Matthew Slinn may be an engineer who knows about batteries, but his bicycle knowledge is lacking. To quote from his book, "In a wet environment, rim brakes will be next to useless". I guess in the entire history of the Tour de France, none of the racers have been able to stop their bikes in the rain because they never use disc brakes.
He claims that your maximum speed on a bike with 20-inch wheels, a "60T cog on the front" and a "12T cog on the back" is 20mph. Thus, one could conclude that the maximum cadence (pedal rpm) is 66. That's the cadence of a beginning bike rider, not experienced cyclists who are more likely to ride at a cadence of 80-100. He also claims that with 26-inch wheels and the highest gearing, the maximum speed is 30mph. Tell that to Mark Cavendish whose sprints are closer to 50mph than 30mph.
His knowledge of folding bikes is pathetic. "Smaller wheels reduce ride stability." "The folding bicycle is not a stable platform for high speed performance, so you should select [electrical] components for a maximum speed of 20 mph." Tell that to owners of Bike Fridays (I'm one of them) who ride their folding bikes at speeds of over 40mph when cruising downhill when pedaling 1,200 miles down the west coast. To make a folding bike more stable, he states, "You can make the bicycle more stable by swapping the handlebars over from a normal bicycle." His idea of how to make a folding bike fit better: "If you are tall, then you can make the seating position bearable by extending the seat to maximum and lowering the handlebars to the minimum."
A logical flow to the narrative is totally lacking. Right after discussing brakes, he jumps to soldering. After he talks about securing batteries to the bicycle, he brings up choosing a bicycle frame.
There are many good books on bicycle wheel building. This isn't one of them. He has a picture of a rear wheel with all of the spokes on the non-cassette side of the hub coming out of the inside of the hub and all of the spokes on the other side coming out of the outside of the hub.
There is only a pair of paragraphs which talk about electric motors driving a chain. The rest of the book focuses solely on hub motors. If you want to know about batteries, capacitors, and hub motors, this is the book for you. If you want to have a working electric bicycle, look elsewhere.
