The linkages performing so admirably beneath a GPX include front struts with coil springs, performance-tuned Carbon monotube
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| The upgraded 4-wheel antilock disc brakes on the GXP repeatedly pulled in quick, easily controlled, fade-free stops. (Photo: Rob Rothwell, Canadian Auto Press) |
dampers and an anti-roll bar, plus rear semi-trailing arms managed by coil springs, complemented by an anti-roll bar and an automatic self-leveling system. In addition to competent handling characteristics, the folks at Pontiac ensured that excessive road noise would be off-limits in a Bonneville. Five layers of insulating materials and 22-noise blockers are used to prevent noise from intruding into the cabin, although wind-rush becomes evident at highway speeds - perhaps accentuated by the quiet of everything else. With a curb weight of 1,719 kilos (3,790 lbs) the GXP requires strong brakes to be a contender in the performance car category, and it has them in the way of 14-inch rotors up front and 13-inch rotors working the rear. The upgraded 4-wheel antilock disc brakes on the GXP repeatedly pulled in quick, easily controlled, fade-free stops. Pedal actuation was good, holding no surprises. It seemed the only encumbrance to shorter stops was the grip, or lack thereof, delivered by the P235/50R18 Goodyear Eagle mud and snow radials.
Widening the GXP's vehicle control safety margin is GM's StabiliTrak traction and yaw control technology, which responds in the thousandths of a second when a lateral skid is detected. When such forces of nature take hold,
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| The Bonneville earned the highest rating possible from the U.S. National Traffic Safety Administration for rollover resistance. (Photo: Rob Rothwell, Canadian Auto Press) |
StabiliTrak applies wheel specific braking to return the GXP to the driver's intended path. Should Mother Nature's forces dominate man's technology, the Bonneville is highly resistant to rollovers. It has earned the highest rating possible from the U.S. National Traffic Safety Administration in this category. But in life accidents are not always avoidable. Fortunately the GXP is equipped with dual frontal airbags and seat-mounted, side- impact airbags, plus OnStar in-vehicle communication and assistance is also standard equipment. The extra protection provided by side-impact airbags and OnStar system is available as an option on SE and SLE Bonnevilles.
