Tern GSD S10 Electric Bike

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A city-ready utility e-bike made with families in mind, the Tern GSD S10 electric bike can carry 2 kids or up to 400 lbs. of cargo, despite being the same length as a standard e-bike.


  • Folding technology compacts to a third of its full size in only 10 seconds so you can store it in your apartment, fit it in the elevator or stash it on a train
  • Carries 2 kids (Thule Yepp Maxi child seats sold separately) and a week's worth of groceries—up to 400 lbs. of cargo, including rider
  • Low step-through frame makes getting on and off easy
  • When you're riding uphill with the kids on the back, rely on the Bosch motor and battery to deliver outstanding performance and power
  • Adjusts to fit riders from 4 ft. 8 in. to 6 ft. 4 in., so the whole family can ride
  • Specs and images are subject to change


This e-bike comes with Coast to Coast Support, which includes:
  • 1 year of free adjustments (see more below)
  • In-store bike assembly
  • Pickup in store or curbside
  • Bike experts available at 170+ bike shops
REI Co-op Members get more:
  • An additional year of free adjustments (2 total years; see below)
  • Free flat tire repairs (labor only; parts not included)
  • 20% off shop services
More about our free adjustments:
New bikes go through a normal break-in period, after which they should be readjusted. All electric bicycles sold at REI include free adjustments for the defined period (one year after purchase date for non-members, or two years for REI Co-op Members)—as many times as you need. Included: derailleur and brake adjustments, lateral wheel truing, hub and headset bearing adjustments, tire inflation, chain lubrication and e-bike firmware updates. Not included: replacement or installation of new components or accessories, any other services. Call your local REI Co-op Bike Shop for more information.

UL2849 certified
View the Tern GSD Product LineView all Tern

Technical Specs

Best Use

Urban Cycling

E-Bike Classification

Class 1: pedal assist up to 20 mph


Bosch Performance Line, 250W

Motor Type


Motor Torque (Nm)

63 Newton meters

Battery Type

Lithium Ion

Battery Capacity (Wh)

400 watt hours

Pedal Assist Range

31 - 68 miles


7005 aluminum



Bike Suspension

No Suspension


6061 aluminum


Tern GSD Custom with forged 6061 aluminum DH crank arm

Bottom Bracket

Motor integrated


Shimano Deore 1 x 10-speed

Rear Derailleur

Shimano Deore Shadow+

Rear Cogs

Shimano 11-36T, 10-speed

Number of Gears


Brake Type

Hydraulic Disc Brake


Magura MT-4, 4 piston hydraulic, 180mm rotor

Brake Levers

Magura, hydraulic


Tern Atlas, ultra wide 36mm, dual reinforced joint

Front Hub

Tern Atlas, Boost thru-axle

Rear Hub

Tern Atlas, Boost thru-axle, e-bike reinforced design

Wheel Size

20 inches


Schwalbe Super Moto-X, 62-406, Green Guard puncture protection, Reflex

Tire Width


Handlebar Shape

Moustache Bar


Tern Sweep, 27°, 6061 aluminum, Tern Andros adapted


Tern Andros (G2), adjustable, forged construction, patented technology

Seat Post

Tern Telescope, 34.9mm, 2014 aluminum


Tern GSD, with rear handle


Urban with nonslip surface, sealed bearings


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


10-speed, DHT for e-bike, GST corrosion-resistant coating


(With 1 battery): 59 lbs. 10.5 oz.

Bike Weight

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



Size Chart

One Size
Height Range4'11"-6'5"

How we measure bikes

  1. Standover Height Standover Height is a measurement from the ground to the top of the top tube, measured at the midpoint of the top tube.
  2. Reach Reach is the horizontal distance from the center of the cranks to the center of the head tube, measured at head tube level.
  3. Stack Stack is the vertical distance from the center of the cranks to the center of the head tube, measured to the top of the head tube.
  4. Effective Top Tube Effective top tube is the distance from the center of the head tube to the center of the seat tube/seat post, measured parallel to the ground.
  5. Seat Tube Center to Top Seat Tube length is the measurement of the seat tube, from the center of the cranks to the top of the seat tube.
  6. Head Tube Length Head Tube Length is measured from the bottom to the top of the head tube.
  7. Head Tube Angle Head Tube Angle is the acute angle between the head tube and the ground (measured towards the rear of the bike)
  8. Seat Tube Angle Seat Tube Angle is the acute angle between the seat tube and the ground (measured towards the rear of the bike).
  9. Bottom Bracket Height Bottom Bracket Height is a measurement taken vertically from the ground up to the center of the cranks.
  10. Wheelbase Wheelbase is the measurement from the center of the front axle to the center of the rear axle.
  11. Chainstay Length Chainstay Length is the measurement from the center of the cranks to the center of the rear axle.
  12. Fork Offset Fork Offset, or rake, is the distance from the front axle to a line drawn parallel to the center of the head tube or steering axis.

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