Fitting a motor to a bicycle, rider and terrain

Mike leroy

Active Member
Do you want the motor to behave like a turbo-charger(throttle) or cruise control? I would like to use power assist to function like a transmission. Match torque to RPM.

My main route is 2700m or 1.7 miles and 600 foot elevation change. My trip is entirely up or down a canyon, not rolling hills:
  1. 10% grade for 400m
  2. 02% grade for 400m - power unnecessary.
  3. 18% grade for 250m
  4. 10% grade for 200m
  5. 05% grade for 500m
  6. 02% grade for 1000m - power unnecessary.
To my way of thinking, throttles are better than pedal-only systems. At the very least, a throttle enables you to optimize the tradeoff between speed and battery consumption to find the best balance.
  • would configuring PALs to hill steepness optimize the entire power system, rather than just battery consumption?
  • Is it wasteful to use power assist in a high gear?
  • Why should power levels be any different than matching gears to hill steepness?
  • Should Pedal Assist Levels (PAL) correspond to each gear?

This approach requires buying the Bike and BBS02 from a local shop, on the same day. Make a return trip to customize the PAL settings. I do not see how this can be accomplished from Internet purchases, because you will not know required wattage before ordering the BBS02.

A power meter will indicate which column in the above table corresponds with your leg strength.

The folks at Cycle Analyst sent this helpful link for power meters. Many options exist according to his article:

"These units don’t actually measure your work effort using strain gauges, but instead rely upon other environmental factors. Thus the name of non-Direct Force Power Meters (DFPM).

PowerCal: The PowerTap PowerCal (offered in both ANT+ and Bluetooth Smart) is a heart-rate strap that also transmits power information. It monitors your heart rate and then uses the rate of change to determine power. While many hard-core power meter users are afraid to even glance at the thing, I found that when you started looking at real-world data, it wasn’t actually all that bad. And in fact, it was far more accurate than you’d expect. In general, I’d recommend this for someone that may be buying a heart rate strap anyway and is interested in power (since you’re basically just spending $50 more, it’s about $99 these days).

iBike: I haven’t tested out the iBike in a few years now. "

Another article using a runners power watch.
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Mike leroy

Active Member
Found this on endless-sphere.

"I am curious how the PAS Levels are programmed, and if they could be "fine-tuned" by your software...

I have tested the 5 PAS settings and I am coming up with the following results:

PAS Level 1 - Max of 220W assist
PAS Level 2 - Max of 776W assist
PAS Level 3 - Max of 1022W assist
PAS Level 4 - Max of 1022W Assist (No difference from Level 3)
PAS Level 5 - Max of 1156W Assist (25.3A/Max Possible Current)

There seems to be a pretty big range gap between PAS Levels 1 & 2.

Can the PAS Levels be programmed to output a specific max current at a given setting?

For example, could the 5-level PAS be programmed for:

Level 1: 5A Max
Level 2: 10A Max
Level 3: 15A Max
Level 4: 20A Max
Level 5: 25A Max

and could the 9-level PAS be programmed for:

Level 1: 5A Max
Level 2: 7.5A Max
Level 3: 10A Max
Level 4: 12.5A Max
Level 5: 15A Max
Level 6: 17.5A Max
Level 7: 20A Max
Level 8: 22.5A Max
Level 9: 25A Max

In my opinion, this would nearly perfect the PAS System."

Mike leroy

Active Member
    • Throttle Only Operation with pedal assist (PAS) turned off (Set to "0")
    • Default setting of PAS "0" when the system is turned on to prevent accidental unintended motor operation
    • 5 levels (we can program up to 9) of PAS with max setting at 100% of motor power (factory is 3 settings with max at 47%)
    • Engaging the throttle delivers 100% of motor power in all PAS modes (throttle overrides PAS when used)
    • Increased throttle response by decreasing the factory ramp-up setting and eliminating factory throttle delay
    • User configurable speed limiter up to 32mph (50km/h) - adjustable in 1mph increments from 10-32mph
    • Improved brake levers for mechanical (Cable Actuated) brakes
    • New Universal Brake Sensors that allows you to keep your existing mechanical or hydraulic brake levers
    • Higher quality half twist and new left hand specific thumb throttles
    • Secure 4 pin battery connector vs bullet connectors
    • Hardware for using the Drive system on a 73mm wide bottom bracket shell
    • The Mid Drive Kits are designed to fit bikes with a 68mm (2.68 in.) or 73mm (2.87 in.) wide bottom bracket shell and 35mm inside diameter. This encompasses the vast majority of bikes excluding some newer high end bikes with an Integrated Bottom Bracket, and Fat tire Bikes with a 100mm wide bottom bracket shell.