It's a radical path Bruce Stockton is contemplating — keeping a Class 8 tractor for its entire usable life cycle, roughly 10 years or one million miles. It's a concept that flies in the face of current thinking — a three- to five-year trade cycle targeted by most big truckload fleets — and it would deny a lot of good iron to the used truck market.

Yet Stockton, vp-maintenance and asset management for Joplin, MO-based Con-way Truckload, sees some distinct advantages. For starters, Con-way Truckload's trade cycle would not change. Instead of heading to the used market, those long-haul, dual rear-axle sleeper tractors would be converted to single rear-axle day cabs to serve in pickup/delivery and line-haul operations at its brother company, Ann Arbor, MI-based LTL carrier Con-way Freight.

More importantly, the parent company for both carriers, San Mateo, CA-based Con-way Inc., owns a trailer manufacturing facility that could easily handle the sleeper-to-day cab conversion in-house at a potentially lower cost than what an outside firm could provide.

Stockton envisions several benefits: a lower total cost of ownership per truck for each fleet (TL and LTL), avoiding a potential loss in residual value and denying competitors a truck specification advantage.

“We're very focused on developing as fuel-efficient a truck as possible,” Stockton said in a speech at the 33rd annual Truck Blue Book Workshop in Aspen, CO, in October. “So we don't want to take that spec package we've developed and put it into the used market where a second buyer can use the operational cost savings from those specs to compete with us.”

Preventing a loss in residual value also looms large in Stockton's mind, largely due to the preponderance of Caterpillar engines powering Con-way Truckload's fleet.

“We made the switch to Cat in 2004 because we didn't believe in the EGR [exhaust gas recirculation] emissions control solution,” Stockton said. “Not only did we get great service from local and national Cat dealers, but we didn't see any difference in fuel mileage compared to our previous engines. It's a shame Cat is leaving the [on-highway engine] business and that we'll be losing that resource, but we don't think we should suffer lower residual values because of it.”

Right now, the fleet's primary configuration is a 224-in. wheelbase Kenworth T660 equipped with a Caterpillar C15 engine and 13-spd. manual transmission, with Michelin X-One wide-base tires on the rear axle.

Over 1,200 trucks in Con-way Truckload's fleet of 2,856 tractors are due to come out of service in 2009, which is why the company is taking a long, hard look at the resale issue. Stockton said each truck is undervalued on the used market by $10,000 — so he believes converting it to a day cab tractor for LTL service at 375,000 mi. for $10,000 to $12,000 per unit would be a win-win for the whole company.

“Why take a $10,000 loss in residual value if we can instead put that truck with our brother company for the same amount and keep it away from a second buyer who would use it to compete against us?” he said.

The key to making that conversion plan work hinges on the total cost of ownership for the vehicle. Right now, Stockton would have to convert the rear-axle, wide-base tire set-up back to duals for LTL operation as Con-way Freight isn't yet sold on the benefits of wide-base tires. The C15 engine is also bigger than what's currently needed for LTL service, which could result in more fuel burned.

Those are the only major issues, so far however, as LTL drivers testing a prototype conversion have lodged no protests over using the TL-spec'd 13-spd. transmission — a big step up from the typical 9-spd. they use now.

Stockton also believes that those on the LTL side of Con-way can be convinced to stick with wide-base tires, which would help drop the conversion costs. “The data we've gathered from our fleet shows that Michelin's X-One gives us a 3.4% improvement in fuel economy — about 2/10th of a mile per gallon,” he said.