My goal was to have a build a rack system somewhat like what they have at pipelineracks.
I wanted a solid system without straps or need to crawl into the back of the truck. It also had to be adjustable to different sizes of wheels.
The key to the no-strap system is the one ratchet strap :~). The tension from the strap is pulling the base pipe toward the cab and forcing the cross bar/board to bind against the top lip of the truck bed. It is passed through the 3/4 inch EMT tubing with a plumber's fish tape. The bend on each end is about 80 degrees.
The measurements for the pieces will vary by the size of your truck bed.
The outside black 2x4 pieces need to be about 37 inches on the top side, but measure twice - cut once. They need to be short enough to miss the brake disc. The middle 2x4 pieces are about 17 inches - they need to miss the rear de-railer.
If you need help getting the angles correct just Google for "right angle triangle calculator". You want measure the hypotenuse from the point under the top lip of the truck bed to the bottom corner of the 2x4 touching the base board.
The pipe bend will eat up about 9 inches so measure the gap in your bed, add 18-20 inches to get the length of the base pipe. Make sure to file the inside edges of the opening - the strap will be passing through there under a lot of pressure and could easily cut the strap if the bend angle isn't straight toward the anchor tie down.
The holes in the 2x4 are 1 inch in diameter. They need to be at about an inch back from the edge and in the same spot on each 2x4 to allow them to slide and all push against the cross board and base board together. Slide the hose clamps and 2x4s onto the base pipe first one at a time. Then do the top pipe.
The cross board and base board are just some scrap OSB siding I had laying around. I cut them to fit the truck bed and placed half inch holes where I wanted the toe straps to pass through. The toe strap is really only needed on the middle rack. The cross board is attached to the two outside 2x4s with a single wood screw. The rest of the 2x4s are left unattached so they can slide.
The brace pieces are bolted to the base board with two 2-1/2 inch carriage bolts. The inside pieces are attached with wing nuts to make them adjustable for wider tires.
Each of the three racks were bar clamped snugly around a bike tire then fixed by tightening the hose clamps down around them. Use a socket drive on your drill to make this easier. I put finger adjustable hose clamps on the middle rack for a "guest" bike.
Step 1: You Will Need
Base board and cross board - OSB siding
3 - 8 foot 2x4s
2 - 10 foot 3/4 EMT conduit tubing
Pick up some hand tightened too (optional)
2 - wood screws
8 - sets of 2.5 carriage bolt hardware. (4 nuts/washer and 4 wingnuts/lock washers)
Circular or Miter saw or both
Pipe bender and Pipe cutter
T-square (when measuring the tubing bend angle)
Bar clamp (optional but helps to fit the tires to the gaps)
Long wire or fish tape to push the strap through the pipe
Step 2: Security Loop
I also made a security loop using the 3/4 EMT.
I simply bent a 90 degree angle and crushed each end to fit in my tailgate.
I just have to pass this through both ends of my security cable, close the tailgate and lock it with the car key.
Saves having to carry another lock key or remember another combination.