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[Chance]

Originally Posted by rynosback

Why do you say that they are held to a higher standard? The whole goal of the SAE J2806 is that you could really compare numbers as they all test them the same way.

Not sure if this is the latest, but seems to be tougher on SRW trucks on acceleration and hill climbing.

SAE J2807 Tow Tests - The Standard

Originally Posted by TruckTrend

Flat-Out Acceleration

Three tests are used to determine if a truck/trailer combination has sufficient acceleration on flat sections of road. One is a test that measures the 0-to-30-mph time, with single-rear-wheel trucks needing to reach that speed in 12.0 seconds, while dual-rear-wheel models get 14.0 seconds. There is also a 0-to-60-mph acceleration test that allows SRW trucks 30.0 seconds to reach that highway speed while DRW models get 35.0 seconds. To measure passing capability, the 40-to-60-mph time of single-rear-wheel trucks must be 18.0 seconds or less, and dual-rear-wheel trucks are allowed up to 21.0 seconds.

Making the Grade

To simulate some of the toughest conditions a truck and trailer combination will face, the J2807 “Highway Gradeability” tests take place on a well-known stretch of Arizona highway, the 11.4-mile-long Davis Dam Grade. If trucks are not tested on this specific stretch of steep road, they can be run in a simulation using a “climactic” wind tunnel. Ambient temperature plays a significant role in this test with a minimum temperature of 100 degrees required at the base of the grade. In addition to a hot climate outside the truck, the test requires the air conditioning system to be set at maximum cold, with outside air selected (not recirculating) and the fan running at full blower speed.

Once those criteria are met, the evaluation can begin on the famous stretch of SR 68 between Bullhead City and Golden Valley, Arizona. To pass this test, a truck-and-trailer combination must be able to drive at 40 mph (35 mph for dualies) and never drop below that speed until the end of the test segment at the peak of Union Pass. Testdrivers are allowed to go faster than the minimum speed requirement in the sections of the grade where posted speed limits are 55 mph and 65 mph, but there are other requirements the vehicle must still meet. Under “drivetrain system performance,” the J2807 standard requires there be no component failures, along with no “check engine” lights or any other alerts or warnings for the driver. The “cooling system performance” requirement also requires zero part failures, no error codes, no driver warnings of any other kind, and no loss of coolant fluid during the test.