The Grand Tour: Fife and Beyond

Ramblings of an inveterate cyclist

 If you have been following my blog you will know that a few weeks ago I converted one of my bikes, by adding an electric motor rear wheel, and all the trials and tribulations that entailed. I have been out most days, and covered a few hundred miles, on the bike since its conversion and, feel now I can give a summary of how it feels to ride.

When I was considering an electric motor for my bike, I did a lot of research on the internet, but since most of this information is supplied by companies trying to sell you something, you will possibly, like me, end up more confused than you were at the start.

The big question?

Bottom bracket torque sensor

‘Torque’ of a ‘Cadence’ sensor, (although you can now get e-bikes that come with both and a high price tag). Most kits come with a cadence sensor that is a ring that is slipped over the crankshaft at the bottom bracket. The cadence sensor detects if you are pedalling and if you are will tell the controller, (supplied with the motor) what power to transfer to the motor, (up to the limit you have set on your display) the one I have happens to have 5 settings. Along with this, there is a trigger or throttle control, this overrides the sensor and you are now riding an electric motorcycle, and depleting the battery at a fast rate of knots. You will of course still have the choice of gear already on the bike, I have found that I have never used my small front ring or granny gear since fitting the motor, mostly I will be on the middle ring and middle cog or above.

A torque sensor, on the other hand, detects how hard you are pedalling, and you have to supply around one-quarter of the power all the time, if you stop pedalling, the motor takes a break too. The controller will pass this information onto the motor, and in turn, will give you a range from economic about 50% power to 300% full power. The advantage with this system is that it rides more like a bike, but with a bit of assistance, (dependent on your input).

Sum up,

With the cadence sensor you only need to pretend to be pedalling to get full power, you can simply use the throttle. With the torque sensor, you are always helping. Even at the 300% level, you are still providing one-quarter of the power yourself.

Since I have never ridden a bike with a torque sensor I can not tell you which is best, but if you are still fairly fit and still a strong cyclist I would prefer the torque sensor bike. It would feel more like riding an ordinary bike since the motor delivers its power through your own effort at the peddles, and you will not have to fiddle with touch screens and triggers, and of course a fully charged battery would take you much further.

The cadence sensor bikes can be used at all levels, switch off the motor and you have a very heavy to push bike. Set the amount of help you wish on the screen, zilch to five and off you go, when you find a hill and the effort is becoming a strain, pull the trigger for more power, woosh off you go.

The only bike I have found that has both are the SmartMotion Pace/Catalyst which allows you to select which mode to ride. But torque sensors are very complicated, which is reflected in the price, and the main reason I suspect why all kits come with a cadence sensor, then again, if you need an e-bike conversion it is possible because, like me, you still love to cycle but are finding peddling up hills and into strong headwinds, to say the least, tiring.

Keep well and keep pedalling.

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