I knew from the earlier trial that I could mount the sensor on the fittings for the front brake caliper. Last time I fitted it with cable binders, but this time I used the included rubber band. The sensor is made to be fitted on a vertical fork with the included rubber band, but it can also be fitted on a horisontal stick as seen on the picture.
Last time it was mounted, I used the small bar magnet and glued it to one of the carvings/holes in the disc (the one supposed to be used on spoke wheels). Since then I've fitted a Braking front disc, and the wholes in this disc have different shape and are in different places. But along with the Sigma was also another magnet (The black one in the lower right corner of the first picture). It is supposed to be fixed with abrasive tape and/or a cable binder. But it was to thick to fit between the disc and the front fork - even without the tape. So I grindet the plastic down to the magnet. Then it can pass the fork, but there is much less than 1mm clearance. The next problem was placing it so it would'nt touch the brake caliper, but still get close enough to trigger the sensor. By lifting the front wheel so it could turn freely I could try out different positions. And after some trial and error I found the best position. I then fitted the magnet with both glue and a cable binder.
(On some of the pictures there is a smaller magnet. Its a Cat-Eye which is made for the pedal on bicycles, and can also be fitted with cable binders. Unfortunately its magnet has the wrong orientations for my sensor position, so it triggered the sensor twice when driving slowly. That is each end of the magnet triggered the sensor, while it was off when the magnet was just opposite the sensor.)
The wire from the sensor to the computer's socket was also not long enough, so I extended it with approx. half a meter. I fixated it to the brake hose with cable binders. The transition to the new cable is done close to the horn and is also fastened securely with cable binders.
I had decided that I wanted to mount the computer on the right handlebar just above the light scwitch. The socket/base for the computer is made for a round handlebar so it also had to be modified to fit the almost flat surface. It was also fixed with adhesive tape.
Then I just needed to find a route for the wire. Between the metal center and the plastic part of the handlebar is a small crack. But it was big enough to get the wire through, and from there it follows the cable from the throttle inside, and from there down trough the fairing.
The last thing remaining was then to calibrate it. I entered an approximate value, and drove 10km (measured by the poles by the road). Then calculated a new value and tried again on the same road. Then I tried a few other roads to make sure that the poles of the first road was spaced correctly. So now I have a speedo that is accurate within 1%;.
Sigma has a homepage on http://www.sigmasport.com. Their products can be bought in many bicycle shops and mailorder from i.e. Louis and Polo.
