Help! Please With Wooden Flatbed for Pickup

Help, my truck bed rusted off so I removed it and need to build a wood flatbed ASAP. I want to have a 8' wide x 8' long flatbed but I need it to go over the wheels, no wheelwells. Any idea on what to use for the cross supports with price being the most important consideration. The deck needs to have 8" clearance above the tires if I calculated right, the truck is a GMC Sierra 1500 6 lug. I was thinking of using 4x8's or using two 2x8's bolted together for the cross beams and then 2x12 for the decking. I need it to be strong enough to hold hay stacked up high but I don't need it to last forever as the truck only has about a year left if that. The overhang over the wheels will be 2' on each side so the cross beams need to be strong enough to hold weight on the overhang. There will be 4 cross beams. Maximum load on the flatbed will be ~3000 lbs.

To get the level base at the right height on wrecker bodies, I have clamped two pieces of angle iron together to make a channel iron. Once set to the right spacing, just weld or bolt them together. Generally, your looking for something around 1.5-2" X 3-4" or similar and make them the length of the flat parts of the frame front and rear. F & R can be different heights too.

As the saying goes "...make lemonade". I'd figure out how to make sure main beams were resting on the frame and hinged on the back. Get a small hand pumped hydraulic jack to lift.

Even 2X8's sounds excessive. I'd probably build a 2X4 "wall" for the decking to go on. Then run 2 - 4X6's (or beeter yet some c-channel) the length of the truck perpendicular to the 2x4's against the frame to facilitate the "lift". Finally run cross angled 2x4's from the 4X6's to the the outer edge of the 2x4's. That last step will not add much weight, be cheap and most importantly add a tremendous amount of strength. All the weight on the outside of the bed is directly transferred to the 4X6's. This believe it or not would probably be much stronger than simply building a 2x8 wall. You're adding angles and structure to the design. More cutting but the end result is more desirable, less weight and more strength. I can draw it up if you can't visualize what I'm saying.

As far as the decking, either three quarter plywood or decking. Be sure to use metal brackets at all joints.

Dont' use 2x12's for the decking. Too expensive and too likley to warp. I'd use 2x6.

If you use plywood (a lot lighter, you can carry more weight) get the marine grade and seal it well.

coaledsweat wrote:get the marine grade and seal it well.

Have you priced the marine grade plywood?
You may want to sit down.

Yea, plus it would need a much more extensive closer together frame under it to screw it too or it will lokk like the PA countryside. The edges won't hold up well either. If you think 2x6 pt would be too heavy, use 5/4 decking. Either way it will be lighter than the original truck bed. I'd go with 2x6 pt. Gives you the ability to attach tie down hardware without worry, etc. A friend of mine used rough cut saw mill lumber(oak) on his. It held up longer than the truck did.

coalkirk wrote: use 5/4 decking.

Ya beat me to it. Just what I was thinking while reading the posts. I saw a truck once with 4x4's hand shaped to fit both sides of the frame (length) with the deck built off that. As the frame went back it raised a bit. The hand shaping made it even. Then it had 4x4's across with the 5/4 decking to them. The deck perimeter edge was surrounded with angle iron. Nice clean job.

Richard S. wrote:As the saying goes "...make lemonade". I'd figure out how to make sure main beams were resting on the frame and hinged on the back. Get a small hand pumped hydraulic jack to lift.

Hmmm... interesting Richard. I've been thinking about making a trailer to pull with my tractor for yard work. I hadn't thought about a dump.

Have you tried to get another bed or are you set on making a flat bed ???

Most of the insurance companies that I deal with use http://www.car-part.com/

I checked and they have some as low as $500.00 You could probably drive there and get it set on at the junk yard.

Or at the least you could buy one with damaged sides, cut them off and then add the plywood to make it longer and wider. This way you would have all of the bottom mounting structure.

Rick

Rick, the truck isn't worth a $500 bed. I don't even like to fill the gas tank. I was going to just scrap it but it still runs good so I figured it's worth $100 worth of wood and hardware to get it usable again.

With the price of scrap steel as high as it is you may want to junk it rather than put money into it if it is in that bad of shape.

I could scrap it but then I gotta buy another truck and I'm not ready for that yet. Next truck I buy is coming from a southern state with no salt on the roads, I'm sick of dealing with rusted out junk.