In February I decided to try and legalise the Pino as best I could while retaining the throttle to get the bike moving at junctions etc.
See my previous post about reprogramming the Bafang motor
Having seen several posts on Facebook where the police had seized e-bikes for having throttles that power the bike without pedaling, even if only up to 15.5mph, I thought I should try to get the Pino as close to being legal by curtailing the throttle top speed even more. Legally the throttle can only power the bike up to 6kph (3.7mph).
Now I’m in a bit of a pickle… With a throttle, I can apply power, get the bike moving and then we can start pedalling. This is possible even on a good gradient. It’s so handy that I consider the ability to accelerate the bike fairly briskly at busy junctions a safety feature. But with the throttle powering the bike up to 15.5mph we could fall victim to a zealous member of our police force.
Without any electric assist, getting the Pino moving, even on the flat, is not easy. It takes a couple of ‘scoots’ from me to get the bike moving enough for me to get my feet up onto the pedals, then we can both start pedalling and once moving, we’re ok. On any rise it becomes extremely difficult.
Whatever arrangement we have is going to be a compromise but I thought we could experiment a little so I disconnected the throttle completely but reduced the number of pedal revolutions it takes before pedal assist kicks in and increased the amount of power initially applied. We went for a 25-mile test ride to see if we could do without the throttle but a more aggressive uptake from the motor. At a junction on a slight incline, getting going proved tricky and at another junction on a blind bend we didn’t accelerate fast enough to get across the road comfortably.
So, I want to retain the throttle, limiting it’s speed to something which will still be useful when we need to pull away uphill or at a busy junction. I connected up the programming cable again, but found there’s no straightforward way to set the throttle maximum speed to 6kph – the system won’t accept it. After some searching and reading blogs and discussion groups I found a reasonable work around.
The result is that in power level ‘0’ the throttle will still have no effect, but in all other levels it will achieve 40% of that power level’s maximum speed. As the Bafang provides assistance at the chainwheel, not the hub, any assistance is amplified by higher gears on the Rohloff. In level ‘1’ the throttle will move the bike without any pedaling to only a couple of mph and in level ‘9’ it will power the bike up to about 8-9mph.
We normally pull away in gear 8 on the Rohloff and in power level ‘9’ that will power the bike up to about 6mph which should be fast enough even on a hill start.
Another test ride will see how we get on.