How To Prevent A Bent Raptor Frame: ADD Rear Frame Gusset KitPosted in How To on July 1, 2012 Comment (0)
In 2009, Ford Motor Company’s high-performance F-150 SVT Raptor was released to the public and became an immediate success. Seasoned off-road enthusiasts and newbies alike have been attracted to its 12 inches of rear suspension travel with 5.5 inches of up-travel at stock ride height.
But some owners have been experiencing bent frames that leave the frame rails tweaked upwards near a narrowed rail portion under the bed, close to the factory jounce bumper (bumpstop). This damage can be further evidenced by a V-shaped gap between the cab and the front of the bed. In some cases, the lower front edge of the bed may contact the cab and cause body damage as well.
Controversy swirls as to whether the cause can be attributed to a weak frame design or is the result of drivers pushing the truck beyond reasonable suspension limits. The damage seems to occur when the rear suspension is fully compressed due to encountering an extreme dip in the terrain or slamming some trail obstacle at high speed. The frame may bend when the suspension becomes fully compressed and bottoms hard on the stock jounce bumper. If sufficient energy is still present after the suspension bottoms, the jounce bumper assembly may be crushed and the frame may mushroom outward and bend as the force is applied.
Some bent frames can reportedly be straightened while on the truck. We know of one owner that opted for a full frame replacement. We inquired to a service technician at a local Ford dealer and found the cost of a Raptor replacement frame was $4,300, and shop time for the swap job could run about 40 hours.
To Ford’s credit, the company has examined the suspension conditions and explains that the damage occurs when the vehicle hits too large an obstacle while going at too fast a speed. The frame will yield and absorb the excessive energy when it bends. If the frames were designed considerably stiffer, the residual impact energy after the suspension bottomed would be imparted to kick the rear of the truck into the air, causing possible loss of vehicle control.
The great majority of Raptors on the road remain unbent, if that tells you anything. Also, it should be noted that some of the Raptors that have suffered bent frames have also had their rear leaf springs replaced with aftermarket units. You can decide for yourself whether the frame is inadequate or if Raptors are being overdriven.
For those who are pushing their Raptors to (or past) the truck’s limits, there are a few rear frame kits out there that add strength, rigidity, and hydraulic bumpstops to the rear end. We recently watched the install of a premier frame kit over at Addictive Desert Designs (ADD) in Apache Junction, Arizona. ADD’s kit is for Raptor owners who want to run aftermarket leaf springs or are concerned about the possibility of severely bottoming their suspension and bending the frame (or both). The kit provides two formed stiffener plates that bolt onto the frame rails near the factory bumpstop and a plated tube truss that bolts on to span the forward and middle frame crossmembers under the bed.
This combination is designed to increase the rigidity and the strength of this area of the frame to prevent the rails from kinking and bending upward under hard suspension impact. King 2.5 2-inch-stroke hydraulic bumpstops are also an option with ADD’s kit, along with another crossmember that is added with the bumpstop option.
Follow along as we show you the ADD kit components and the relatively easy installation on a 2011 Raptor.
10. The King bumpstops were charged with nitrogen to a pressure of 50 psi. In addition to the increased strength benefits of this kit, the Kings offer 2 inches of stop travel to progressively slow the upward movement of the axle. This rear suspension is now ready for more confident dirt play.
Doug Hare and Andrew Rhinesmith at ADD installed the kit on this Raptor in just under an hour and a half. While the work was performed in their well-equipped shop, any owner should be able to install the kit in a driveway with a fairly basic set of tools in three or four hours.