Tern GSD S10 Folding Electric Bike
Built to carry 2 kids plus groceries—or a whole lot of cargo—and featuring dual-battery technology that's ready to ride all day, the Tern GSD S10 electric bike just might be able to replace your car.
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- The same length as a regular bike, the GSD S10 is incredibly easy to own and use, thanks to space-saving features like FlatFold and Vertical Parking
- With FlatFold, the handlebar and stem fold down next to the frame, and the seat post telescopes all the way down, enabling the bike to fit in larger vehicles and tight spaces
- Regular bikes take up a lot of floor space, but the GSD S10 parks vertically, so it takes up about as much space as a potted plant—perfect for city apartments and elevators
- Bosch® Cargo Line Motor provides up to 85 Nm of torque and 400% support, making it easier to tackle big hills and ride with heavy loads
- Shimano Deore shifting with Deore Shadow+ rear derailleur offers crisp, reliable changes across the wide-range 10-speed cassette
- Adjustable cockpit comfortably fits riders 4'11" to 6'5" (150 to 195 cm)
- Super tough Atlas Lockstand™ automatically locks when engaged—just press a button on the handlebar to unlock
- Heavy-duty frame-integrated rear rack and integrated lower decks offer plenty of kid and cargo capacity—this bike handles up to a 440 lb. (200 kg) Maximum Gross Vehicle Weight
- Magura® MT5 eSTOP 4-piston hydraulic disc brakes deliver powerful and responsive braking in all conditions
- Always-on RearStop™ brake light helps you signal stops
- Integrated Abus® wheel lock is keyed-alike with the battery
- Upgraded Atlas wheels feature custom CNC-machined hubs for extra strength and durability
- Integrated Tern Valo direct head light provides 150 lumens (41 lux) to help you see and be seen
- Compatible with a wide range of cargo- and passenger-carrying accessories (not included)
- Fits up to 2 Thule® Yepp Maxi seats (not included) with no adapters needed
- NOTE: Specs and images are subject to change based on component availability
Imported.
- 1 year of free adjustments (see more below)
- In-store bike assembly
- Pickup in store or curbside
- Bike experts available at 170+ bike shops
- An additional year of free adjustments on e-bikes
- 20% off shop services
- Free tubes with purchase of flat tire repair (Co-op Cycles brand tubes only; tube must be installed at time of purchase)
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
| Best Use | Urban Cycling |
|---|---|
| E-Bike Classification | Class 1: pedal assist up to 20 mph |
| Motor | Bosch Cargo Line Motor |
| Motor Type | Mid-Drive |
| Motor Torque (Nm) | 85 Newton meters |
| Battery Type | Lithium Ion |
| Battery Capacity (Wh) | 400 watt hours |
| Battery Removable | Yes |
| Charge Time (hrs) | 2.5-4 hours |
| Pedal Assist Range | 26-53 miles |
| Frame | 6061 aluminum |
| Foldable | Yes |
| Step-Through | Yes |
| Bike Suspension | Front Suspension |
| Fork | Chromoly steerer; 32 mm stanchions |
| Fork Travel | 70 millimeters |
| Crankset | 6061 aluminum DH crankarm |
| Bottom Bracket | Motor Integrated |
| Shifters | Shimano Deore |
| Rear Derailleur | Shimano Deore Shadow+ |
| Rear Cogs | 10-speed 11-36T |
| Number of Gears | 10 gear(s) |
| Brake Type | Hydraulic Disc Brake |
| Brakes | Magura MT5 |
| Brake Levers | MT5 E-Stop, hydraulic, with brake sensor |
| Rims | Tern Atlas, ultrawide 36 mm, dual reinforced joint |
| Front Hub | Tern Atlas, Boost thru axle, cargo-optimized design, sealed cartridge bearing |
| Rear Hub | Tern Atlas, Boost thru axle, Syntace X-12 standard, cargo-optimized design |
| Wheel Size | 20 inches |
| Tires | Front: Schwalbe Big Ben Plus 20 x 2.15 in. (55-406); rear: Schwalbe Super Moto-X 20 x 2.4 in. (62-406); both with Green Guard puncture protection and Reflex |
| Tire Width | 2.4 inches 2.15 inches |
| Handlebar Shape | Moustache Bar |
| Handlebar | 6061 aluminum |
| Stem | Tern Andros, adjustable, forged construction, patented technology |
| Seat Post | Tern Telescope, 34.9/30.9 mm, 2014 aluminum, telescopic |
| Saddle | Tern GSD by Velo with rear handle |
| Pedals | Urban with nonslip surface, sealed bearings |
| Headset | Tern Flux Pro Taper, 1.5 in., angular contact bearings, Physis integrated |
| Chain | 10 speed, DHT for eBike, GST corrosion-resistant coating |
| Weight | 74 lbs. 0.5 oz. |
| Bike Weight | Bike weight is based on median size, as sold, or the average of two median sizes. |
| Gender | Unisex |
| Sustainability | Contains recycled materials |
| One Size | |
|---|---|
| Height Range | 4'11''-6'5'' |
How we measure bikes
- 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.
- Reach Reach is the horizontal distance from the center of the cranks to the center of the head tube, measured at head tube level.
- 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.
- 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.
- 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.
- Head Tube Length Head Tube Length is measured from the bottom to the top of the head tube.
- Head Tube Angle Head Tube Angle is the acute angle between the head tube and the ground (measured towards the rear of the bike)
- Seat Tube Angle Seat Tube Angle is the acute angle between the seat tube and the ground (measured towards the rear of the bike).
- Bottom Bracket Height Bottom Bracket Height is a measurement taken vertically from the ground up to the center of the cranks.
- Wheelbase Wheelbase is the measurement from the center of the front axle to the center of the rear axle.
- Chainstay Length Chainstay Length is the measurement from the center of the cranks to the center of the rear axle.
- 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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Great bike for hauling loads and errands
I have my GSD set up for shopping and other errands. It can carry up to 440 pounds (including the operator). The Bosch motor is powerful and can assist you up steep hills. The quality of the bike is excellent, although the seat broke with less than 50 miles, and I replaced it with a Brooks B-17 I had in the basement. The Tern GSD is for easy-going trips, and you will not be a speed demon on this bike. I bought an extra battery for this bike, but I have not needed it, to be truthful. When I purchased the e-bike REI did not sell the extra battery; now they do. You may need to source other accessories from bike shops like Propel. There are a lot of accessories for this bike. The GSD is the second E-bike I have had delivered by REI. They are easy to assemble and get on the road. Both bikes had minor damage from shipping, so beware. I highly recommend this bike for those who want to run errands, haul kids or replace their car.
Great handling cargo bike.
I put a Thule Yepp child seat on the back and the transporteur rack on the front. The center of gravity remains low and the bike does not feel tippy. I can put my grandson in the back and ice chest of refreshments upfront and the bike still feels balanced. Kickstand is heavy duty (I have a 2020 model) and holds a fully loaded bike securely. I am 5'7" and the bike allows me to ride fairly upright. Electric assist eliminates need for a more haunched over aerodynamic position. I hit a log at night which damaged the light but no discernible damage anywhere else which attests to the solid build. I have only done 5 - 10 mile rides running errands and I recharge about every 30 miles. Consider this bike if you like minivans and want to throw two kids on the back and go shopping at the farmer's market. Get a Specialized Turbo Vado SL if you want a light, fast commute bike.
Great example of a smaller eCargo bike
Everything is really awesome, save for two things. The large cable harness that comes from under the down tube and heads up toward the handlebars isn't managed very well and the suspension fork crown can collide/scrape against it when flipped the wheel around to fold the handlebars down. This can be somewhat addressed with a strap or zip tie to keep it out of the way. The other issue is the vertical standing feature. It's great in concept but the bike is SO heavy that it's really difficult to do, and it's not that stable when vertical because the footprint is quite small. So, we honestly just park it like a regular bike in our hallway and don't bother to fold it anymore unless we're loading it into our Honda Fit. Beyond that, super great! Just make sure that REI gives it a thorough exam because ours had a malfunctioning rear brake light that they had to fix and it took about a week.
Feels like a much smaller bike
I've wanted a GSD since they were originally announced, but I really couldn't justify a cargo bike. I can carry all the cargo I need on my Brompton. I have one grown child. My dogs hate bike rides. But now it's 2021 and we are in our second year of COVID. We don't own or want cars and we would prefer to stay off the bus for the time being. I joined a new gym that isn't far away, but is up some of Seattle's famous hills. I found myself able to justify a GSD and and HSD. About walking the bike upright/walking it upright into elevators/parking upright: as another reviewer said you *can*. But it's a very heavy bike and it is unwieldy. I don't think I'll try it in my elevator again. I had serious trouble getting it back out and our elevator is big enough to not need to upend the bike. Likewise trying to "walk" it vertically through the house. I got better at it, but I need to lean it on my hip. I did master standing it up to store it. You don't need to try to lift it, you just walk backward with the rear brake on. But if you are a small/weak person, you will need to lean back. The fact that storing/walking vertically was much more challenging than Tern would have you believe almost led me to immediately return it for another HSD. So which do I like more? I really can't answer. If I could really only keep one, it would be the HSD because I really don't *need* the cargo capacity of the GSD. But I honestly reached for the GSD more often, despite it being more difficult to get in and out of the apartment. I *did* return this bike, though. I decided that the S00 was worth the extra money. The Gates drive and Enviolo hub mean next to no maintenance. But there is nothing wrong with this bicycle. If you buy it, you will probably love it. I do.
A new commuter for the kids
This is my first ebike and cargo bike, replacing a pull behind trailer. It's a joy to ride. The bike is more red in the photos and more orange in person.