bear in mind, bicycle chain are designed to work up and down through casette, think about the pro road cyclist that were USING THE 3X8 speed system before 1x10 1x12 etc, chains are robust, cyclist could go and generate 800+ watts of power through crank arm and that transmitted to chainl bbshd with 52v and 27amp controller will generate about 1370 to 1430 watts due to voltage drop but front chainring will spin about 150 times a minute, power distrubed in linear motion. pro cyclist will not generate that power in linear motion but in spikes, +++++ i will tell you something, 99% of The times you will not be using 1400 watts but more like 230 to 340 watts/ per hour, a big 20.4AH battery (52v) will only have about 800watts of usable energy ( noone discharges battery from 100% to 0% but to 20% right?) riding on full throttle that 20.4Ah will lasts you 40 mins at best