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Enormously useful yet surprisingly small—the Tern HSD S+ folding electric bike is shorter than a standard bicycle, yet carries a whole lot of cargo, while offering a ride so easy, it shifts itself.

  • Features

    • Next-generation Bosch® Performance Line motor with Intuvia display delivers pedal assist up to 20 mph, helping you carry groceries and tackle steep hills, without the sweat
    • enviolo AUTOMATiQ shifter and Sport 380 internally geared rear hub offer effortless, stepless automatic shifting across a wide gear ratio range of 380%
    • Perfect for longer rides, the Bosch PowerPack 500 battery offers a range of up to 74 mi., depending on conditions and assist settings
    • Custom Suntour suspension fork smooths out rough roads with 70mm of travel
    • Cane Creek® Thudbuster ST suspension seatpost offers additional comfort without sacrificing performance or control; tunable to match your weight and riding preferences
    • Magura® MT4 hydraulic disc brakes deliver consistent, powerful braking, even in wet conditions
    • Gates Carbon Drive® CDX belt lasts more than twice as long as a typical chain and works without lubrication, meaning no greasy, dirty buildup to get on your hands or clothes
    • ABUS® keyed-alike frame lock offers light security for quick stops and can be matched to use the same keys as a higher-security ABUS lock (not included)
    • Fits riders from 4'11" to 6'5" (150 to 195 cm)
    • Fits one Thule® Yepp Maxi, Yepp Nexxt Maxi or Bobike® GO Maxi child seat—no adapters needed (child seats not included)


    Free Adjustment Period:
    New bikes go through a normal break-in period, after which they should be readjusted. All bicycles sold at REI include free adjustments for one year after purchase date—as many times as you need. Included: derailleur and brake adjustments, lateral wheel truing, hub and headset bearing adjustments, tire inflation and chain lubrication. Not included: replacement or installation of new components or accessories, any other services. Call your local REI Co-op Bike Shop for more information.
    View all Tern Electric Folding Bikes
  • Technical Specs

    Best Use

    Urban Cycling

    E-Bike Classification

    Class 1: pedal assist up to 20 mph


    Bosch Performance Line (Gen 3)

    Motor Type


    Motor Torque (Nm)


    Battery Type

    Lithium Ion

    Battery Capacity (Wh)

    500 watt hours

    Battery Removable


    Charge Time (hrs)

    2.5-4.5 hours

    Pedal Assist Range

    32-74 miles

    Bike Frame Material



    6061 aluminum



    Bike Suspension

    Front Suspension


    Suntour custom for Tern

    Fork Travel

    70 millimeters


    Tern HSD custom

    Bottom Bracket

    Motor integrated


    enviolo AUTOMATiQ

    Rear Cogs

    Gates CDX, precision CNC machined cog

    Internally Geared


    Brake Type

    Hydraulic Disc Brake


    Magura MT-4 hydraulic disc

    Brake Levers

    Magura hydraulic


    Tern Atlas H, Cargo

    Front Hub

    Novatec, thru axle, sealed bearings

    Rear Hub

    enviolo Sport 380

    Wheel Size

    20 inches


    Schwalbe Big Ben 20 x 2.2 in. (55-406mm), RaceGuard Puncture Protection

    Tire Width

    2.2 inches

    Handlebar Shape

    Flat Bar


    Tern Sweep, 6061-AL, Tern Andros Adapted


    Tern Physis 3D with Andros Stem

    Seat Post

    Cane Creek Thudbuster ST, Tern Telescope, 34.9/30.9mm


    Tern HSD


    Urban platform with nonslip surface, sealed bearings


    Tern Flux Pro Taper, 1.5 in., angular contact bearings


    Gates Carbon Drive CDX Belt

    Belt Drive



    58 lbs. 11.2 oz.

    Bike Weight

    Bike weight is based on median size, as sold, or the average of two median sizes.



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