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Stoneway Concrete Realizes Greater Payload, Enhanced Stability with Kenworth T880, PACCAR MX -11 Engine

When Ralph Lo Priore looks at which new specification choices would likely work best for his company’s trucks, he prefers to deal in cold hard facts, not egos or emotions.

When Ralph Lo Priore looks at which new specification choices would likely work best for his company’s trucks, he prefers to deal in cold hard facts, not egos or emotions.

“Too often people make purchasing decisions on what’s always been done before,” said Lo Priore, director of fleet assets and processes for Stoneway Concrete and its parent company, Gary Merlino Construction Co. “Instead, I like to look at what’s going to deliver the best return on investment in terms of reliability, durability, serviceability, longevity and a lower cost of operation.”

Stoneway and Merlino operate a combined fleet of 150 trucks, including 85 transit mixers and 60 dump trucks from three locations – the company’s maintenance shop in Renton, Washington, a yard in South Seattle and another yard next to Ashgrove Cement in Seattle.

When it came time to choose a new engine platform for Stoneway’s mixers, Lo Priore examined the data and chose the new PACCAR MX-11 engine platform with two Kenworth T880 mixer chassis for Stoneway Concrete. After those two T880s with the MX-11 proved their worth in operation, Lo Priore ordered nine more new similarly spec’d T880 mixers.

PACCAR MX-11 Engine

 “I look at, for example, the company’s maintenance data, which helps me identify issues caused by bad spec’ing decisions, like equipping a truck with the wrong suspension,” Lo Priore said.

Of course payload is always a major consideration, Lo Priore added. “Our customers are always wanting more yardage with fewer trucks on the job. That’s why when I looked at how many times the company sent out one more mixer to a job site with short loads of concrete to finish up the job, I knew Stoneway Concrete needed trucks with more payload capacity.

“But trying to get that additional payload by going with the same 13-liter engine and looking for weight savings in other places, or going bigger with a 15-liter engine in applications other than the mixers, were just not the right options,” he said.

Lo Priore also credits the new model’s success to a decision to go with a set-back front axle and a total of seven axles, including a conventional “boost-a-load” axle, allowing for an 80,000-pound GVW, which is allowed under Washington state’s bridge formula. Lo Priore said he saw the more typical 76,000-pound GVW design with an 11-yard mixer as being “obsolete.”

While many questioned those choices, Lo Priore said he felt confident they were the right ones. That’s because with the PACCAR MX-11, the tractors and mixers realize a better horsepower-to-weight ratio and gain payload capacity. And with the combination of the MX-11 and set-back front axle, the T880 mixers can carry 4,000 additional pounds of payload by redistributing the weight to the pusher axle when needed.

The additional payload capacity means the mixers can carry up to 12 yards of concrete per load instead of the usual 10-1/2 to 11 yards the typical 76,000-pound GVW Stoneway mixer equipped with a 13-liter engine would carry. With a 12-yard capacity, the T880 mixer with PACCAR MX-11 engine can generate an average of $315 more in daily revenue than a 10 1/2-yard mixer. Stoneway Concrete’s mixers typically run six days a week year-round, and as a result the T880 mixer can earn about $98,000 more in annual revenue, according to Lo Priore.

The lighter engine, set-back front axle and addition of the pusher axle all changed the T880’s center of gravity, allowing McNeilus to install a wider drum, Lo Priore said. By pushing the front axle back, the drum also sits lower on the frame, which results in increased stability and reduced drum bounce, in on- or off-road conditions.

“By choosing the PACCAR MX-11, we have a 400-pound lighter engine compared to a 13-liter engine, but with the same 430 horsepower,” Lo Priore added. “The MX-11 engine, with its compact graphite iron head and block, is much lighter and more durable than an engine made of gray cast iron. With the Allison 7-speed automatic transmission, it’s a perfect combination.

Dan Leenhouts, Stoneway Concrete driver, is shown with a Kenworth T880 mixer equipped with a PACCAR MX-11 engine.

“Allison’s dynamic shift sensing allows the transmission to automatically choose gears based on the vehicle’s weight and the road grade. So, drivers get a state-of-the-art truck that doesn’t leave them tired with aching knees and shoulders from all of the shifting they have to do in city traffic,” he said. “And the Kenworth T880 provides us the right chassis because of its design, which makes for a more comfortable work environment and offers a field of view drivers simply can’t get with the other available truck models.”

Dan Leenhouts, who was assigned that first Kenworth T880 mixer with the PACCAR MX-11 engine in 2015, was so impressed by it, he chose to forgo his retirement in 2016 and continue working another two years for Stoneway.

“The Kenworth T880 offers such a phenomenal ride,” he said. “When I first drove it, I just could not believe how quiet it is in the cab. Because the MX-11 provides good power and smooth acceleration, I find the T880 is able to keep up with the other trucks with larger engines, even lugging under load on hills."

“I’m also very, very pleased with the visibility from the cab,” Leenhouts said. “The mirrors are so perfectly positioned giving me the ability to maneuver well in heavy traffic. With its sloped hood, driving the T880 is almost like driving a cabover.”

Lo Priore said it wasn’t easy to get a concrete mixer equipped with a set-back front axle, an 11-liter engine, and seven axles including a pusher axle, built. After he shared data from Stoneway’s conditions-based maintenance program, “Kenworth was the only OEM willing to try,” he added. Lo Priore credits Rick Barry, territory sales director at Kenworth Northwest, and Kenworth technical engineers in making the spec happen.

From left, are Dan Leenhouts and Ralph Lo Priore of Stoneway Concrete.

“Now that we’ve proven what this new spec can achieve, I take pride that there’s a lot of other companies looking very hard at whether this new specification can work for them as well as it has for us,” Lo Priore said.
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