A relatively inexpensive but good looking wall mount for a bicycle, easy to construct with relatively few tools and about £30 of material. (laser cut facias optional.) The mounts are removable for when the bikes are not on the wall, meaning you are less likely to walk into them.
Step 1: Cut Your Pipe.
Start by cutting two lengths of 25mm diameter pipe, long enough that your bike will be able to rest the inside of the wheel rim on it and still be far enough from the wall to hang straight. I did mine 350mm which is plenty for a cyclocross bike or a mountain bike. Narrower pipes may work though I'd be concerned about them cutting in to the plywood from the pressure generated by the weight of the bike.
Step 2: Create the Metal Sockets.
Cut two 45mm length pieces of 32mm diameter pipe. You're looking for a nice snug fit around the pipe you used for the longer pieces. This pipe had a 3mm wall thickness, so it's pretty sturdy stuff, probably a bit over the top.
Step 3: Cut the Plywood Blocks.
Create four 150mm X 100mm rectangles of plywood. What's important here is that you get a good thickness of wood. I used 19mm plywood and doubled up to give just under 40mm. Cut a 32mm hole in each one 3/4 of the way down the centreline.
Step 4: Assemble the Mounts.
Hammer the short 32mm pipe section into the hole on one of the boards, apply glue to the top of the other piece and hammer the pipe all the way through that too. Tighten it all up in a vice to dry.
Step 5: Drill Pilot Holes and Test Fit.
Drill some pilot holes near the top of the blocks. I also drilled a third hole in the centre, in which I inserted a small section of dowel to help locate and affix the acrylic facia plates.
Step 6: (Optional) Acrylic Facia and End Caps.
Laser cut some acrylic to create two plates with holes for the socket tube and dowel. Cut 4 rings with internal diameter 33mm and outer diameter of 39mm. Cut 4 circles, 39mm in diameter. Glue two of each in a stack to create an end cap for your pipes.
Step 7: Attach Blocks to Wall.
You will need to use some fairly hefty screws and plugs to deal with the leverage produced by the weight of the bikes. Mount them both at your desired height taking care to keep them straight and level.
Step 8: Add the Facias, End Caps and Bike.
Now all you need to do is attach the optional facia to hide the screws, glue the cap onto one end of each of the pipes and slide the pipe into the socket. Add your bike and welcome the new floor space you created by sweeping up all the mess.