Supply constraints will keep Class 8 retail sales at about 196,000 units in North America despite market demand for as many as 275,000 trucks, according to Mark Lampert, sr. vp of sales and marketing for Freightliner Trucks.

Freightliner parent Daimler Trucks North America (DTNA) “has pretty much been sold out for 2011 for almost two months, although we still have some Class 6/7 availability,” Lampert said at a press conference.

DTNA expects that the unmet demand coupled with stepped-up production at the major component manufacturers should help push retail sales in 2012 to approximately 258,000 Class 8 trucks with peak demand in the first and second quarters, according to Lampert.

Replacement demand rather than fleet expansion is driving Class 8 sales as average fleet age continues to increase and used truck prices are “up dramatically,” said Lampert. He estimated that “the new normal” replacement level is 175,000 to 180,000 trucks a year, down from 210,000 to 220,000 trucks in the first half of the decade.

DTNA forecasts Class 6/7 retail sales in the U.S. and Canada at 92,000 trucks this year, growing to 108,000 trucks in 2012. The company sees overall NAFTA retail sales for Class 6-8 totaling 286,000 units this year, up 33% from 2010 and 48% from the market’s low point of 187,000 units in 2009. That robust recovery is expected to continue in 2012, with the company’s NAFTA Class 6-8 retail sales forecast at 367,000 trucks.