(REUTERS) -- Automakers expect lower sales growth in the United States in 2012 because the economy remains weak, even though U.S. auto sales in December were strong.
General Motors Co's U.S. sales in December rose about 5 percent, while sales at Ford Motor Co and Chrysler jumped 10 percent and 37 percent, respectively.
U.S. new-vehicle sales are an early indicator each month of consumer spending, and the United States is the world's second-largest auto market behind China.
Automakers are headed for full-year 2011 sales of about 12.8 million vehicles, 10 percent higher than 2010. U.S. auto sales have been a relative bright spot, with many cash-strapped consumers forced to purchase cars and trucks to replace vehicles that have been on the road for a decade or longer.
GM, Ford and Volkswagen AG , which reported a 36 percent gain in December, all said growth would increase at a lower rate in 2012.
GM and VW expect 2012 U.S. sales in the range of 13.5 million to 14 million vehicles, which implies growth of between 5 and 9 percent. Ford sees a range of 13.2 million to 14.2 million, excluding medium and heavy-duty trucks.
The momentum coming out of the fourth quarter gives us confidence that the low end of that forecast is less likely, Ford economist Ellen Hughes-Cromwick said on a conference call.
Industry research firm TrueCar.com expects 2012 U.S. auto sales to reach 14 million vehicles.
That is still much lower than the nearly 17 million in U.S. annual auto sales averaged in a 10-year period through 2007. In 2008, recession began to take hold and a year later GM and Chrysler filed for bankruptcy.
Over the course of the fourth quarter of 2011, clear signs emerged that U.S. consumers are more confident and that other underpinnings of our economy are either stable or slowly improving, GM U.S. sales chief Don Johnson said in a statement.
It's now clear that auto sales should continue to grow in 2012, barring a shock to the system, he added.
Jonathan Browning, who heads VW's U.S. operations, said the automaker chose to give a forecast range for 2012 sales because of uncertainties including the U.S. presidential election and the debt crisis in Europe.
It just reflects the macroeconomic volatility we see around the world, Browning said of VW's forecast. It's wise to have some flexibility in your plan.
Industry executives have repeatedly said pent-up demand would boost U.S. growth in 2012 because the average car on the road is 11 years old. Ford estimated that about 50 million vehicles, or one of every five on the road, is now 11 to 15 years old.
Automakers appear to be more disciplined about the types of sales deals they offer consumers. Incentives fell about 3 percent in December, according to TrueCar.
The picture in other markets is mixed. Sales in Western Europe are expected to reflect that region's economic hard times, but in Brazil auto sales are seen rising 4.5 percent this year, compared with a 2.9 percent increase in 2011.
GM's increase in U.S. sales in December was due to strong demand in its Chevrolet brand, where sales rose almost 9 percent. Sales of the Cruze small car jumped 54 percent, while the Sonic subcompact increased 42 percent compared with its predecessor car, the Aveo.
Ford's U.S. sales were helped by its best retail sales month since 2005.
The gain at Chrysler, which is controlled by Fiat , was due to a refreshed lineup of cars and trucks.
They've done a remarkable job sprucing up their vehicles, said Edmunds analyst Michelle Krebs, adding that Chrysler was coming off a low base of sales in 2010.
Krebs credited last year's Super Bowl halftime TV ad, featuring rapper Eminem, for raising the brand's image with consumers.
For the year, sales at Chrysler finished up 26 percent, and the automaker said it gained 1.3 percentage points of market share.
Nissan Motor Co Ltd's <7201.T> U.S. sales rose 7.7 percent in December.
The annual sales rate for December, according to a Thomson Reuters poll of 30 analysts, is expected to rise about 9 percent from a year earlier to 13.6 million vehicles, topping 13 million for the fourth straight month. The December 2010 sales rate was 12.5 million vehicles.
GM shares were down 0.4 percent at $20.97 at midday on Wednesday, while Ford shares were up 2.6 percent at $11.42.
(Additional reporting by Kevin Krolicki in Detroit; editing by John Wallace, Mark Porter and Matthew Lewis)