Your question is good, but dialing your bike in for yourself will depend on too many factors for me to even guess. In your first post you called yourself an "old" cyclist. I am old, 70, but was never a "cyclist", so you probably are happy spinning faster than I am. My IGH (Nexus Internally Geared Hub) has an 18T cog and that could be replaced with a 16T cog to give 2 or 3 more MPH, with a proportional speed increase in lower gears, but a little less torque.So with moderate/heavy pedaling you could hit 25 MPH? That is what I am shooting for with tailwind and/or slight downhill, to make up for the 6-7 MPH uphill.
I think a "16inch" motor in a 700c rim running at 36v should have a high enough no-load rpm as a hubmotor to do 25mph. By using a slightly larger sprocket on the hub than the smallest on the rear cassette, you can get a bit more speed if it isn't. I think this is the point, by mid mounting a hub motor you get more flexibility because you can change the rear cassette and the sprocket on the motor to get your gearing right. And by having the same size sprocket for both chains, you still keep the pedal chainset to rear cassette the same. I'm told the nominally 250W motors are safe to push to 15A-36V which is over 500W. That should be enough in a 'bent to reach 25mph on the flat. That matches nicely with a 36V-15AHr PingThe gearbox is on SWXK or SWXH or SWXB always the same the different speed comes from copper windings inside the motor and in this way the realise different rpm for different wheelsize. 175rpm is for 28",195rpm is for 26", 220rpm is for 24",255rpm is for 20", 275rpm is for 18" and around 320 is for 16"
Where are the freewheels in this config? Does that mean the pedals have to move under motor power?katou wrote:First stage: motor to left side Bottom Bracket cog
Second Stage: right side cog to rear cluster
I know some of the Cute & Fusin geared motors are slower rpm at higher volts. Also, cell_man had/has or can get a slower wind DD below a No load speed of 280rpm at 39.2V upon special order. He has good prices & can sell the bare motor. These geared or DD motors are low-cost, and many of these geared motors are very, very, quiet too. So, I'm thinking cost or loudness should not be an issue with geared motors.Warren wrote:The problem is that you want a hub motor wound for running 20 mph on 48 volts, in a 26" or 700c wheel. Used for a mid-drive, this gets your cadence in the normal range, with normal bicycle sprockets, and chainrings. Unfortunately, all the geared hub motors I am aware of are wound for 36 volts at 20 mph.
On the other hand, If I ran a geared hub motor on 36 volts, the lighter weight would offset the extra weight of a 36 volt, 30 amp Ping pack! Same total weight, more range....but both the hub motor and the battery pack would be more expensive.