I recently purchased a short bed truck with a cross-bed toolbox and was faced with the dilemma of how to transport my bicycles. I thought about bolting fork mounts to the top of the toolbox but quickly dismissed the idea because it wouldn't work with the disc brakes on my mountain bike. Besides, I did not like the idea of drilling holes in the top of the toolbox. With my previous truck I had a piece of 2"x4" lumber with fork mounts bolted to it, that I set in the bed. I decided to try to figure out a way to attach the 2x4 to the top of the toolbox. The lid of the toolbox has a lip on the sides and back of the box and a continuous hinge across the front. The front of the bed of the truck has a lip between the bed and the cab. At first I thought of getting a longer 2x4 and using some J-bolts to attach it to the side lip of the toolbox. But then I remembered "The Donor".
Step 1: The Donor
The Donor was an inexpensive trunk mount bicycle rack that I had not used for years. It attached to the car with flat metal hooks attached to the bike rack with webbed strapping. I tried the hooks on the lip of the toolbox and found that they fit well. I disassembled the bike rack to remove the hooks and straps.
Step 2: Bolt the Fork Mounts and Straps to the 2x4
To construct this bile rack you will need a 2x4 that will easily fit in the bottom of your toolbox. I used one that was about four feet long. You will need bolt-on bicycle fork mounts with bolts, nuts and washers that are long enough to bolt the fork mounts to the 2x4. You will also need two webbing straps with four flat metal hooks and four strap tighteners. If you don't have an old bike rack laying around, you might be able to find one at a thrift shop, a garage sale or on Craigslist. Auto parts, hardware or sporting goods stores might have just straps and hooks.
If you want to paint the 2x4, now is the time to do it.
The fork mounts should be positioned at the edge of the 2x4 for disc brake clearance as shown in the second picture. The distance between fork mounts should be the width of the widest handlebars of a bike that will be attached to the rack, plus a couple inches. Mark and drill holes for the bolts for the fork mounts. Position the center of one of straps between the bolts for one of the mounts. Bolt the mount down, clamping the strap under it. Repeat with the other strap and fork mount.
Step 3: Attach to the Toolbox
On my truck, the toolbox has a continuous front hinge so I hooked the front straps to the bed rail lip as shown in the first picture. Other truck/toolbox combinations may require different attachment points.
The back straps attach to the rear lip of the toolbox. Center the 2x4 side to side and towards the front of the toolbox lid. Tighten the straps.
Step 4: Attach the Bike
Attach the bike to one of the fork mounts and check disc brake clearance. Try closing the truck tailgate. If it doesn't quite close, move the rack forward, tighten it down and try again.
Step 5: Store the Rack
One of the benefits of this rack is that when you don't need it, it stores nicely in the toolbox.
Enjoy your new rack!