Everyone on staff who drove the Silverado HDs immediately noticed what the engineers changed for 2011 -- as well as what they left alone. Chevrolet developed new fully boxed frames for the HDs, plus there are more crossmembers, and the front frame segments are hydroformed. As a result, bending, torsional, and beaming stiffness were dramatically increased; vibrations were reduced; and ride and handling were improved.
GM totally redesigned the independent front suspension, which also improves ride and handling and the front axle's weight rating, reduces noise, and allows for a snowplow attachment on 4WD models. With the new frames, nicely weighted steering, and new suspension tuning, the Chevrolets drive like much smaller trucks, even though they are basically the same size as Ford's Super Duty models. And they had the best ride comfort of the group, bar none.
GM also attended to the engine bay. New regulations required a reduction in diesel emissions, so GM integrated a selective catalytic reduction aftertreatment system, which squirts a urea/distilled water mix into the exhaust. The chemical reactions that occur there reduce NOx emissions by 63 percent over those of the 2010 Duramax (yes, doubters, the big, honkin' diesel is green!). GM also increased the 6.6-liter's horsepower to 397 and torque to 765, up by 32 and 105, respectively. Chevrolet essentially left its 6.0-liter Vortec V-8 alone, with its 360 horsepower and 380 pound-feet of torque.
However, the heavy-duty market is fiercely competitive, and even though the Silverado HD's diesel horsepower and torque numbers initially beat those of the new Ford Super Duty -- at 390 horses and 735 pound-feet -- just after GM released its power numbers, Ford responded with a software upgrade that brought its Power Stroke's output to a nice, even 400 horsepower and 800 pound-feet. And Ford now has best-in-class towing capacity. On paper, that decision made it look as if the Ford would be crowned king of the segment. We could pack up our gear and go home, right?