Sometimes you just need something big and strong, with genuine four-wheel drive, and you need it all in one vehicle.Something that will tow a sizable trailer and carry lots of people or haul a load of cargo over primitive roads is an indispensible tool for those who need it.That's the Suburban's mission.It has gotten more luxurious over the years, sometimes becoming a substitute for a large sedan.

The Suburban can handle 137 cubic feet of cargo, or up to nine passengers and 45 cubic feet of stuff, and myriad combinations in between.Two weight classes are offered, the normal 1500 and the heavy-duty 2500.

The Suburban's competitors in the full-size field are obvious.But, once you say Suburban, no other explanation is required.

For 2010 the changes are relatively few in number but significant just the same.All the engines offer Flex Fuel capability, meaning they will operate on gasoline or E85, which is 85-percent ethanol.There is a 6.0-liter with variable valve timing for the 2500 models.All radios have a USB port to accept compatible music devices.The four-wheel drive models have a standard single-speed transfer case, while a two-speed case is optional.There are a couple of new options packages, and the 1LT trim level now includes tri-zone climate control, a Bose nine-speaker premium audio system, power-adjustable pedals, remote start, rear park assist, and locking rear differential.The Z71 Off-Road suspension is available on the 1LT trim level.

Every 1500 comes standard with a 5.3-liter V8 engine of 310 horsepower, 335 pound-feet of torque and a six-speed automatic transmission.The engines in 1500 models with two-wheel drive have an iron block and those in four-wheel drive models have an aluminum block; both versions have aluminum heads.The 2500 has a 6.0-liter V8 with aluminum block and heads, rated at 352 horsepower and 382 pound-feet of torque, and also with a six-speed automatic.All engines are E85-compatible, which means they will run on 85-percent ethanol fuel, and all have Active Fuel Management (AFM) which switches off half the cylinders when the additional power or idle smoothness isn't needed.EPA ratings for 1500 two-wheel-drive Suburbans are 15 mpg City/21 mpg Highway on gasoline and 11/16 mpg on E85.

The 2500 heavier-duty Suburban has different steering gear, brake parts, suspension, alternator, wheels, tires, axles and fuel tank than the 1500 series.The primary reason for selecting the 2500 over the 1500 is for its greater towing capacity.

Standard equipment on the 1500 LS 2WD ($40,635) and 1500 LS 4WD ($43,480) includes cloth interior, power locks and windows, three-zone air conditioning, leather wheel with cruise and audio controls, tinted rear windows; roof rails (crossbars are extra), folding power heated mirrors, recovery hooks, a seven-wire trailer harness, 17-inch aluminum wheels, three power outlets, AM/FM/XM/CD/MP3 sound system with six speakers, center fold-down armrest with storage, overhead console, cruise control, 40/20/40 split front bench seat with six-way power adjustment for the driver, 60/40 second-row seat, 50/50 third-row split-bench seat, and OnStar 8.0 with one-year Safe & Sound service plan.Four-wheel-drive versions add the Autotrac system that has on-pavement all-wheel-drive ability.

LS-grade options include a Convenience package with adjustable pedals, remote start, rear park assist, and rear camera display in rear-view mirror ($1,060), trailer package ($230), locking differential ($295), integrated trailer brake controller ($200), 3.42:1 axle ratio, and engine block heater ($75).

The LT 2WD ($44,145) and 4WD ($46,990) add leather seating, Bose premium sound, automatic locking rear differential, front bucket power seats and a floor console between them, cargo shade, remote start, adjustable pedals, fog lamps, rear audio controls, Bluetooth, and paint-matched mirrors, door handles and side moldings.OnStar is upgraded to Directions & Connections service, which includes Turn-by-Turn Navigation.

The very well-equipped LTZ 2WD ($52,880) and 4WD ($55,625) models add navigation, XM NavTraffic, second-row bucket seats, heated and cooled front seats, heated rear seats, perforated leather seating surfaces, three-zone automatic climate control, Bose Centerpoint Surround Sound, rear park assist, Autoride suspension with rear air assist/self-leveling, and many other features and conveniences.

A Z71 Off-Road Package ($1,830) is offered only on the LT trim level, in 2WD or 4WD.It adds a different chrome grille and fascia, rectangular fog lamps, body-colored fender flares, mirrors and door handles, tubular assist steps, 18-inch wheels with on/off road tires, off-road suspension package, automatic locking differential, skid plate, higher-capacity air cleaner, and badges.

Safety equipment on all models includes dual frontal airbags, full-length head-curtain airbags, front seat-belt pretensioners, a tire-pressure monitor, anti-lock disc brakes with electronic proportioning, and StabiliTrak, GM's electronic stability program with anti-rollover mitigation and traction control.OnStar telematics will send help if the airbags deploy and you don't respond.Safety-related options include rear park assist, rear-view camera, and side Blind Zone Alert.Side airbags are not available.

The Suburban has a square-jawed face that's smooth and rugged at the same time, a twin to the shorter Tahoe.The mesh grille is split by a gold Chevy bowtie, and the daytime running lights use separate lamps and can be switched off for after-dark campground arrivals.The bumper fascia reveals a low license-plate holder sandwiched by openings for tow hooks, with small round fog lamps at the corners like single teardrops falling from the headlamp eyes.The seam between the fascia and fenders is very tight, and a good indication of GM's solid body quality on the current generation of trucks.

The hood has two long bulges at its sides, reaching almost from windshield to grille; Chevy calls these twin bulges the power dome; we call them a good way to keep such a large expanse of otherwise-flat steel from fluttering, just as long-cab pickups have grooves on the roof.For aesthetics we would prefer if the roof-mounted antenna were centered but long, flat cargo on the roof might present a problem.

The rear liftgate is vertical, and the rear window opens independently, with both the manual and power liftgate, which is aluminum, reducing the weight and thus the effort to raise and lower it.Rear wiper coverage is average at best.The barn-door side-swinging rear doors of the predecessor model are no longer offered.

Although the lines remain the same, the Suburban's ultimate appeal depends on which trim level and wheel style and size you choose.Some are nearly void of chrome while the Z71 adds machismo with sizable fender flares and side steps so short drivers can get in and tall ones can mess up their pant legs.

The standard wheels are five-spoke, 17-inch aluminum.Polished wheels are available.Also available are 20-inch wheels that look good, but we think they are too big for grown-ups.Taller tire sidewalls yield a better ride and in most consumer-magazine testing those large-diameter wheels don't go, stop or handle any better, they just ride harder so we prefer the 17-inch wheels.The Z71 package comes with 18-inch wheels.

Cargo space is plentiful, with 137.4 cubic feet of storage behind the front seats (second row folded, third row removed); if you aren't interested in cargo space you don't need a Suburban.With all the seats in place and set for passengers, 45.8 cubic feet of cargo space is available, with 90 behind the second row with the third row removed.You'll need to lift stuff about two-and-a-half feet off the ground to load the cargo area, and rear side doors without wheel cutouts make entry and loading much easier.

Given the lift-over height at the rear bumper, it's not easy to climb up in through the back to reach things, especially since there are no grab handles; nor are there standard hooks or nets in the back.But there is a nice compartment over the left wheel well, for tools, flashlights, snow chains or the like.

Smart storage space abounds.The huge console has deep storage and a tray on top.There are two cup holders in a removable tray forward of the console, and one in each wide door pocket.There's a slot in the dash just to the left of the turn signal, perfect for coins or tickets.

The Suburban offers a choice of two or three seats in the first two rows.With a middle-row bench seat the right third of the seat folds independently of the left, easing curb-side entry to the third row or allowing skis or boards on the right with two passengers on the left.With bucket seats in the second row you can climb into the rear from either side, and those middle buckets can be released at the touch of a button, and are heated if you option right.Only full-size utilities and crossovers, minivans, and Ford's Flex offer the kind of room you find in these first two rows.

In the third row things get interesting.The seat has three belts but just two headrests, and it splits 50/50 right down the middle where a center passenger would go.If you want to slide a long item inside, the third-row gets cut to one person; an offset split would allow long items and four passengers in the rear two rows.These third-row seats do not fold flat with the floor, so if you want a long flat load deck to camp, carry building materials or dog boxes, you have to take the third-row seats out and leave them home.

Third-seat room is good compared to most three-row SUV and crossover vehicles which aren't as long, as wide or both.

Cabin materials and style show a pleasant feel and appearance more car-like than utility appliance; with woodgrain trim and leather in the upper models the only reason to upgrade to an Escalade ESV would be more power, but you'd lose 4WD trail ability in the process.

Analog instruments are more responsive than in any other (non-GM) big SUV, clearly labeled and nicely lit, as easily read at night as in daylight; gauges include a voltmeter, oil pressure and transmission fluid temperature.Steering wheel buttons handle audio and cruise chores, plus the message display panel on most models and the interface is fairly intuitive.Upper trims have adjustable pedals and the steering wheel tilts but it is offset and angled slightly to the right of the driver seat centerline.

The navigation system and audio system is easy to operate.It includes a touch-screen monitor.We set the programs we liked, and could switch from an XM to AM to FM to digital file with one finger push.OnStar has been further refined, XM real-time traffic data is available, and if you choose a rear camera without navigation the image is displayed in the inside mirror.

The driving position offers a good view over the low dash, perhaps the best visibility in truck-dom.Seats are designed for American comfort rather than European firmness, and can be ordered with heat and cooling on some models.

The Suburban 1500 engines are rated at 310 horsepower at 5200 rpm and 335 pound-feet of torque at 4200 rpm.All Suburban engines have a fuel shut-off feature, called Active Fuel Management, that cuts fuel to half the cylinders when full power is not needed.This will be most noticed on level ground at moderate, steady speeds.You won't notice when it changes back and forth, because it's very smooth.And it delivers big benefits in fuel economy.

With the 2500 Suburban there is a 6.0-liter engine of 352 horsepower.Like the others it features a tow/haul mode for less shift busyness over rolling terrain and adds a bit of compression braking.

The shifter has PRNDML positions and a thumb-operated rocker switch for changing gears manually.However, unlike every other +/- shifter, you first have to move the entire lever to the M position.

All Suburbans have four-wheel antilock disc brakes and StabiliTrak electronic stability control.Like any vehicle with ABS, press the brake pedal as hard as you can and steer and disregard any buzzing noises or vibration; that means it's working and is your best way to avoid an obstacle or accident.

Guiding a Suburban is effortless, the steering nicely weighted and direct by truck standards.At 18.5 feet long and 6.5 wide the Suburban isn't ideal for congested areas but it's quite maneuverable for its size; it needs 43 feet of road to make a U-turn (45.5 for the 2500), but that's just a yard more than some two-seaters and small sedans.So, it's pretty good, in other words.And because of its boxy shape the corners are reasonably well defined; available rearview cameras and park sensors make it easier to parallel park but it won't drop right in.An available blind spot alert system adds a warning if you didn't see the vehicle next to you; like all such systems it focuses on your car and not what might be next to any trailer you're towing.

The Suburban's 130-inch wheelbase and nearly three-ton weight contribute to a good ride quality, one of the best for any vehicle with a solid rear axle.Some competitors have independent rear suspensions that enjoy an advantage on rough roads and for spirited driving.Some people believe you must have a solid rear axle for towing and they are a bit easier to maintain, but extreme-duty vehicles like the Humvee and Mercedes Unimog successfully used independent rear suspensions.In any case, the Suburban has the traditional setup for towing.

Autoride suspension is available on some models.It monitors the road surface and driver inputs and adjusts damping as needed, optimizing the blend of ride comfort and handling grip, and also limits body roll in heavy cornering.The self-leveling rear suspension aspect of Autoride might help while towing but it is no substitute for a proper weight-distributing hitch.

The 2500 Suburban has a different feel than the 1500 but drives through the same controls.Since it is designed for heavier use, carries about 500 pounds more and tows about 1500 pounds more the bits underneath are more truck-like.It has a much stronger rear axle with a shorter ratio, Chevrolet wisely thinking 2500 owners will prioritize towing performance over empty highway fuel economy.The rear suspension uses leaf springs rather than the 1500's coil springs.

All these parts add weight so the 2500 rides a little bit firmer and isn't as quick to turn as the 1500 but it is still a very competent chassis and at full load feels like it rides and handles at least as well as a loaded 1500.Were we regularly towing 6,000 pounds, or 5,000 with the family and gear onboard, we'd opt for the 2500 and its stouter running gear.

The leaf spring rear-end on the 2500 allows a significant increase in fuel capacity, from 31.5 gallons on the 1500 to 39.0 on the 2500, meaning the 2500 will travel farther between fill-ups of weaving your trailer through gas stations.

By default all Suburbans are set up for towing, but for larger loads, such as anything more than a twin-axle bass boat trailer, consider opting for the trailer towing package (more engine oil and transmission fluid cooling), larger outside mirrors, and the integrated trailer brake controller carried over from pickups.Note that the controller may not work with electro-hydraulic trailer brakes as on some higher-end RVs; so consult your dealer.But a Suburban with this package is a fine tow vehicle, indeed.We've done major cross country tows over frozen highways and the Suburban performs admirably in this type of duty.

G.R.Whale reported to NewCarTestDrive.com from Southern California.