Colorado and Canyon Off Road Tests

[Drag]

OK, so these aren't HUMMER vehicles per se, and perhaps this article should go into another section, but I think that the H3 is based on this same platform, and so it may be interesting to see what the platform is capable of.

No Poseurs: We take GM’s new small trucks on a true off-road adventure


By LARRY EDSALL


The GMC Canyon
WITH FEW EXCEPTIONS, an invitation from an automaker to “come drive our newest 4x4” usually trans-lates into a cruise along some gravel road, with perhaps a quick detour to climb a hill steep and rocky enough that you might actually engage four-wheel drive, then crest the hill’s summit and ease on down the other side.

So we were skeptical when General Motors said it had set up a daylong off-road exercise to show the abilities of its new Chevrolet Colorado and GMC Canyon midsize pickup trucks.

Our skepticism waned soon after we punched the 4HI button only a few miles into the Telegraph Canyon Trail, evaporated as we carefully rock-climbed along the Martinez Mountain Trail, and turned to awe in Box Canyon, a steep-walled slit through the mountains some 60 miles southeast of downtown Phoenix.

Backcountry Adventures: Arizona rates the Martinez mine route a 4 and the Telegraph Trail and Box Canyon each a 5 on a scale that says 6-rated trails “are for experienced four-wheel drivers only,” and are “potentially dangerous.” Not that a 4 or 5 is a simple matter. Backcountry suggests that while a “stock SUV” might suffice for a 4, for a 5 you’ll need a high-clearance 4wd vehicle and even then some sections “may be impassable for inexperienced drivers.”

Indeed, there were several places where drivers needed a spotter’s hand signals to assure proper tire placement for traversing boulders that blocked the way.

The 4wd trucks we drove were stock GMT 355s, and each was equipped with the new 200-hp Vortec 3500 inline five-cylinder engine and the Z71 off-road suspension that includes 40-mm monotube shocks front and rear, urethane (instead of rubber) rear jounce bumpers, a G80 “Eaton Locker” differential, General AmeriTrac 15-inch TR off-road tires, plus skid plates and front recovery hooks.

The Canyon SLE crew cab (3.42 rear axle) and the Colorado standard cab (3.73 axle) each had GM’s four-speed automatic transmission while the Colorado extended cab had an Aisin five-speed manual transmission and 4.10 gear.

The most obvious dynamic difference among the three vehicles was in engine braking in steep descents, where the 4.10 and manual provided the most braking and where the 3.73 offered noticeably more control for the driver than the 3.42.

The inline-five, with 225 lb-ft of torque, handled even the steepest of hills and got us over some substantial boulders. But the most obvious dynamic similarity among the three vehicles was the way the suspension kept the tires in constant contact with the uneven trail, whether we were going through washes, ascending hills, negotiating narrow ridges or picking our way through the big rocks. We experienced none of the typical pickup truck rear-end bounce, and only in extremely rough sections was there even much head tossing inside the trucks’ passenger compartments.

GM claims the chassis is 250 percent torsionally stiffer than the predecessor GM S10/Sonoma. “The chassis is so stiff, it allowed us to tune the suspension to do what it’s supposed to do, to control the body and not just shake,” one GM engineer explained from the passenger seat as we picked our way along the trails.

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Nobody expects the Spanish Inquisition!!