Saturday, September 18, 2010

Fitting a Speedo

Ben isn't a huge fan of speedos, and for that reason and because he wants to see what solutions us prototypers come up with, there's no standard speedo or mount for the rotovelo. Yet.
So I've bought a Knog N.E.R.D. wireless speedo and fitted it. The basic problem is that the sensor has to be close to the spokes and also point more or less at the display. With most recumbents this is tricky, but at least with velomobiles it's easy to get the two close together. My problem is that I really want the display on my dashboard, but I can't work out how to get the sensor pointing towards the dash. So I've mounted the display behind a wheel arch. I can see the speedo when I'm riding, but it's not very easy to read. Which is not really a bad thing, it'll still tell me roughly my cruising speed, my max speed and how far I go.
I cut down one end of a bit of tubing, flattened it and drilled a hole so I could attach it to a brake mount as shown. It's padded with gaffer tape and plastic to get it closer to the spokes.
Attaching the display requires a tube to imitate the handlebars they're designed to mount to, so I used a piece of hose. The metal bit is a 10mm socket and driver holding the M6 nut in place.
RotoVelo cockpit with the speedo display on the right. Yes, the speedo is also red.
There's a bolt head in the wheel arch, and in an attempt to discourage leaks I used a washer and bit of old tube as a seal.
A random photo of Phuong.


  1. ANT+ wireless speedos are easier to use on a velo - they are 'proper' wireless and not directional, so I have a speed sensor on the rear wheel of my SLR and a cadence sensor up front. The one I've bought (Garmin Edge 500) was dearer than a stock bike computers but I didn't look at bike computers from other makers - sure I saw Knog on the list if they are your favourite.
    Hope that helps...

  2. Sounds interesting. Next time I buy one I'll know :) For now, I'll see how I go with the NERD.
    Are they all push to start? I'm used to the wired ones where you can ignore the thing until you want to know, but the NERD seems to require me to push the start buttun or it just sits there.