Step 1: Gather What You Will Need
You will need:
Some two by fours (these will be supports but you can use other things instead I just went with some two by fours I had)
Various size drill bits
A reciprocating saw with a wood blade
An impact (optional)
A circular saw (optional)
Step 2: Prep the Pallet
Start by deciding which pallet side you want to use. Pick the one with the least broken boards. You can always swap out boards between the sides to make one good side if you need to. Cut one side then flip it and cut the other. Now is a good time to cut your two by fours to length since you already sawing. I cut mine to 26 inches because this is what would work well for my bikes and a wide variety of bikes but adjust it to your bikes.
Step 3: Add Supports
You will want to space your supports out every other board on the pallet. I have supports in boards 1, 3, 5, and 7 on the pallet. Pick a spot in the pallet where you want the tire supports to go in. I picked about 3/4ths of the way up. To insert your supports you will want to take the two by four and stick it on the spot you want on the pallet and trace around it with your marker. One you have it traced take a drill with a large drill bit and drill all four corners out. After you have done this grab your reciprocating saw and insert it in one of the holes and saw to the other drilled hole and keep sawing till you have a slot the size of your support. Insert the two by four into the hole and carefully flip the pallet on its side so you have access to the bottom of that pallet. Now put some screws through the bottom of the pallet up into the two by fours to secure it. Repeat this till you have all your supports in.
Step 4: Add Your Bikes
You are now done with the bike rack and can add your bikes. With this design you can add up to 6 bikes because bikes can go on either side. It is a little bit cramped with 6 but it is possible to do so. The great thing about this design is you have access to all sides of the bike making repairs much easier. Please comment any questions or tips you have. I did not do the best job on my cuts but I just wanted something functional. You could also paint it to make it look a little nicer