Tern HSD S+ electric bike review

The Tern HSD S+ is a compact cargo bike with big carrying capacity. And more importantly, it can fit into your life and space even if you don't think you have room for a cargo bike. While it isn't a folder, it has a collapsible, space-saving design, and along with the impressive — seriously impressive — component package, which includes a high-end Bosch mid-drive motor along with an automatic transmission, there really isn't anything else quite like it on the market.

The Tern HSD S+ is a step above (really a few steps above) superficially similar utility bikes we really like, such as the Rad Power RadRunner 2, but for the money, you get incredibly solid performance and features from a bike you won't have to put much effort into maintaining. Despite its steep price tag, it's worth serious consideration if you’re looking for a capable hauler that can really do it all.

A top-of-the-line electric cargo bike with high-end parts, a compact design and fantastic performance, the HSD S+ is one of the most impressive cargo bikes we've tested.

The HSD S+ may be too expensive for many potential buyers, but the same frame is available with a conventional derailleur transmission for a lot less in the HSD P9.

The Tern HSD S+ is the top model in Tern's HSD electric midtail cargo bike lineup, with every modern cycling convenience: Enviolo's CVT hub, coupled with the company's new AutomatiQ automatic transmission, means all you need to do is set your preferred pedaling cadence and the bike automatically changes gearing to match any terrain. A rack system is capable of hauling large items (and has rubberized feet on the rear that let you stand the bike upright for easy storage), a smooth-running Bosch mid-drive motor, Magura's excellent hydraulic disc brakes and a well-spec’d front and rear lighting system. It’d be hard to find anything better-equipped than the HSD S+. An adjustable stem makes it easy to get the right handlebar position, and a Thudbuster-equipped seatpost and suspension fork soak up road noise — you don't really notice that you’re on 20-inch wheels.

The overall impact of the high-end parts is that the bike feels incredibly solid and functions very smoothly from the first ride. More importantly, the belt drive and internally geared hub mean that the bike will require very little maintenance over time. We imagine that most riders won't be servicing the hydraulic brakes themselves, so aside from keeping air in the tires, there's little to do on a week-by-week basis to keep the HSD S+ running like new. Periodic visits (Tern recommends every six months) to the bike shop should do it.

The HSD, like the rest of the models in Tern's utility bike lineup, gives you a huge amount of hauling ability in about as small a footprint as possible. It's a small vehicle that's easy to handle for almost any adult. It can get you almost anywhere reasonable from commuting and shopping and kid-hauling to touring and bike camping, and can be adjusted to fit anyone in the family. It's a compelling package for something this expensive.

The HSD is what's known as a midtail utility bike (its rack is an extended version of a traditional pannier rack). It's not as long as a "longtail" like the Tern GSD or the many full-sized cargo bikes that have followed the rough design of the original Xtracycle, but it supports large panniers like those designed for longtail bikes and can carry almost as much cargo. In the HSD's case, it is rated to carry up to 374 pounds, passengers included; the rack itself is rated to carry 132 pounds of cargo (or a mix of cargo and child seating).

In testing, we used a couple of sets of standard panniers and a set of cargo-bike specific double-length panniers from Rad (meant for that company's longtail bikes). You can also mount a single child seat on the rack (the slightly larger Tern GSD can support a pair of child seats).

We put the HSD into service as part of our daily errand-running, appointment-going and general around-town tasks over the course of several months, during which time we hauled groceries, multiple 40-pound sacks of cat litter and chicken feed, dry cleaning and more (getting right up to the rack's 132-pound limit) around our test course. We found the Bosch mid-drive unit up to the challenge of our hilly neighborhood, making it up the 10% and 12% grades without a hitch.

There's plenty of power on tap, and the Bosch drive is quick to respond to your pedaling input via torque sensors. That means the bike is quick off the mark from stop signs and maintains speed effortlessly as well, and it's a confident handler that we felt completely confident on negotiating traffic throughout the day. (Small-wheeled cargo bikes are a great idea, and one that's very well-implemented here.) Even putting the electric drive aside, it rides like a real bike, not a cargo bike.

The AutomatiQ system is clearly aimed at those who are looking for a cargo bike as a car replacement, and we think most casual riders will really appreciate it. We’re longtime fans of Enviolo's continuously variable transmission, which dispenses with discrete gears and lets you shift in a smooth curve to deal with everything from flat terrain to steep hills. That system here is managed by a computer that adjusts the hub to match your pedaling cadence; you enter your target cadence manually, and the system then handles shifting from then on. It's a pleasure to use as intended, removing the distraction of having to shift to handle varying terrain and letting you concentrate on getting from A to B.

In our testing we found (as Tern advised) that the system works best at a moderate cadence of around 60-70 pedal revolutions per minute. If you like to maintain a higher cadence (riders coming from road cycling may be more used to cadences of 100 rpm or more) you may find that the automatic shifting seems slow, or leaves you in too high a gear when you’re looking to maintain speed on the flats. That said, this was a pretty minor annoyance and one that only enthusiasts are likely to notice (we felt it most when trying to keep up with car traffic).

Loaded descents were easily managed with the Magura hydraulic disc brakes, which feel great — very positive engagement, and they make it easy to modulate speed. We never felt that we were pushing the bike beyond what it was designed to do or capable of doing. The 20-inch wheels give the HSD a low center of gravity so it feels very stable even loaded; we had no problem digging into turns at speed on winding country roads.

The rear rack is designed to let you stand the bike on its end so you can store it vertically or take it into an elevator. Even though by any measurement the HSD is relatively compact for a "cargo" bike, this saves a significant amount of space over anything remotely similar and just makes it a lot easier to get into tight spaces securely than any other cargo bike we’ve run into.

The HSD S+ we tested is quite pricey, expensive enough that it seems like a lot even if you consider that it can really replace a car for a lot of local errands. That said, it's something that can be addressed — as you might with a car purchase — by stepping down a couple of trim levels.

Tern offers the bike (and the rest of their utility lineup) in a range of component options — you can give up the automatic transmission and internal hub and get the conventionally outfitted (9-speed derailleur transmission) Tern HSD P9 for $2,000 less. That's still pricey, but not out of line for what's included.

For most people, stepping down to the P9 won't be a lot to give up. While we really like the Enviolo system, and think many riders would appreciate the AutomatiQ automatic transmission, experienced cyclists accustomed to maintaining high cadences may find it a little frustrating. You can drop into manual mode, but then the HSD's transmission works as nine-speed rather than maintaining the infinitely variable gearing the Enviolo hub is capable of, which is a bit of a letdown.

The Tern HSD S+ has incredibly impressive build quality — it's just head and shoulders above the cargo bike competition, and it's lighter, smaller, nimbler and easier to store than anything else we’ve found that can carry a comparable amount of cargo.. If you want the best possible combination of features in a small utility bike, it's fantastic.

But for most people, it's probably overkill. We imagine most riders would be perfectly well served by one of Tern's cheaper configurations (such as the HSD P9), which offer most of the performance for thousands of dollars less