Hello Wynne,
and am I right in thinking changing gears on a Woosh with crank drive when under load is a knack.
Yes, you are correct. As the motor drives the chain, and the chain needs a little slack when you change gear, the motor needs to stop momentarily at the same time you allow that slack. If the chain does not get this slack, it makes a little crunch noise when stepping from one sprocket to another.
You normally do that by slowing down instinctively when changing gear anyway.
On the crank drive bikes, the controllers are programmed to respond to the instinctive slowing of pedaling by quickly reducing the power, and consequently, the gear change noise.
You would expect that these crunching gear change noises would reduce the life of the sprockets and chain. In reality, nobody has reported any problem with gear change since we sold the first Santana CD in 2014. My guess is that:
1. Most frequently used gears are the high to middle, 7, 6, 5 and 4. Their ratios are close and the chain glides easily between those.
2. The instinctive slowing down pedaling before changing gear is sufficient to allow the chain to slack.
The trick we put in the Santana manual is this: blip one of the brake levers (usually the left lever) just before changing gear. If you ride on throttle, the motor cuts out automatically when you change gear, there is no need to blip the brake lever.
The Santana CD is one of our most successful bikes to date.