When Tern unveiled the original GSD at Eurobike in 2017, they essentially created the compact longtail cargo e-bike category. The pitch was simple: deliver serious hauling capacity (440 lbs) in a package no longer than a standard bike. It worked. The GSD became the benchmark that spawned dozens of competitors.
Fast forward through Gen 2’s refinements in 2020 (beefier frame, Bosch Cargo Line motor, suspension fork) and we arrive at Gen 3 in early 2025. This isn’t a ground-up redesign. Tern took seven years of real-world feedback and focused on three areas: increased capacity (now 463 lbs), Bosch’s Smart System integration, and proper ABS braking borrowed from motorcycles.
The S10 sits in the middle of the four-model Gen 3 lineup. Below it are the P00 and P10 base models without Smart System or ABS. Above it is the R14 with its Rohloff electronic hub and Gates belt drive. The S10 gets you the cutting-edge tech (GPS tracking, electronic lock, app connectivity, ABS) while keeping the Shimano Deore chain drive for easier servicing.
We spent a week with the S10 in southern Utah. Here’s what we found.
My Experience Riding The Tern GSD S10 E-Bike
The riding position is upright and relaxed, exactly what you want on a cargo bike where you need good visibility and comfort for potentially hours of errands. That adjustable two-stage telescoping seatpost I mentioned earlier makes dialing in your fit effortless, and those oversized levers aren’t just for show. Tern redesigned them after feedback revealed the smaller standard ones were painful to use. It’s one of many “little things” that add up to make the GSD feel thoughtfully engineered rather than just assembled.
Speaking of little things, the dual-legged Atlas Lockstand is brilliant in execution, and I’d like to see it applied more often. Most cargo bike kickstands work fine when stationary, but mounting a loaded bike and getting moving from a dead stop can be sketchy. Tern solved this with a remote stand lever on the handlebars. The kickstand stays locked in the down position until you’re ready to go. Hit that lever, shift your weight forward, and the stand releases cleanly as you pedal away. No wobbling, no fighting with the stand while trying to balance kids and cargo.
They also addressed a common kickstand complaint by building a weatherproof container around the hinge mechanism. Previous versions would get gunked up with road grit, gravel, and mud, causing reliability issues. This sealed cover keeps the grime out while maintaining smooth operation. It’s another one of those details that shows Tern actually listens to people who ride these bikes daily.
Out on the road, the GSD S10 just feels dialed in. The hydroformed frame is stiff and handles predictably even when loaded, and those Schwalbe Pickup tires are smooth and quiet. The Bosch system is smooth and quiet, and I found myself gravitating to the Auto mode most often. You’ve got Eco, Tour, Auto, and Cargo modes available, but Auto just reads your effort and delivers the power you need without thinking about it. Flat roads, hills, heavy load, light load, it adapts. I reserved Cargo mode for when I was genuinely maxed out on weight and needed that extra punch.
The power delivery feels confidently capable rather than aggressive. This isn’t a speed demon and there’s no throttle. It’s a true Class 1 bike with a 20 mph assist limit. For some riders that’ll be a dealbreaker, but for most cargo bike users, it’s perfectly adequate and keeps you legal on bike paths where Class 3 bikes are restricted.
One party trick worth mentioning: the GSD can stand vertically on its rear end, letting you park it in a corner of your apartment or office rather than hogging floor space. It’s a simple fold-and-stand maneuver that makes urban storage significantly easier.
The accessory ecosystem is frankly overwhelming in the best way. Tern offers everything from dual kid seats and adult passenger setups to trailer hitches, bike mounts for towing a child’s bike, sun and rain canopies, panniers in multiple sizes, and dozens of other configurations. If you can imagine hauling it, Tern probably has the gear to make it happen. This bike is genuinely designed to replace a car for families, and the accessories back up that claim.
I also never felt anxious parking it outside the grocery store or gas station, which says something about an $8,000 bike. The electronically activated ABUS wheel lock, audible alarm, and flashing lights kick in if someone tries to move it. And if they somehow manage to steal it anyway, the Flow+ app lets you disable the battery remotely, meaning they’re stuck pedaling 80 pounds of dead weight while the alarm blares and lights flash. Good luck making a clean getaway.
From first sit to last pedal stroke, the Tern GSD S10 Gen 3 represents what happens when a brand takes its product seriously, listens to user feedback, and sweats the small stuff. Those “little things” add up to justify the premium price. If you want the best e-cargo bike done right, this is it.
Range
Estimated Range (from Tern): 28-61 miles
Real World Range Test Results:
- Tested Range in Eco: 71 miles
- Tested Range in Cargo mode: 40 miles
Here’s the thing about range estimates on cargo bikes, they’re always a bit of a moving target. With the GSD S10’s ability to haul up to 463 lbs of total weight, your actual mileage will swing wildly depending on whether you’re solo commuting or hauling two kids, a week’s worth of groceries, and someone’s forgotten soccer gear.
The dual battery setup is where the GSD really shines. Out of the box, you get one 545Wh Bosch PowerTube battery, but there’s a second bay ready when you need more juice. Pop in that second battery and you’re rolling with 1,090Wh total, enough for extended adventures without range anxiety. You can charge both simultaneously on the bike or remove them individually to charge wherever’s convenient.
For real-world testing, I set up two runs here in Southern Utah on a local paved recreational path with about 1,000 feet of elevation spread across rolling terrain. At 180 lbs with minimal cargo, these were fairly ideal conditions for range testing.
In our first test, we used the ‘Eco’ mode, the minimum assistance setting 71 miles on a single charge. That’s solidly above Tern’s optimistic 61-mile estimate.
In our Second test, we used ‘Cargo’ mode which is the highest level of assistance on the GSD and in that run we saw 41 miles. Still a very solid number when you’re getting maximum motor support the entire ride.
Look, your range will vary based on terrain, stops and starts, rider weight, cargo load, and weather. But I’ve tested enough e-bikes to know it’s refreshing when real-world results exceed advertised estimates rather than falling short.
With that optional second battery, you’re potentially looking at 140+ miles in Eco or 80+ in Cargo for those marathon errand days.
Power (Motor & Battery)
The power setup on the new Tern GSD S10 is brought to you by Bosch, and it’s important to understand you’re not just getting “a motor”—you’re buying into a complete Bosch ecosystem of premium e-bike tech that all works together.
At the heart of it sits the Bosch Cargo Line mid-drive motor, purpose-built for heavy loads. It peaks at 600 watts, delivers up to 400% pedal assistance, and pushes 85Nm of torque: exactly what you need when hauling kids up hills or starting from a dead stop with a fully loaded rear rack. This isn’t a commuter motor pressed into cargo duty; it’s specifically engineered for bikes that regularly carry serious weight.
But here’s where it gets interesting: that motor is just the starting point. The Bosch ecosystem includes the eBike Flow app for motor tuning (letting you set custom power values at each assist level to match your riding style), the Bosch Anti-Lock Brake system that prevents wheel lockup during emergency stops (which I initially thought was managed by the excellent Magura brakes until I learned it’s actually its own Bosch module), and Flow+ connectivity features for theft protection and GPS tracking. We’ll dive deeper into the app and security stuff in the Display section below, but just know this is a deeply integrated system, not a collection of parts bolted together.
Powering everything is the Bosch PowerTube 545, which as you’d guess from the name, carries 545Wh of capacity and weighs just 6.5 lbs. There’s a handy LED light bar on the exterior displaying charge level, so you can check battery status at a glance without installing it and powering up the whole bike.
The battery mounts cleanly below and behind the seatpost, almost tucked between the post and rear rack, keeping the weight centered and out of sight. And here’s the beauty: if you opt for the dual battery setup, there’s a second dock that lets you effectively double your range. Both batteries mount neatly side-by-side without cluttering up the bike’s clean lines.
Now let’s talk charging, because this matters more than most people realize. The GSD S10 ships with a 4A charger, not the cheaper 2A chargers most brands throw in the box.
Why should you care?
Well, because a 2A charger takes 6 to 8 hours to fully recharge your battery, while this 4A fast charger gets you from 0 to 100% in just 4 hours. But here’s the real win, most of us don’t run batteries down to zero or charge them to 100% if we’re trying to maximize battery longevity. Stay in that sweet spot between 20% and 80%, and you’re looking at a full recharge in about 2 hours. Less time waiting, more time riding and that’s always a good thing in my book.
Components
The Tern GSD S10 runs a Shimano Deore 10-speed drivetrain with an 11 to 51t cassette, giving you a genuinely wide gear range for everything from crawling up steep hills with a loaded bike to maintaining a comfortable cadence on flat ground. It’s a mid-tier mountain bike groupset that’s proven reliable and easy to service at any bike shop, which matters when you’re putting serious miles on a cargo hauler. The chain drive does require regular maintenance (cleaning and lubing), unlike the Gates belt setup on the pricier R14 model, but it’s also significantly cheaper to replace if you trash it.
Stopping power comes from Magura MT5e four-piston hydraulic disc brakes mated to 203mm rotors, and these are not messing around. When you’re hauling 463 lbs down a hill or need to make an emergency stop with two kids on back, you want serious braking force. The quad-piston calipers deliver exactly that, with excellent modulation and power in any weather. And, they work in conjunction with that Bosch ABS system I mentioned earlier. The ABS prevents the front wheel from locking up during hard braking or on slippery surfaces, maintaining traction and control. It’s borrowed straight from motorcycle tech, and it’s a genuine safety game-changer on a cargo bike. Oh, and did I mention the Magura brake levers have tool-less adjustability for finger reach? That means from tiny hands to meat claws, these brakes will fit right in your hands.
Up front, you’ve got an SR Suntour suspension fork that’s been rigorously tested to handle the GSD’s 463lb payload. It smooths out potholes and rough pavement, which is especially appreciated when you’ve got passengers on board who didn’t sign up for a teeth-rattling ride. The fork travel does its job without being overly plush or mushy under power.
Up in the cockpit, Tern’s obsession with adjustability really shines. The Andros adjustable stem is a first for me and frankly, I hope we see it more often in other brands. It offers 110 degrees of rotation, letting you dial in handlebar height and angle without any tools in just seconds. This isn’t a minor tweak, it’s the difference between a comfortable riding position and constantly adjusting your back and shoulders. Combined with the adjustable grips and that wide fit range (4’11” to 6’7″), it means the whole family can genuinely share this bike without compromise.
The handlebars themselves fold and lock into place with a simple mechanism, and there’s a rubber retention strap on the downtube that secures everything when folded for storage or transport. It’s one of those small touches that shows someone actually uses this bike daily.
Integrated into the top tube is a USB Type-C charging port that pulls power straight from the bike’s battery. Charge your phone, your lights, a kid’s tablet, whatever. It’s not revolutionary, but it’s incredibly convenient when you’re out all day running errands or on a long adventure ride.
Lighting is handled front and rear with LED lighting. The 700-lumen Ignis headlight up front is genuinely bright with a wide beam pattern, and it features a one-touch hi/lo beam selector for more visibility or could even be flashed to get someone’s attention. The rear light is always on when the bike is powered, and it automatically brightens when you hit the brakes to alert traffic behind you. At this price point, I’d love to see integrated turn signals, but I’m nitpicking.
The Cane Creek suspension seatpost is another solid addition. It absorbs shocks and vibrations that the front fork misses, making longer rides significantly more comfortable for your lower back.
The seatpost itself is a two-stage telescoping design that’s part of how Tern achieves that massive rider height range. And here’s another ‘little thing’ I loved; the quick-release lever on the seat collar is oversized. Why? Because one of the designer’s wives mentioned the typical smaller levers hurt her hand to operate. It’s a tiny change that makes a real difference, and it’s exactly the kind of thoughtful design that comes from a team that actually rides these bikes with their families.
Contact points are well sorted. The saddle is a ‘Tern x Velo’ collab unit that’s comfortable enough for cargo bike duty (you’re usually sitting more upright anyway), and the grips are by Ergon and have a nice ergonomic shape with good palm support. The pedals are wide platforms that work fine with regular shoes or bike kicks.
Rolling on 20-inch wheels with Schwalbe Pickup tires (2.35 inches wide), the GSD strikes a nice balance between stability, cushioning, and rolling resistance. The smaller wheel size lowers the center of gravity for better handling with heavy loads, while the fat rubber soaks up bumps and provides confident grip in all conditions I tested.
Screen / User Interface / App
The GSD S10 comes equipped with the Bosch Kiox 300 display, a full-color screen mounted on the handlebars showing all the essentials: current speed, battery level, range estimate, assist mode (Eco, Tour, Auto, or Cargo), trip distance, and time. The screen is bright enough to read in direct sunlight and the menus are simple to navigate with buttons on the left grip.
One clever security feature: the Kiox 300 is removable. Pop it off when you park and the motor automatically disables, turning your bike into an 80-pound paperweight that thieves won’t bother with. But, if they do try something, the GSD has a suite of defense tools that make this hauler very tough to steal, but more on that in just a second.
The full connected experience comes from pairing with the Bosch eBike Flow app on your phone. The free features are genuinely useful: ride tracking with detailed maps and elevation profiles, motor tuning to customize power delivery at each assist level, turn-by-turn navigation displayed on the Kiox screen, over-the-air firmware updates, and battery health diagnostics.
Then there’s Flow+, Bosch’s premium subscription at $3.99 monthly or $39.99 annually (with a 12-month free trial included). While I’m generally allergic to monthly subscriptions these days, the security features here are legitimately compelling. You get a digital battery lock that bricks the battery if the bike is stolen, an eBike alarm that triggers lights and sounds when movement is detected, and real-time GPS tracking. The stolen bike report feature generates a complete profile with photos, serial numbers, parts list, and a live tracking link you can instantly share with police and family.
Flow+ also adds parking spot tracking, extended ride analytics, remote battery charge monitoring, and 3D terrain maps. If I lived somewhere with serious bike theft concerns or regularly parked an $8,000 cargo bike outside, the $40 annual fee would be an easy call. The free trial gives you plenty of time to decide if it’s worth keeping.
Tern GSD S10 Model Options
The GSD S10 comes in one frame size that fits riders from 4’11” to 6’7″, which is genuinely impressive when you consider how rare that kind of adjustability is in the bike world. You’ve got three color options to choose from: Beetle Blue (pictured in this review), School Bus Yellow, and Pearl White.
Out of the box, Tern includes some essentials that other brands often charge extra for: front and rear fenders, a 4A fast charger, an integrated ABUS frame lock, and a key set. These aren’t throwaway accessories either. That fast charger alone saves you hours of waiting compared to the cheaper 2A chargers most brands include.
But here’s where the Tern GSD starts to break away from the pack: The optional accessory lineup is, frankly, massive.
We’re talking rain shields and sun shields for passengers, front hauler racks, cargo panniers in multiple sizes, tail hitches for trailers, Sidekick bars for kids (both Joyride and Flat Bar options), the Storm Box for weather protection, Nitelites for side and rear visibility, a Rear Captain’s Chair for adult passengers, a Bike Tow Kit for hauling a kid’s bike behind you, cargo trays, seatbelts, the Clubhouse fort accessory that turns the back into a protected space for kids, Stow Decks for foot support, and on and on. I’m not even listing everything because there are genuinely dozens of configurations.
That’s the real beauty of the GSD lineup. These bikes morph into whatever you need them to be. School run with two kids? Done. Weekly Costco haul? Covered. Date night with your partner on back? Yep. Towing a trailer for a camping trip? No problem. The modularity means one bike can handle multiple use cases rather than being locked into a single purpose.
Is The Tern GSD S10 Worth Buying?
The Tern GSD S10 Gen 3 sits at a crossroads between premium pricing and premium execution. At $7,999, it’s a serious investment that demands a serious question: does it deliver enough to justify replacing your car, or at least your second car?
After spending time with the S10, I can say this: if you’re committed to the cargo bike lifestyle, Tern has built the benchmark. This isn’t a bike that tries to be everything to everyone. It’s laser-focused on being the best compact longtail cargo hauler you can buy, and it succeeds on nearly every front.
The Bosch Smart System integration, ABS braking, 463 lb load capacity, DIN 79010 safety certification, and that absurd accessory ecosystem aren’t just marketing bullet points. They’re the result of nearly a decade of refinement since the original GSD launched in 2017.
Tern has been listening to families who actually use these bikes daily, and it shows in every detail from the oversized seatpost lever to the weatherproof kickstand housing to the remote stand release.The dual battery capability means range anxiety isn’t a factor.
The 10-year warranty and 7-year parts availability pledge mean this isn’t a disposable product. The Flow+ security suite means you can actually park it places without constant worry.
If you’re serious about reducing car dependency or ditching that second vehicle entirely, the GSD S10 Gen 3 isn’t just a premium cargo bike. It’s the cargo bike that actually delivers on the car replacement promise. Tern didn’t just iterate on a good idea. They’ve spent nearly a decade building the benchmark that every competitor is still chasing.
Pros
- The Tern GSD has a Bosch ecosystem of tools and features that really does level up the riding and ownership experience. From OTA firmware updates and motor tuning to theft deterrent, and alarm systems that cause a scene, all with real time gps-live tracking no matter where it ends up.
- Bosch Anti-Lock Brake System (ABS) is a huge win for safer controlled stopping power, especially on a bike made for transporting our kids.
- It’s the ‘little things’ with the Tern GSD S10, things like oversized QR levers that are easier to use to remote kickstand locks so you don’t send off trying to balance with your kids on the back.
- The 600W Bosch Cargo line motor pushes 85Nm of torque and paired with a reserved programming that keeps speeds manageable and power there when you want it.
- Accessories for the GSD S10 are Massive. From kids seats and pannier bags, to sun and rain canopies, cooler bags and lots, lots more, the Tern GSD really can be that family car replacement.
- A 10-Year Warranty by Tern and a 7-Year promise to keep replacement parts on hand in an excellent peace of mind for a premium investment like the GSD offers.
Cons
- The Lack of a throttle and limit of 20 MPH is a good fit for a e-Cargo bike but will still be a turn off for some
- While the GSD is very nicely equipped, no turn signals feels like an easy missed opportunity.
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