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FAQ: Direct Drive Hub, Geared Hub and Mid drive

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    FAQ: Direct Drive Hub, Geared Hub and Mid drive


    Guide to selecting a motor

    What is a direct drive motor (Called DD):

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    • This motor was the first motor mass produced for a bicycle and was created to be simple enough to be installed by anybody. Just remove your wheel and replace with the DD kit wheel.
    • Instead of using the bicycle drivetrain, the direct drive bypasses everything so no stress on the chain and rings/cogs.
    • Inside the hub, there is a BLDC motor (Brush Less Direct Current) like all the other types of Ebike motors we have here.
    • The hub is attached to a rim using tradition spokes (or sometimes heavy duty spokes).
    • Can be used in the front fork or on the rear dropouts, measure your dropouts before ordering!






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    • Motors likes to spin very fast but hub motors do not have gears inside so they are less efficient at low speeds (And they can bog down at low speed)
    • DD's are heavy and they put the weight in the front and/or the back which is not the most desired spot
    • Creates unsprung weight, they are heavy and suspensions have to deal with high inertia
    • Can be used to recharge the battery when braking (called REGEN)
    • The magnetic field adds resistance when coasting, there is no freewheel inside
    • Cannot use a internal geared hub transmission if the DD hub is on the back wheel
    • Difficult to change a flat tire
    • Quiet, simple and very reliable.
    • Easy to use, always ready to go, pedal along with the motor and never need to bother with changing gears to get the best motor cadence (RPM)








    List of Luna Cycle Direct Drive Hubs, click on them!

    The Golden Motor Magic Pie 5 Vector
    The Golden Motor Smart Pie 5 Vector

    Fat Ebike Kit 1000 watt
    Ebike Kit 1000 watt




    What is a geared hub motor:
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    • The second type of hub motor is the geared type, they use gears inside (usually a planetary gear design) to reduce the size and get higher output.
    • Is fitted to the bike the same way as the DD motor
    • Creates the same weight imbalance as the DD motor
    • Difficult to change a flat tire.
    • Uses a smaller BLDC motor
    • The gears help you get more torque, better starting capability and better climbing abilities
    • Smaller and lighter to achieve the same power level as the DD
    • Produces friction and gears can wear out with abuse
    • Freewheel design means minimal resistance when coating (no drag)
    • Even with gears it is still very reliable
    • Not all geared drives can do regen






    List of Luna Cycle geared Drive Hubs, click on them!

    Mac ASI Sinewave kit
    Geared Hub motor kit 1000W

    Bafang 750W Fat geared front hub motor kit
    Double gear / double torque motor





    What is a mid drive:

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    • The mid-drive is like having superman legs, it's a motor linked to front chain ring.
    • Uses the bike gearing so you can always transmit the full potential of the motor to the ground using the right gear. Just like a car or a motorcycle.
    • Best weight placement, low to the ground and well centered. no unsprung weight.
    • The best climbing motor available, best torque delivery
    • Uses a BLDC motor
    • Pedal assit (PAS) is built in most unit (like the bafang, Shimano Steps, Yamaha and Bosh mid drives)
    • Puts less stress on the dropouts and/or fork compared to hub motors
    • Can be used with IGH (internal gear hub transmission) like the mythical Rohloff
    • Not all bikes (but most) are compatible
    • Not as easy to install compared to a hub motor, need specific tools
    • Can eat up chains, cassettes, derailleurs and chain ring if not tuned properly and if improper use of the gear changing system. (Use a gear sensor to cut the power between shifting)
    • Can replace a flat like a normal bike
    • Better efficiency
    • Often nosier than DD hub (Bafang's mid drives are still extremely quiet)
    • More expensive per watt than hub motors






    In summary, it's about what you do with the bike that will point you to the right motor. The geared hub and mid-drives will give you better efficiency, lower weight and better climbing capability. Mid drives are a god send for mountain and single trail ride and they perform very well at commuting in the city. And direct drives offer more speed, regen capability, higher reliability and a quieter ride.

    For me and most of the Luna crew, mid drives have a special place in our hearts :)


    List of Mid-drive kits available at Luna, click on them!

    BBSHD KIT 1000W
    BBS02 KIT 750W
    Cyclone Kit 3000W
    Cyclone Mini KIT 2000W
    Cyclone Monster XL KIT 7500W





    To learn more about motors click here
    Last edited by Sebz; 04-05-2017, 06:05 AM.

    #2
    Nice comprehensive writeup.

    I can confirm that flat tires are more difficult to change with a DD motor in the rear. I have to undo 7 electrical connectors and 11 nuts to remove my rear wheel.

    Comment


      #3
      Whenever I change a flat, my wife tells me there's a loose nut behind the wheel...

      Comment


      • Sebz
        Sebz commented
        Editing a comment
        hahahahaha
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