"We are now asking ourselves what is the QX70's role? And what should it be?" Krueger said. "We think about what it was created to be, as the FX. But what should it be now?"
When it debuted as a 2003 model, the FX stood out from the then-standard assumption that SUVs were supposed to be outdoorsy and rugged. The FX, nicknamed the "Bionic Cheetah," featured a low roofline and a prominent hood.
Randy Parker, vice president of Infiniti North America, said the company stocked up on inventory of both crossovers over the summer to make it through the winter, when Infiniti typically has a strong retail volume.
"We think we have a really good plan," Parker said. "We'll have enough inventory to run out just as we launch the new QX50. We have enough to get us through the peak selling season in November and December."
The company is not saying when its plans for the larger QX70 will be revealed.
Infiniti sales have been rising in both the U.S. and globally. U.S. sales totaled 113,714 through September, up 18 percent from a year ago.
Infiniti last year added the small Mercedes-Benz-based QX30 crossover to its portfolio, and the QX50 has had unpredicted late-life success.
Introduced in 2007 as the EX, the crossover hobbled along for years with scant sales.
When the aging product was re-engineered to create a larger and more practical back seat, U.S. sales took off.
Its 2016 volume of 16,973 sales represented a 210 percent increase from 2015.
The company also has a freshened full-size QX80 SUV coming at the end of this year, Parker said.
"From a crossover and SUV perspective, we're poised to ride this wave for quite some time," he said. "The future portfolio looks good for us."
The redesigned QX50 will feature a variable-compression engine, developed by Nissan and Renault. Krueger said the new crossover will hit a sweet spot in the global premium market.
"There is a larger trend in downsizing going on across the industry, around the world," he said. "That's where our QX50 is coming in. It's the biggest growth segment, not only in the U.S. but in China."