Lug Nut Rule”. It serves as a warning to arrogant cyclists who believe they are somehow superior to motorists because of certain legal protections they enjoy. It states that: “Any time a bicylce or motorcycle tangles with a car or truck, leagal matters of right-of-way notwithstanding, the vehicle bearing the lug nuts will win the fight.” I ride a bicycle and I live by this simple, undeniable rule. Hard to feel superior with a broken back.


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