Cycling UK Forum

E.g. if you are a luddite using a turbo trainer and want to measure your milage.
A standard computer is supposed to have a distance wheel/magnet to sensor based on fork spacing and the rear triangle (on my trike especially) is much wider.
I can solve this by taping the sensor to a die and then taping both onto the rear triangle, but it is neither elegant nor permanent. What do youse do?

This may not be relevant but my memory of trying to use a computer on the rear wheel* was that the cable isn't long enough if you want to read it on, say, the handlebars.

* I can't for the life of me remember why I wanted to do that either.

I just stuck mine where it worked. Stick the wheel magnet on and hold the sensor whilst moving the wheel.It will probably go nicely on the frame somewhere.

Decathlon have (or had) a wireless one where the sensor is wrapped around a hub, front or rear, no magnet. Use one on the turbo trainer and on the road with no need for changing the sender nor the receiver.

I use a Cateye Strada Cadence computer on my turbo trainer bike (an old mountain bike I converted to dropped handlebars, racing saddle and turbo specific rear tyre). The dual cable runs from the computer, mounted on the top of the handlebars, down the downtube, under the bottom bracket and onto the chain stay. There it splits into two and goes to two separate sensors, one near the bottom bracket and the other nearer to the rear wheel dropout. These two sensors work in conjunction with two magnets, one on the pedal crank arm (to measure cadence) and the other on the rear wheel spokes (to measure speed, distance, etc). There was plenty of cable to do this. If you do not get a cadence measuring computer then the cable is probably only going to be long enough to work from the front wheel. Your alternative would be to go wireless.

Hi,
When I used to do this I used to fix the Speedo if it was a wired one onto the turbo itself.
To be honest speedos are so cheap you can easily have a separate one on the turbo and leave the other one on the bike handlebars.
Sensor goes on the chain stay, as it is very similar to the front forks tube.

If you have a satnav with BT sensors, then just buy a speed and cadence combined sensor and mount that on the chain stay.

I had a speed/cadence sensor with my Garmin, since sold. That was self-calibrated.

Also, some years later, have used a wireless Cateye thingy. Needed a magnet and to be calibrated for wheel circumference, and would fit on front or rear wheel. I used it on the rollers, but it would be fine on a turbo.

If you use an Ant+ or Bluetooth wireless computer you can get a rear wheel sensor/transmitter, usually combined with a cadence sensor.

I just chopped the cable, soldered an extension piece in, put electrical tape over the join and attached the magnet to the real wheel and sensor to the chain stay. Worked fine for a turbo trainer.