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The ability of a vehicle to pull a load is not a function of horsepower, like you see on TV ads, iit's a function of torque to gross weight. The older trucks I pulled triples and supertrains with had about 1250 ft/lbs of torque pulling 120,000 pounds of crude or refined products. That works out to 96 pounds of load per unit of torque. Modern heavy big rigs gross 80,000 pounds and run about 50 to 60 pounds per unit of torque.
The W451 Smart FourTwo, pulling a half ton, tips the scales at 3000 lbs. With 68 ft/lb of torque, that's 44 pounds of load per unit of torque - and why I can run in the truck lane on highway grades fully loaded with no problem, and even pass 'em if I want. But like I said, I baby my Smart. If I'm in a hurry, I leave earlier. That's all.
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Ptero
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