When it comes to car payments, consumers are stretched to the limit.

Buyers are paying more, extending loan terms and making smaller down payments, according to a recent study by the Consumer Bankers Association. Many buyers are also wrapping old loans -- for vehicles they haven't yet paid off -- into the terms of their new deals.

"They're stretching in a lot of cases and may be well advised to pick a more affordable model or keep their car a little longer," says Fritz Elmendorf, vice president of communications for the Consumer Bankers Association.

Sixty percent of buyers are opting for loan terms of more than five years, the study found.

"It's been steadily stretching for many years," says Elmendorf. And it's because buyers want to get a better quality car and still keep their payments low.

"So many have gotten used to lease payments," he says. "They're looking for the cheapest payment on the nicest vehicle they can get into."

The average loan is now about 65 months and gradually getting longer, says Tom Libby, a senior director of industry analysis for J.D. Power and Associates.

Last year, buyers were typically paying 5 percent of the invoice price as a down payment, according to the study. This year, that's dropped to 1 percent.  Manufacturer and dealer incentives could account for part of that, but it's also clear more buyers owe in excess of what their cars are actually worth -- one side effect of making lower down payments.

"They are increasingly upside down in their loans," says Elmendorf. "And the longer the loan period, the longer you're upside-down in your loan.

A combination of longer loan terms and less money down is adding another complication for consumers: "More people are going in owing money on a trade-in, as opposed to being able to add value for the trade in," Elmendorf says.

Jack Nerad, executive editorial director of Kelley Blue Book, agrees.

"We're seeing a lot of  100 percent loans, or loans with 5 to 10 percent down," Nerad says. "Twenty percent used to be the standard."

"People have less equity in their cars," he says. "But it doesn't seem to have had a chilling effect on sales."

So how much are they rolling over into the new loan? On average, about $2,600, says Art Spinella, president of CNW Research, an Oregon-based consumer spending research company.

Consumers are also buying more options and upgrade packages on the models they select, Spinella says. "They're buying more car," he says. "They're not buying base cars anymore."