Reports Tow Tests and Ranks Half Ton and Heavy Duty Pickups.
Consumer Reports has just released its latest rankings for full size pickup trucks and the results prove one thing – pickups are a pain in the arse to compare.
I've got a lot of respect for Consumer Reports. Some folks say CR has a bias favoring import vehicles, but there’s no reason to believe the hype. What’s in it for them? They don’t receive a penny in advertising from the automakers and they purchase all of their test vehicles directly from the same place you or I would, at a dealer. And CR examines all the vehicles it tests at its own world class facility in Connecticut, where cars and trucks are subjected to 50 different performance tests with the best vehicle instrumentation money can buy.
But some may question more than usual this year’s testing approach for half-ton pickups, which scores the new 2007 Toyota Tundra ahead of the new 2007 Chevrolet Silverado 1500, and also ranks the latest Dodge Ram 1500 and Ford F-150 pickups.
Consumer Reports has placed a lot of editorial emphasis on towing capability, and rightly so given this year's advertising hype about which light duty pickup can tow the most. In the absence of a standardized, industry-accepted approach to testing towing capability - which exist for measuring engine power and fuel economy - manufacturers have been free to throw out any big number they want with a lot of small text underneath to explain in exactly what circumstance and truck configuration that number might be possible.
So, CR hooked up each of the trucks to a 7,400-pound trailer to measure their 0 to 60-mph performance. Why 7,400-pounds? Because the Chevrolet Silverado, configured with a 315-hp / 338 pound-feet of torque 5.3-liter V8 and a 3.73 rear axle, was rated at ‘only’ 7,500-pounds towing capacity.
Hold on tight because here’s where it gets complex.
If you’re going to test comparable pickups, especially towing, it’s not enough to line up trucks with similar engines. You also need to gather trucks with similar cabs (regular, extended, crew), bed lengths (short, long), and drivelines (2WD, 4WD, AWD). And you also need similar rear axles, which are, perhaps, the most difficult component to match between trucks.
Rear axles are rated with a number to describe how many rotations the driveshaft must make to turn the rear axle (and rear wheels) once. For example, the Silverado tested by CR had a 3.73 ratio, which means its rear axle turns once every 3.73 driveshaft rotations.
The rear axle ratio can make a big difference in towing performance. The higher the ratio, the faster the driveshaft turns and the sooner the driveshaft can transfer peak horsepower and torque from the engine to the rear wheels. The result, generally, is faster acceleration and higher towing capacity than a rear axle with a lower ratio.
As an example, if you take two 5.3-liter V8 crew cab short box 4WD Chevrolet Silverados - one with a 3.73 rear axle and the other with a 4.10 rear axle, not only will the 4.10 pickup accelerate faster than the 3.73 truck, but it can also tow 1,000-pounds (13%) more.
The tradeoff for a higher axle ratio, though, is usually lower fuel economy, because an engine that's working harder is also burning fuel faster. It's one of the most difficult purchase decisions a buyer might make after model and engine selection - compromising between rear axle performance and fuel economy for optimal towing.