Photo of 1st Series Bed by Clint Dixon
Wood plank dimensions for beds.
I have checked under the bed of my WDX and learned a few things myself in the process. To make it easier, I will start at the very front and work to the back with my observations and hopefully answer your questions in the process:
Bed C-Channel #1 (front of bed) - The bed attaches to the frame, with bolts passing through this channel to brackets which are riveted to the outside surfaces of the frame rails. Fiber pads rest between the lower leg of the channel and the frame brackets. Reinforcing tubes are welded between the legs of this channel and the mounting bolts pass through these. Tabs, spot welded to the bed sides, bolt to the very ends of the lower leg of this channel. The legs of this channel extend towards the rear of the truck. Along with the mounting holes positioned out wide to correspond with the frame bracket hole locations, another distinguishing characteristic of this channel is that the bottom leg is notched for clearance to access the bolts t hat attach the bed strips to it.
Bed C-Channel #2 - There are no bed mounting bolts that pass through this channel. It only attaches with bolts to the bed strips. There are no reinforcing tubes welded between the legs of this channel. Tabs, spot welded to the bed sides, bolt to the very ends of the lower leg of this channel. The legs of this channel extend towards the front of the truck. Fiber pads rest between this channel and the frame rails. The pads have spring clips that pass through holes in the bottom leg of the channel that act to hold them in place. There is no clearance notch in the bottom leg of this channel.
Bed Hat-Channel #1 - Bed mounting bolts pass through this channel to holes in the top legs of the frame rails. The channel has extension loops welded onto the underside that reach down to the frame rails. These extension loops are reinforced with tubing through which the mounting bolts pass. Fiber pads rest between these extension loops and the frame rails. This Hat-Channel #1 is situated so that the leg closest to the rear of the truck bolts to the inner fender well. This causes the bolt pattern of the hat-channel to the bed strips bolts to be: rear, rear, front, rear, front, rear, rear.
Bed Hat-Channel #2 - There are no bed mounting bolts that pass through this channel. This channel has extension loops welded onto the underside that reach down to the frame rails, but there are no tubing reinforcements within them. Fiber pads rest between this channel and the frame rails. The pads have spring clips that pass through holes in the extension loops of the channel that act to hold them in place. This Hat-Channel #2 is situated so that the leg closest to the front of the truck bolts to the inner fender well. This causes the bolt pattern of the hat-channel to the bed strips bolts to be: front, front, rear, front, rear, front, front.
Bed C-Channel #3 - Bed mounting bolts pass through this channel to holes in the top legs of the fram e rails. Fiber pads rest between the lower leg of the channel and the frame rails. Reinforcing tubes are welded between the legs of this channel and the mounting bolts pass through these. Tabs, spot welded to the bed sides, bolt to the very end of the lower leg of this channel. The legs of this channel extend towards the rear of the truck. The mounting holes of this channel are positioned inward in order to correspond with the holes in the frame rails. There is no clearance notch in the bottom leg of this channel.
Bed C-Channel #4 (rear of bed) - There are no bed mounting bolts that pass through this channel. The legs of this channel extend towards the front of the truck. Distinguishing characteristics of this channel are that it is narrower (shorter) that the other C-Channels and its bottom leg is notched for clearance to access the bolts that attach the bed strips to it.
Best Regards,
Clint