LongTimeListener
Well-Known Member
- Thread starter
- #1
Great article.
https://www.roadandtrack.com/car-culture/a29339668/how-truck-tow-rating-is-calculated/
How Your Truck Got Its Maximum Tow Rating
Road & Track contributor Jason Fenske visited Fiat Chrysler's Chelsea Proving Grounds in Michigan to see what goes into the set of tests known as SAE J2807, the certification process for vehicle tow rating. The truck used in Fenske's demonstration is a new Ram Heavy Duty, complete with a dually rear end and a 6.7-liter turbo-diesel Cummins straight-six making 1000 lb-ft of torque. For each test, the truck must be towing the maximum load recommended by the manufacturer, meaning this Ram is pulling just under 40,000 pounds.
The acceleration test requires single-wheel trucks to do 0-30 mph in 12 seconds, 0-60 mph in 30 seconds, and 40-60 mph in 18 seconds; those times increase to 14, 35, and 21 seconds, respectively, for dually models. Those times might sound like an eternity in the car world, but for a vehicle pulling the equivalent of 16 new Miatas, it's not bad. The truck must be able to brake from 20 mph to zero in 45 feet with trailer brakes, or 80 feet without.
In terms of handling, the truck needs to be able to maintain understeer as it accelerates on a circular skid pad from 0.1 g to 0.3 g of lateral acceleration. This ensures the truck won't lose control of its rear end (and therefore the trailer) during hard cornering scenarios. In a quick direction-change sway test, the trailer must remain stable and secure without excessive oscillation.
The final test is called the Highway Grade / Davis Dam test, which wasn't performed in Fenske's video. It requires that the truck be able to tow its maximum trailer weight up a specific 11.4-mile uphill stretch of road in Arizona. For this test to be run correctly, it must be at least 100 degrees Fahrenheit outside, and the air conditioning must be on its maximum setting using outside air. The truck must maintain a minimum speed of 40 mph (35 mph for a dually), and it can't throw any error codes or burn any fluids during the test.
https://www.roadandtrack.com/car-culture/a29339668/how-truck-tow-rating-is-calculated/
How Your Truck Got Its Maximum Tow Rating
Road & Track contributor Jason Fenske visited Fiat Chrysler's Chelsea Proving Grounds in Michigan to see what goes into the set of tests known as SAE J2807, the certification process for vehicle tow rating. The truck used in Fenske's demonstration is a new Ram Heavy Duty, complete with a dually rear end and a 6.7-liter turbo-diesel Cummins straight-six making 1000 lb-ft of torque. For each test, the truck must be towing the maximum load recommended by the manufacturer, meaning this Ram is pulling just under 40,000 pounds.
The acceleration test requires single-wheel trucks to do 0-30 mph in 12 seconds, 0-60 mph in 30 seconds, and 40-60 mph in 18 seconds; those times increase to 14, 35, and 21 seconds, respectively, for dually models. Those times might sound like an eternity in the car world, but for a vehicle pulling the equivalent of 16 new Miatas, it's not bad. The truck must be able to brake from 20 mph to zero in 45 feet with trailer brakes, or 80 feet without.
In terms of handling, the truck needs to be able to maintain understeer as it accelerates on a circular skid pad from 0.1 g to 0.3 g of lateral acceleration. This ensures the truck won't lose control of its rear end (and therefore the trailer) during hard cornering scenarios. In a quick direction-change sway test, the trailer must remain stable and secure without excessive oscillation.
The final test is called the Highway Grade / Davis Dam test, which wasn't performed in Fenske's video. It requires that the truck be able to tow its maximum trailer weight up a specific 11.4-mile uphill stretch of road in Arizona. For this test to be run correctly, it must be at least 100 degrees Fahrenheit outside, and the air conditioning must be on its maximum setting using outside air. The truck must maintain a minimum speed of 40 mph (35 mph for a dually), and it can't throw any error codes or burn any fluids during the test.
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