The motor in my electric-assist kit on my recumbent has developed an annoying knocking sound. This is not something I could fix, nor could my dealer, it would have to go back to the factory (in China) to get refurbished. It took me a while to isolate it, but I finally got it to go away by removing the wheel and remounting the original wheel (with no motor). This is the second time one of these add-on kits has had serious issues, so I decided not to throw good money after bad and just restore the bike to non-assist.

This leaves me without an electric-assist bike. I like to have one to extend my range and ride with groups that would otherwise be hard to keep up with. I’ve had enough fun with the add-on kits so I decided to treat myself to a factory-built electric assist bike from my local bike shop (with the added bonus that they can work on it if something goes wrong- they would not touch my add-on kits). I was planning on treating myself to a “dream bike” next January for my 70th birthday, but events moved the timetable up. I’ll put a bow on the bike next January to remind me. Quality factory-built e-bikes are expensive, but are still an economical (and green) option if they replace a car.

New bike, a Specialized Vado SL (sorry about the messy garage)

The new bike replaced my 9-year-old Trek hybrid. I donated the Trek to Mike’s Bikes which has a really cool “Bikes for Africa” program. They help train people to repair bikes in Africa, then provide them with donated bikes for the local community. My old Trek will make someone happy because it is fairly lightweight, very solid, has a good suspension, and has good tires.

The recumbent will now be a shorter-range bike for easy days. I can still readily go for hours on it if I want, I just won’t cover as much ground. And there’s a plus side to that. Some of the longer rides I used to do took me to territory with bad pavement, such as the Northern part of the Coyote Creek trail, which has a lot of places where tree roots have buckled the pavement, making for a bouncy ride on a recumbent.

I took the new Vado for a 2 ½ hour shakedown yesterday, and it was superb. The assist is much smoother and more natural feeling than one of the kits, because of torque sensing instead of cadence which I explain below. Because of a design trade-off to make it lighter weight, this bike theoretically has a much weaker motor than my previous kits, but it gave me plenty of assist. I was easily able to cruise at 28 mph on the flat and climb a local challenging hill (Bernal road to the IBM Research gate) in “eco” mode, the lowest setting. On Saturday, I’ll give the new bike a bigger challenge on a longer group ride.

After climbing the big hill, looking towards Coyote Peak in Santa Teresa Park
Looking Northwest towards the Santa Cruz Mountains. IBM Almaden Research Center is just beyond the grassy hill in the foreground to the right.

Electric Bike 101

Electric bikes either have a throttle, which allows you to ride it like a scooter, or electric assist, where the motor only kicks in while you are pedaling. Some have both. For electric assist, the system can use a cadence sensor, which senses when you are pedaling. This is on-off assistance, off if you are not pedaling, and on if you are. You control the amount of assist by adjusting the level on a controller. This is usually the set-up on less-expensive systems, like the two kits I had. A better approach is to use a torque sensor, from which the system can tell how much effort you are putting in, and match the assistance to a certain percentage of that. This feels much smoother.



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