Yahoo Autos The New Raptor's Tires Are So Big, Ford Had to Change the F-150 Assembly Line
The all-new 2021 Ford F-150 Raptor's standard-fit tires are plenty big—315/70R-17 BFGoodrich All-Terrain T/A KO2s, 35 inches in diameter and more than a foot wide. If that's not big enough, you can check the box for something even bigger: 37-inch BFGs, the largest tire ever offered from the factory on a light-duty pickup truck. These huge tires give the new third-generation Raptor even better ground clearance for off-roading—and they're so big, Ford had to modify the F-150 assembly plant to fit the new Raptor with 37s.
"Imagine those monsters and how we’re dealing with them in the assembly plant," Tony Greco, program manager for the third-gen Raptor, told Road & Track. "It’s a big, big truck. It’s bigger than F-150 and it got taller than the last Raptor. We had a lot of help from the assembly plant who understood what a game-changer it was for us."
The height was the major problem. With the optional 37-inch tires, a 2021 Raptor stands 80.7 inches tall—a shade over six-foot-six. "Getting it into the plant, that went on for 15 months to find the solution," Greco said. "Every single station, every single piece of equipment ... We’d run a 2020 Raptor [through the factory] with foam blocks on top to simulate the height. Constant digital reviews with the manufacturing team ... They took every down week in the summer and over Christmas trying to change the cycle line to make provisions for what was coming. In the end, we found a really clever way to execute it."
The first two generations of Raptor offered 35-inch tires, a pretty revolutionary achievement in factory off-road vehicles when the first truck debuted in 2010. Getting a two-inch-larger tire to fit under the third-generation truck required significant finessing. Ford completely redesigned the new Raptor's suspension, with coil springs on the rear axle for the first time in F-150 history. The 37-equipped Raptor actually loses some suspension travel—13 inches in front, 14.1 at the rear, compared to 14 front and 15 rear on a truck with 35s. The front shock absorber is upgraded with a larger rod, and 37-equipped trucks have a different spring perch location for the front suspension. The rear suspension—an all-new five-link setup with Panhard bar—gets unique shock absorbers and bump stops as part of the 37-inch tire package.
The huge tires even required modifications to the frame. Ford was adamant about equipping every Raptor with a full-size matching spare mounted under the pickup bed, and that meant finessing the frame shape and designing a new spare tire mount unique to 37-equipped trucks. The trailer hitch had to move, too, though all Raptors will share the same hitch. (There's an optional appearance package for 37-equipped trucks, a decal set that includes the number 37 in various places on the bodywork, but it's not required with the big tires.)
All of this is why the 37-inch tires come as part of a larger option package including a unique wheel design—and why you won't be able to outsmart the factory by buying a 35-equipped truck and swapping on 37s after the fact.
"The biggest thing is the stowing of the 37-inch spare. The frame that comes with the 37-inch configuration is unique to the 37-inch truck," Greco said. "A guy that gets a 35-inch-equipped truck and decides he wants to put on 37s, he’s never going to get a 37-inch spare underneath there."
So, with all that work done to fit a 37-inch tire, is there room for anything bigger in those wheel wells?
"From our Ford processes, we would say that's not compatible," Jack Cooper, a supervisor at Ford Performance, told Road & Track. "Put it this way," Greco added, "it didn't stop me from asking Jack the exact same question an hour ago."
Cooper continued: "Frankly, the 37s are something we saw people do to the truck for years. We’re always trying to keep track of what people are going to do in the aftermarket, and seeing if we can offer that value and performance benefit from the factory. But we do have a lot of rules in place to protect customer as well. Right now I can’t see us passing our internal metrics with larger wheels and tires. But our internal metrics ... I’ll say, they’re robust for good reason. Not everybody will find they need all that robustness in the field. We would say the 37 is the biggest tire that fits according to us."
Right from the beginning of the third-generation Raptor project, fitting 37s was a goal for Ford. "We put foam blocks all over that thing and jumped the hell out of it and made sure that tire fit the way it’s supposed to according to our Ford processes," said Jeff Nichols, powertrain engineer for Raptor. "That’s pretty unique for an off-road truck."
"We really had to sharpen our pencils in a lot of ways," Cooper added. "Like Jeff’s saying, we had to really dig deep into our test results and figure out where can we optimize this thing. We had to take advantage of every available piece of space we could get. We tested this thing, it works."
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