Step 1: Find Balance Point & Drill Seat Post Hole

Find Balance Point

Sit on the bike with the back brake on, front wheel on a chair and leaning against a wall. Keep adding spacers under the front wheel until you reach your balance point, for me it was two reams of paper.

Measure

Hold the PVC pipe in place with tape, rubber bands, or bungee cords. Mark where to make the seat post hole so that the tail of the pipe will be a few inches longer than needed, you can always cut it shorter later.

Drill Seat Post Hole

A drill press is recommended for this step, it is difficult to drill a hole at an angle through plastic with a hand drill. Use a bevel gauge to measure the angle of the seat post to the pvc pipe. Set the drill press to the same angle. Drill the hole. Use a rasp bit or file to adjust the hole until the seat post will fit snugly through it.

Tip: practice drilling the seat post hole in the front of the pipe, it will not be used.

Step 2: Pipe Cut Front & Final Assembly

Cut Pipe to Fit Front

Cut the pipe at an angle where it will meet the head tube so it won't rub on the headset, making it ~1/2" longer than necessary. I drilled an angled hole with the 1" paddle bit then used small one-hand bolt cutters to slowly trim it bigger until the seat post hole lined up. If I had to do it again I think I would skip the hole and just use the bolt cutters to trim until it fits.

Final Assembly

Use a zip tie in front and one in the back to hold it in place. Press fit (don't glue) a 45 degree union scuff guard on the end and go for a test ride! If it's too long just trim the end.

Caster?

My original plan was to mount a caster on the 45 degree union but decided it would look ridiculous. The scuff guard is holding up well so far, and they are only $2.