Smaug (or anybody that knows the answer)... With the Pace 500.2 with cadence sensor (or a 350.2), do you know if the amount of torque from the motor varies with the speed at which you're pedaling, for a given PAS level?
No, it will not vary. It will give as much torque as possible to get you up to the speed associated with that PAS setting.
If you want it to vary, you need torque sensing.
Let me explain in more detail. When I test rode the 350.2, I could have sworn that once I was ghost pedaling, the amount of motor contribution didn't depend at all on how fast I was ghost pedaling. It seemed like once the motor was On, it would stay on at a consistent contribution unless I stopped pedaling completely, and try to achieve the top speed of the particular PAS level setting (which I mostly kept at 1 that day), even if I ghost pedaled at a crawl pace. It was one of the things I didn't care for compared to the 500.3 I test rode on the same day which was awesome.
But.....I just read the following two statements off of Aventon's website where it describes cadence sensors, which makes me think maybe my impressions of the test ride on the 350.2 were wrong. I copied the following directly from Aventon's website in the description of cadence sensors. I've changed the key sentences to red. I interpret this to mean that if you were ghost pedaling at two different speeds within the same PAS level, you would get two different motor contributions.
From Aventon website:
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"The amount of effort a rider puts into pedaling and the selected pedal assist level will influence the amount of power the motor contributes. On cadence-based pedal assist systems, manufacturers typically have predetermined and preset speeds per each level of pedal assist. As a rider’s pedal cadence increases, the motor will continue to output until it reaches that predefined threshold, maintaining it as necessary amid varying terrains, gear levels, and the rider’s ongoing pedal cadence.
Key takeaways:
- As the rider’s pedaling speed (i.e. their cadence) increases, the pedal-assist will increase the motor’s output (i.e. power contribution).
- As a rider’s pedaling speed decreases, PAS will decrease the motor’s output to propel the rider forward.
It's true in the sense that it takes more power to maintain 20 mph than 10 mph, but it's not proportional to the power you put in, unless you have a torque sensor.
Torque and power are related, but are not the same thing. Torque is pure force, power includes torque AND speed.
The bottom line is that bikes with torque sensing are going to be more efficient, unless you really think about what you're doing. For example, on a cadence sensor only bike, set your PAS to a speed just below where you want to be, then use your pedal power to get that last bit.
There's no way to save the money from a torque sensor and get that natural feeling, which I think is what you're getting at. You always have to think about what you're doing to get good efficiency. You're enough of a thinker that you wouldn't have a problem with it, I can already tell that. Your son? I don't know.
Here's another example:
I set my cadence sensing bike to PAS2, which is about 12 mph. As soon as I get a revolution or two into pedaling, the motor will input maximum power to get me to 12 mph. Better programmed bikes will do this more gradually, but it's not going to depend on your pedaling torque. It uses a lot of power this way. Once you get to the gear and torque you need to actually exceed that 12 mph, the electric system won't be doing anything; it will just kick in automatically when you would have gotten below that speed associated with the PAS setting, like when you hit a hill or headwind that would normally knock you below 12 mph on a purely mechanical bike.
At the faster speeds, let's say 25 mph, you may not be able to produce enough torque of your own to go that fast, so the bike will contribute as much as possible to keep you at that speed. Your own energy will supplement the motor's, so you'll save power that way, but you'll find that the bike is doing most of the work and your battery will drain QUICKLY. Sometimes, you'll be OK with that and sometimes you'll be trying to hyper-mile it. (depending on your personality and your mission for the day)
There are a lot of very lazy riders who really just want a powered bike without having to license and insure it and they will just use throttle.
There are mostly lazy riders who will go through the pedaling motion, but will let the bike do most of the work anyway.
There are less lazy riders who want to go fast, but will put more effort in. They still want exercise, but they also don't want their speed to be so dependent upon wind and hills as on a purely mechanical bike.
Then, there are the LEAST lazy riders who will do most of the work, but just let the electric kick in for help with hills and winds, to keep moving.
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Now, if I may say so, it's time to exit the Analysis Paralysis phase and just
buy something. (unless you're saving your pennies at the moment ;-) )