Crystalyte son Direct Drive por lo que los tacho de la lista.
Me queda el BMC que sí es "Geared" o con engranajes y creo que es el único que dá PAR a bajas vueltas. Ahora a ver si investigo lo del modelo "PUMA" y lo más importante de cuantos € estamos hablando para el caprichito del niño...
Pego una descripción que he encontrado en http://electric-bikes.com/bikes/kits.html#BMC
BMC Hub Motor Kits
BMC (Brushless Motor Corp.) offers light-weight (9 lbs.), brushless, planetary-geared hub motors that are reliable, quiet, efficient, high-torque and affordable.
Motors use internal planetary-gearing to provide torque rivaling 1000W gearless motors.
Hall-effect throttle includes power-on indicator.
No-drag freewheeling and better torque combine for more efficiency and longer range.
Additional options include choice of front or rear hub motor, controller power and voltage, battery type and size, wheel size, and flat-tire protection.
This hub wheel is built in-house to desired sizes of 16", 20", 24", 26", and 700c by Electro Ride™ LLC. The wheel build features high quality spokes and a durable spoke pattern often seen in touring bikes carrying 200 lbs of cargo. For added protection from flat tires, you can request thorn resistant tubes or Kevlar tires.
BMC V1 is a geared, brushless hub motor that handles 400 watts or more continuously.
BMC V2 is a high power, high torque brushless hub motor that handles 600 watts or more continuously. Due to larger gauge windings and more durable internal gear assembly, the V2 series is able to handle much more power and deliver speeds up to about 30+ mph.
BMC V3 is a high power, high torque brushless hub motor that handles 1000 watts continuously - enough for very high speeds (30+ mph) on relatively level terrain.
All are disc-brake compatible with a 6-bolt disc mount screw pattern on the left side.
Controllers - Various controllers work with 36V, 48V, and 72V battery packs to provide varying levels of performance.