I'm a bicycle mechanic looking to install a mid drive motor on my Kona Ute cargo bicycle. I've done some research and *think* I would like a double freewheel motor as the wheelbase and drivetrain is long enough for one between the rear wheel and crankset without crank clearance issues.
So far all I've found is the Cyclone mid drive double freewheel motor. My googling has led me to again *think* that I would like to buy a battery from Ping battery rather than one packaged with the Cyclone motor kits? Possibly even finding a motor/gearbox/controller from a US based vendor as opposed to ordering from Taiwan?
My goal is as follows:
7 mile commute to the bike shop, lightly loaded (usually less than 40lbs in the pannier bag). Bike weighs 40ish, I weigh 170ish.
I'd like to average 25mph which I figure will require a 35mph top speed (more is ok, 40 max though). 25mph would get me to shop in 17 min.
Hills are non existent other than one elevated pedestrian freeway crossing.
Battery range should be 15 miles minimum, would prefer 25mi.
Minimal pedal assist, mostly just to get moving from a stop. I prefer to get my workout from other bicycle rides.
How does Cyclone determine "top speed"? I'm looking at their 960w motor which claims 60kmh(38mph-ish) and wonder how they arrive at that claim? I see some RPM specs in the 3-4K's but I assume that is the motor shaft, not the gearbox shaft? My calculations with a 14T freewheel driving an 11T cog on the rear cassette would mean the gearbox shaft would need to turn 350-375ish RPM?
I see lots of posts about RC motors here. Being a bicycle mechanic I'm very DIY and would be open to a DIY solution. My budget is about $1,200 not including another $150 for a CycleAnalyst computer (are these worth the $?). I'm also a welder with a big drill press so I can make motor mounts, drill big holes, but cannot machine parts.
Is there a good primer on mid drive motors that someone on the board has written? Is there anyone willing to assist me with putting together a DIY solution for a small fee or in exchange for bicycle parts?