We tied a two-ton boat to the back of each and headed up and down our test route's six-percent grade with the same cargo, full fuel tank, and weather, and in three acceleration trials--one roll-on and two standing start, uphill and level--the extra cogs gave the EL a 1.2- to 3.1-second advantage, and they both climbed to near 70 mph where the EL leveled off at 72 mph and the Sub at 69 mph. In ambient temperatures of 86 to 99 degrees F, we kept an eye on the gauges (we didn't want to cover our new Monterey--courtesy of Castaic Boat & Marine--in undercoating). The Ford coolant indicator never moved, though we've questioned them as nothing more than analog idiot lights before. The Suburban, which has superior numbered and fast-to-respond analog gauges plus a digital ATF display, raised coolant temp from 210 to 235*F and transmission from 190 to 221*F during tow climbing. All the revving caused by Chevy's four-speed generated heat and noise; The Ford was quieter except at wide-open throttle redline and ran much lower revs for the majority of the exercise.
Extra gears mean better mileage, too. The Motor Trend duo had the EL ahead 18.7 to 15.0 mpg compared with the 5.3-liter V-8 with Active Fuel Management. Our Chevy's 6.0-liter V-8 with cylinder deactivation, didn't surprise us either. Towing, the Ford covered the 84-mile loop at 11.3 mpg while the 6.0-liter Sub slurped along at 8.7; combine that roughly 30 percent advantage with a larger tank, and the Expedition's range is better by 100 miles per fill (on-board trip computers showed our empty EL was more efficient, but they were both off by 10 percent on the tow loop, so we're discounting those observations). Finally, the extra gears allowed the smaller displacement of the EL to provide better compression braking, limiting speed to 65 mph in fourth while the 300-odd-pound-lighter Chevy used third to hold 64 mph.
Either truck makes a suitable towing platform, though hardware may be optional, as the hitch/wiring and rear air suspension were on the EL. We parked, engine off, prior to loading the trailer, and each dropped about two inches; firing them up engaged air leveling, and they returned to standard ride height, the Suburban's hitch a good 2.5 inches further off the ground. Excepting the domed hood that costs some visibility, the view outward was better in the EL, especially to the rear and in rear-wipe coverage.
Round the Bend, the Block, the Rock
The Sub's new suspension calibration has removed a lot of the pitch and busy motion from the previous model, buttoned up but not strangled, and Autoride real-time damping makes it a bit sportier--it's not sporty, but is slightly better than the nanny-tethered EL in the slalom and tied in the figure eight (note the earlier Sub stopped and slalomed better on 17s). But with a trailer in tow, the Sub felt tightened further, resulting in a crisper ride and sharper pitching motions that jiggled rear-seat riders' bellies more. The Sub's steering is quicker and lighter than the EL's. Some felt it was too light at times, as it almost banged at the end of the rack maneuvering to full lock.
In contrast, the EL's rear air suspension (as opposed to air shocks), which is on a wider track than the front, has significantly less pogo-sticking, and slower but still accurate and nicely weighted steering made towing almost plush. Indeed, we likened the road isolation to a Sequoia or GX 470 and the towing ride to the difference between pulling a fifth wheel with a conventional hitch and an air hitch and got the impression it would take a lot more trailer to "drive" the Ford than the Chevy. With big discs and ABS all around, they stopped in the same 140 feet, an average number at best for passenger vehicles, but GM's brake feel has improved so much, neither truck had an obvious advantage.
An uninstrumented test was run over a loop, first with each vehicle empty and then with six more bodies spread across three rows to duplicate a load (about 70 percent of rated payload) and found manners didn't change much. The Suburban actually felt like it had more understeer, perhaps as rear shocks firmed up and the rear tires now carried the larger weight split--it's probably good that it's not as entertaining loaded as it is empty. The riders also noted that Chevy A/C gets cool air to the back sooner despite the Ford's venting quarter windows and that the Ford's third-row legroom was clearly superior while comfort ratings for the forward rows were debated until everyone agreed to disagree.