The new chassis is stronger, stiffer and fully boxed; many good things flow from there. If the last Suburban you drove (or owned, or still own) felt hinged in the middle and rode hummocks like a porpoise, the new and improved 2007 will dazzle you. The ride is steady and comfortable, and the handling is tighter and more precise. We drove our Suburban hard, from New York City north on the rough I-95 to Providence, R.I., and then back down over some twisty thruways that only a sports car, coupe or sedan could love, onto the tortuous Henry Hudson Parkway and finally into the depths of the potholes of the Big Apple. The Suburban was a dream.

Until it was time to park it. Then, in the city, it was simply a matter of finding an outside lot that could take all of its 18.5 feet. You can pretty much forget about parallel parking unless you find two spaces, even with the rearview monitor and backup beeper.

The new boxed frame is 49 percent stiffer and 35 percent more resistant to twisting. The front track has been widened by three inches, and the rear by one inch. The suspension has been totally redesigned, using coil-over-shock absorbers in front and a beefed-up five-link rear suspension around a solid rear axle (better for towing) in the rear. A power rack-and-pinion steering system is used, for the first time.

The upgraded suspension and steering have moved the Suburban into new territory: quality ride and handling. This results in safety through accident avoidance. The new frame also increases structural safety, as the forward section with hydroformed rails improves crushability.

Our Suburban was not equipped with AutoRide, the optional suspension that electronically adjusts to the road, as read by sensors. It reduces body lean in corners and nose dive under hard braking. If you drive your Suburban harder than we drove ours, or if you tow a lot, AutoRide might be considered.

The new, all-aluminum 5.3-liter Vortec V8 makes 310 horsepower and 335 pound-feet of torque (the other 5.3 liter, with an iron block and aluminum heads, makes 320 hp and 340 lb-ft). Either engine can run on regular unleaded fuel or cleaner-burning E85 (85 percent ethanol and 15 percent gasoline). Ours was four-wheel drive, EPA rated at 15 city and 20 highway miles per gallon. We averaged just over 15 miles per gallon on our lead-footed four-hour run on winding and rolling thruways.

If you need more power for towing, which is what the Suburban excels at, you can get the 2500 (three-quarter ton) chassis and/or the 6.0-liter engine, making 360 horsepower and 380 pound-feet of torque, still using regular unleaded fuel. With 4WD, it's rated to tow 9400 pounds, compared to the 1500's 8000 pounds.

We were pleased with the acceleration, especially considering the vehicle weighs nearly three tons (5745 pounds), and we were happy with the powerful sound of the engine under full throttle. This is a V8 Chevy, after all. The four-speed automatic transmission is smooth, but we wonder what would happen to the fuel mileage if there were a fifth and taller gear, like most of the competition has. Fourth gear is a fairly tall overdrive with a ratio of 0.70:1, and the final drive ratio is 3.73:1 (4.10:1 is optional, for better acceleration and towing), so a fifth gear would seem called for, although we can't say we missed it. The big torque of this engine overcomes a lot.

The 5.3-liter engine uses GM's Active Fuel Management, which shuts down four of the eight cylinders when they're not needed. But the fly in the AFM ointment is that they're needed virtually all of the time except when the throttle is totally backed off, a time when the engine isn't sucking up gas anyhow.

The new brakes with vented rotors are bigger (13 inches in front and 13.5 inches rear) and the dual piston calipers are stiffer. It's an important safety consideration, especially when towing. The brakes worked well and were easy to modulate, something lacking in the Suburbans of two generations back.