Sigma Bicycle Speedometer Installation

My Sigma BC 906 bicycle speedometer came in today, so I got started installing it.

It comes setup to mount to the handlebars using double-sided tape and an overgrown rubber band.

I tried it, minus the tape, and it wasn't very sturdy. I decided to make a bracket to mount it to the master cylinder. I started by removing the 4 screws that held the handlebar mount to the rest of the unit.

Then I drew out a design on some old 16 gauge steel that I had lying around and cut it out.

I cleaned the metal off and drilled hoes to mount the bracket to both the Sigma and the master cylinder.

I painted the bracket flat black, then mounted the gauge and the bracket. You can see that I screwed up and cut one corner off too far, so I would only be able to use 7 bolts to mount the Sigma to the bracket. It only used 4 originally. It didn't matter, becaues I couldn't find any screws that small in my screw collection. 4 will do for now.

I pulled off the front fender to allow access to a bracket on the shock. To test some ideas out.

After deciding how I wanted to set it up, I used JB Weld to attach the magnet to the wheel and let it set up overnight.

I don't really like the way it looks too much. I kind of wish I had picked up a different style of magnet for the wheel. The flat round magnets that some speedometers use seem a bit tougher and look a little better set up this way. Here's a pic of one of the magnets I used on another bike of mine.

I made a steel bracket to mount the pickup to with a slight bend to make it run parallel with the magnet on the wheel's lip.

I pulled the stock foam from the rear of the pickup and replaced it with 3M double sided tape. Then I stuck the pickup to the bracket.

I decided to leave my fender off, so I just used the stock fender bracket bolt to mount the pickup to the shock. If you wanted to retain the fender you would just need a longer M6x1.0 bolt and nut to mount the bracket.

I secured the pickup wire with wire ties and then set the tire size to 1,473 as suggested to me for a 120/70P12. After a few tries, I ended up at 1,468 to make the speedometer read the same as radar.