Ford’s F-Series trucks have become the world’s most popular pickups. But even with the newest and best F-150 lineup, the automaker and the people who drive them must see competition gaining in the rear-view mirror.

It’s approaching in the form of the 2007 Chevrolet Silverado, this year’s North American Truck of the Year. And rumbling up from a new plant in the heart of truck country, Texas, comes another worthy pickup — the Toyota Tundra, which is bigger and more powerful than ever and comes in myriad variations.

The bumps in the road are already being felt by Ford. According to the trade journal Automotive News, F-Series sales in 2006 were 796,039, down from 901,463 the year before. They have continued to fall this year, down 13.4 percent in the first two months.

Still, this hardly means that bad times are ahead for a truck whose roots reach back to 1948 when the F-1, F-2, and F-3 trucks hit the market. That started a remarkable run of automotive endurance, spawning the phrase “Ford Tough,” because the trucks were capable of performing imposing work on farm fields and construction sites.

Today, however, family-friendly is a moniker that is equally important, and our test model F-150, the 4×4 Supercrew (four-wheel drive, four full doors) Lariat, passed that test. But despite the friendliness, it remains big — with a 150-inch wheelbase — and tough, just like earlier F-150s.

Our test model came with standard front tow hooks, locking removable tailgate with lift assist, defrosted privacy glass in the rear, leather-wrapped steering wheel, a power driver’s seat, two-speed transfer case for tough slogging, shift-on-the fly four-wheel drive, and antilock brakes. The base price of about $35,000 got jacked to about $42,000 with the addition of a limited slip axle ($300), a navigation/upgraded audio package ($1,995), a power sliding rear window ($250), 20-inch aluminum wheels ($895), leather-trimmed captain’s chairs ($695), and a few other goodies.

That’s still not a lot of money for a utilitarian truck that can go to the construction site, haul plenty of lumber for weekend projects, beat its way through bad weather and rough terrain, but also provide a family of six with all the comforts of a luxury SUV.

But some updates are needed. The 5.4-liter V-8 engine needs to be more fuel efficient, and the transmission — a four-speed automatic — lags behind what some other companies are offering. For example, General Motors and Toyota feature six speeds.

And the handling of the F-150 is definitely more skittish on bumpy roads than the Tundra or Silverado.

Not that it is weak and coltish. The F-150 generates 300 horsepower and 365 lb-ft. of torque. The transmission is smooth in upshifts and gentle in downshifts, though it can get a bit loud when pulling out to pass. This is where a fifth and sixth gear — and perhaps a better engine — would help.

And don’t worry, better engines seem to be on the way. Reports out of Detroit say the next generation F-150 will likely be unveiled for the 2009 model year. It will feature upgraded diesel, V-8, and even a hybrid gasoline-electric power plant that can be linked to a six-speed automatic.

For now, though, the 2007 F-150 remains in the game, despite the competition.

THE BASICS Base price/as tested: $35,465/$41,965 Fuel economy: 15.1 miles per gallon in Globe testing/regular fuel Annual fuel cost: $2,307 (at $2.68 per gallon, regular, 13,000 miles per year)

THE EARLY LINE The F-Series has been lead dog on the sled for a long time, but there are new pups in town.

THE SPECIFICS Drivetrain: Four-wheel drive Seating: Five or six Horsepower: 300 Torque: 365 lb.-ft. Length: 235.8 inches Wheelbase: 150 inches Height: 76.0 inches Width: 78.9 inches Curb weight: 5,343 pounds

THE SKINNY Nice touch: Clean, easy to use, and roomy interior — you’ll forget you are in a big pickup truck. Annoyance: Gas consumption. Even 2 miles per gallon more would be a great upgrade. And imagine if all light trucks, got 2 more mpg. They make up half of our auto sales. Watch for: New engines, new transmissions, and a redesign. Before long, Ford trucks will be ahead of the curve.