Who's got two thumbs, and finally got his BMS from China?

This person! ->

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Progress has been slow, so I've been looking at other stuff I haven't paid much attention to yet. I've been asked a couple times about gear ratios and torque. That sort of thing. Problem is, I don't know much about that stuff, and what I've seen on the internet is rather confusing. I can though, leave you all with some measurements, and those that are interested can maybe enlighten me on how it all works.

I measured my 26" wheel, and found out that the wheel with the tire on it is actually 26" in Diameter.

The sprocket fixed to the wheel is 7" in Diameter, 44 teeth.

The freewheel cartridge attached to the motor is 2.5" in Diameter, 14 teeth.

I figure an average speed of 10 mph would be nice. Maybe a little slower going up hills. The idea is that I will be pedaling as much as I can, and the motor will be the assist, rather than the other way around. (This is for me to get a little more fresh air and exercise after all.

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I searched for quite a while, but could only find vague remarks about how much torque a car starter motor typically has. I found 1 reference that suggested a typical starter motor might be around 24 Nm. Another site,

what-when-how.com, said a 4-cylinder engine needs 8 Nm / L. Which for a 3L engine as my motor is designed for, would work out to 24 Nm. Converted to ft-lbs, that would be 17.7. Kind of nice that the two websites agree, but I sure would have liked to find a torque vs RPM chart.

As for how much power is needed to get me up a hill, well, I don't know how to translate torque into whatever that would be. Horsepower? After a while I just gave up and searched for ebike calculators:

http://www.kreuzotter.de/english/espeed.htmThis one calculates man-power in Watts, but is not actually for ebikes.

https://electricscooterparts.com/motorwheelgearratio.html This one is more for wheel ratios and RPM

I also just downloaded an "Inclinometer" app for my cell phone. Hopefully I'll be able to use it to find out the grade of all these hills I keep complaining about, LOL.

So far, I've learned that a 26" diameter wheel will go about 129 RPM at 10 mph. Seems I have a 3.14:1 ratio, so the motor will be going about 406 RPM. That other website also told me that a typical engine spins at 100 RPM by a typical starter motor, and has a 10:1 ratio. That means the starter would be spinning at 1000 RPM.

I've also heard that permanent magnet, brushed motors have more torque as the go slower. So hopefully I'll have more that 17.7 ft-lbs at my 406 RPM. Will that get me up the hill? Still don't know...