June 4 (Reuters) - Heavy discounts of up to $16,000 per vehicle are fueling a "truck war" among full-size pickups sold in the United States by the Detroit Three, a Reuters analysis shows.
Strong U.S. sales this year of the highly profitable big trucks have helped offset lagging passenger car sales.
But it is not clear how much of the truck demand is linked directly to ample factory incentives and dealer discounts, or how far sales might decline without those subsidies.
A Reuters survey of Ford, General Motors Co's Chevrolet and Fiat Chrysler Automobiles's Ram truck dealers across the United States indicates stores are offering deep discounts on some of the country's best-selling full-size pick-up trucks.
"The walls are not crashing down on full-size trucks," said Sam Fiorani, vice president of global vehicle forecasting at AutoForecast Solutions in Chester Springs, Pennsylvania. Detroit-based automakers want to keep cranking out their high-margin trucks, he added, and "giving up a little of the profit is the cheapest way to do it."
Stores are offering discounts of up to $12,000 on the 2018 Ford F-150, which remains the best-selling vehicle in the country, recording more than 80,000 sales in May.
Discounts run up to $13,000 on the 2018 Chevrolet Silverado and as high as $16,000 on the Ram 1500.
Average transaction prices for full-size pick-ups range from around $42,000 to $45,000, industry analysts and automakers say.
All three companies are spending furiously - GM and Fiat Chrysler to help sell off carryover 2018 trucks to prepare for redesigned 2019 models, and Ford to sustain its long-held sales crown.
A supplier fire that temporarily shut down production of the F-150 last month "changed the game," said Jeff Schuster, senior vice president of forecasting at LMC Automotive in Troy, Michigan said.
The supply halt nudged Ford's crosstown rivals "to ratchet up incentives on the current models to go after weakness at Ford," he said.
Deals advertised on the companies' official websites range from rebates and low-interest loans to ultra-cheap lease rates, but they are not telling the whole story.
Ford, for instance, advertises a $2,000 rebate and a $500 financing credit on sales of certain F-150 models.
But James Collins Ford in Louisville, Kentucky, is offering discounts of up to $12,215 on the 2018 F-150 XLT SuperCrew 4x4.
The price cuts are even steeper at a number of GM and Fiat Chrysler dealers.
Quirk Chevrolet is selling the 2018 Silverado 1500 Double Cab at $13,000 off sticker. Gurnee Chrysler Dodge Ram Jeep outside Chicago is marking down the 2018 Ram 1500 Harvest Crew Cab 4x4 by up to $16,000. (Reporting by Paul Lienert in Detroit, Editing by Rosalba O'Brien)