I am in the final stages of designing the flatbed for my truck. It's going to be 8' long and almost 7' wide. I think I have settled on 3" channel for the crossmembers with treated 2x6's on top. 4" channel on the sides with many stake pockets welded on. I think I'm going to put 2" spacers under the channel to raise it up enough to get tire clearance and cut the wood out over the tires and use a steel plate on top for even more clearance. Total clearance over the tires should be 4-4.5". The hitch settles around 3.5" with a full cord of wet wood on it, so I figure it should be around 2- 2.5" at the tires. The bed would be ~36" off the ground, which is as high as I want to go. I still have airbags on the rear axle that I can hook back up and have them kick in around 1.5-2" of sag, just to keep tire clearance at heavier weights. I already have the leveling valve for the airbags. The springs are pretty stiff (6k lb rating), but I want to make sure I leave enough clearance. should I use 3" spacers for another inch of clearance? I suppose I could get the bed welded up and then use whatever spacer I need to set clearance.... What do you guys think?
With airbags to help out I think you should be good. I like the idea of steel plate over tires. I assume that means your spacing the cross members front and rear of the axle center line. My dad had a factory built flatbed that was generic fit for most 3/4-1 ton chassis's. That bed had a cross member too close to the centerline of the rear axle and we smoked the tires pretty bad the first loaded trip. He added timbren solid polymer bumps top replacements to keep the truck from sagging as much.
Yes, the crossmembers are going in the same spot as the factory ones, for a total of 6. I can move them a little (along the risers/spacers), but not much. I'm hoping to keep the finished weight under 600 lbs, which is tough.
The next one I do, I’m going to incorporate a hydraulic dump into it. It’s not much money for a hydraulic power pack, cylinder and hose(s) these days. Sent from my iPhone using Tapatalk
I have a brand new 8 ft stroke telescopic cylinder I bought just for this, but making it a dump will add a lot more weight, and I'm not sure if I need a dump that bad. I could put it on a trailer. My original design involved using the power steering pump to power the cylinder.
Problem is that a telescoping cylinder takes a large volume of fluid to extend, more than the steering system holds. Additional reservoir capacity (rather large) could be added but offers some challenges.
Mounted to the Frame under the front corner of the bed is where I normally see the reservoir or power unit mounted. Couple of upside down L brackets for it to set on. I think you have to modify the ps pump if you go that route. I used this on a dump trailer and a wrecker unit in a shop truck. This is single acting and gravity down but doubleacting is only a bit more expensive. Single Acting Hydraulic Power Unit, 12V DC 10 Quart Hydraulic Pump Sent from my iPhone using Tapatalk
If using a trans mounted pump that's a common location. Using the power steering pump will require modifications as you suggested although I would expect cavitation if the reservoir is far away and below the pump especially in winter.
Don't forget axle articulation. If you drive it off the road much, leave some room for the tars to push up into. This is usually my only issue with home made flats. Have seen many varieties from fanciest pipline welders to gravel road farmers. So long as it works for the one who built it, surely I'm not able to criticise (other that the wheel well issues). <<<gooder enough for who it's for.
