Torque-Speed profiles I have experimented with-
24V w/16Tmod nears 20mph nicely (lately 25.9V LiCo w/16Tmod - nicer)
29.6V wo/16T mod will give the same 20mph speed, but with substantial more torque and acceleration. (see 2nd picture)
Note - the torque line is typical for all single phase electric motors, Max amps-torque at 0mph steadily decreasing towards 0 torque-amps at max no-load rpm.
More recently I have been experimenting with optimizing towards the "legal" 20mph.
Note - The Blue torque line bends at the point that the controller is providing less than usable amps.
29.6V system could use ~50A at 0 mph-rpm, 35A controller could be replaced with more powerful ... would give slightly better torque below 12mph and a worse efficiency % ...
60A controller vs 20A controller on same motor Torque and watt output lines vary sharply but top speed remains identical.
This simulator offers much information, including the watts of energy required to maintain any speed, for example, for a typical mountain bike:
5mph requires - 22 watts
10mph requires - 68 watts
15mph requires - 163 watts
20mph requires - 333 watts
Yes! 15mph requires 2x the power as 10mph.
20mph requires 2x the power as 15mph.
20mph requires 4x the power as 10mph.
30mph requires approximately 1000 watts, not electric watts input, motor watts output.
Wind resistance is a *****!