Review: Tern GSD S10

Even though it’s my job to think critically about products, there are a few attributes that I don’t think to question. For example, I can't complain that earbuds have to go in my ears. Such is the nature of earbuds. If I have tiny, weird-shaped ears, that’s my own problem.

Likewise, I can't complain that cargo bikes are big and heavy. For a bike frame to have the strength and stability to carry 400 pounds, it has to be correspondingly large. You can't put a 20-pound dog backpack on a Chihuahua, right?

That is common sense, but it makes getting an electric cargo bike less convenient for the people who would most stand to benefit from them. If you live in a crowded urban center, you might seriously consider going carless. But you're SOL with a cargo bike if you don't have enough ground-floor storage.

If you're maneuvering a cargo bike through crowded streets, you'd better practice your one-billion-point turns. And since many e-cargo bikes are too big to transport in many personal vehicles, you better live within a certain distance from a preferred retailer.

These were all things that I considered to be inviolable truths about e-cargo bikes. However, the Tern GSD S10 changed my mind. The entire bike is 180 centimeters long, or about as long as an average road bike. The bike can rest upright on its back end, in case you need to squeeze into an elevator. And the handlebars fold down to slide into the backseat of a car.

In other words: It has all the carrying capacity of a cargo bike, and fewer of the inconveniences. Since they came out in spring of 2018, Tern has been having trouble keeping them in stock. After two weeks of riding the GSD S10, it’s easy for me to see why.

Tern is known for making affordable folding bikes that give you a lot of bang for your buck. So it makes sense that they would include many of the same thoughtful details in the GSD.

Like Tern’s folding bikes, the GSD also has a distinctive geometry. The bike's wheelbase—the distance between the front and rear axles—is the average length for many cargo bikes, or 124 centimeters. But using such small, fat, 20-inch motocross tires makes the bike noticeably shorter.

The rack is also lower than other cargo bikes that I’ve tried, and the Bosch motor and batteries are set under the rack, instead of on the downtube.

All this clever engineering means that overall, the bike's center of gravity is concentrated and much lower, which in turn makes the bike more stable. By now, I've tested a few extended rear-rack bikes. Every time I put my 27-pound toddler into the child seat, we always wobble for a second or two, just long enough for both of us to panic about whether Mommy is going to fall down and bust both of our heads open. But that wasn't the case with the poised GSD S10.

The bike fits a variety of heights. Not only does the seat adjust quickly with a quick-release clamp, the handlebars also rotate to let you sit up or lean forward. The big Ergon handlebar grips provide support for the heel of your hand, and are exceptionally comfortable.

The GSD S10 uses a customizable Bosch Performance motor, which is kept at a max speed of 20 mph to uphold federal guidelines on what constitutes an e-bike. With ten different gears and four different levels of e-assist, I found it pretty easy to get up to 20 mph. And with hydraulic disc brakes, it was easy to stop, too.

You can opt for the cheaper 400-watt-hour single battery system, which will give you a range of anywhere from 31-68 miles. You can also opt to add a 500-Wh battery for a double-battery system that will take your range well into the triple digits. My tester model has the double-battery system. After putting around 30 miles on it, mostly in sport mode, I am less than halfway through one battery.

That's almost all the information I can see at a glance, because the GSD S10 is outfitted with the compact Bosch Purion display. It displays only my current speed, the level of e-assist, and the battery level, although you can scroll downwards to see the odometer and the range. I probably didn’t need to know much more than that anyway.

In a week and a half of testing, I didn’t get anywhere near the 400-pound weight limit. But I did use Tern’s proprietary, reflective and water-resistant panniers to grocery-shop, commute, and haul six months’ worth of hand-me-down baby clothes to a friend’s house (not all at the same time). The bike also has a walk assist mode, for when I inevitably get stuck halfway up a hill and need to push it.

It's also worth noting that the tester was a pre-production model with almost 800 miles on it, and it felt as good as new, which bodes well for the long haul.

Of course, there are only so many hurdles that the GSD can leap. It still weighs sixty pounds with a single battery installed, so you probably won't be throwing it over your shoulder like a Continental soldier.

And you'll still need a place to store it. Just because it’s possible to stand the bike on its end doesn’t mean that you’ll be physically strong enough to do it. I tried several times, and I just can't lift it over my head. I'd feel uneasy leaving it where my toddlers might possibly knock it over, too.

Even though they just came out with the GSD S10, Tern is also currently working on a new GSD S00. It will start out with a bigger 500-Wh battery, and it will have an Enviolo hub with a 380-percent gear range so that you can change gears while at a standstill. So if you can hang on until early 2019, you could purchase the premium version of the GSD for a measly grand more.

But for the moment, if your goal is to reduce the number of trips that you make out of your house by car, the GSD S10 is the best way I've found so far. It handles and feels the most like a commuter bike of any cargo e-bike that I've tried, but with infinitely more storage capacity. And I'm not fooling anyone, anyway: who's still hopping off curbs and darting through traffic on their way to work, anyway? Not me.