Since I brought home my Tern GSD S10 last July I’ve logged over 3500 miles on it as my primary commuter bike. My typical commute is rather different from the average. I have a little over 5 miles on the shoulder of a relatively rural highway that involves very little stopping and either a steep decent (~450 ft downhill over ~0.7 mile, ranging from ~4-18% grade) or a similar ascent (~450 ft uphill over ~1 mile, taken on a slightly different route than ranges from ~6-10% grade) depending on whether I’m headed to work or coming home. Then I board a passenger ferry with relatively restricted bike parking that services downtown Seattle. On the Seattle side, I have a 3.5 mile ride on a mix of fairly crowded city streets, side streets, and a mediocre protected bike lane along an arterial road. This side also includes ~500ft or so of climbing/descent depending what direction I’m going, with the most striking feature being a 4 way stop on a 16% grade (and yes, Seattle really does recommend that as a bike route). Until about a month ago Little T (now 3.5) accompanied me almost every day on this adventure, adding his ~35lbs and daycare necessities to the load.
By pretty much any measure, especially given that I have been doing it in all weather except for snow and ice, this is a challenging commute. The climbs are far from trivial, the descents are steep, I need to transport a solid chunk of both live and inanimate cargo, and the ferry situation means that space is at a premium, so keeping the bike small and relatively easy to maneuver is important. It’s also quite a lot of mileage to be putting on a bike day after day, and the ferry ride means the bike gets a lot of salt exposure just to top things off. When we bought our house and I faced down this commute the GSD was really the only bike I saw as suitable. I’ve never regretted the choice. Other than a run of bad luck with rear flats around 1000 miles in the bike has been basically flawless with only standard maintenance needs. The ability to pop the bike up on its end has made doing most of my own flat repair and maintenance easy. Through 3500 miles that meant several flats being fixed, a chain replacement, and a lot of brake pad replacements, at 3500 I got a full tune with replacement of my brake rotors, rear tire, and cassette/chainring/chain. The front tire still looks good at 3500 miles and I haven’t experienced any issues with the electrical components. The salt water is taking a toll on bolt heads and the brake rotors, hence the rotor replacement at 3500 miles. Given what I put it through on a daily basis I’m solidly impressed at how well it’s held up.
So the GSD is a great, solid, small-form factor electric cargo bike that can definitely take the beating that comes with being a high mileage daily commuter. But can Tern make it better? They think so. New in 2019 is the S00, a new model of the GSD that brings a few changes to the table. The most noticeable are the changes to the assist and drivetrain. The Performance Line motor of the S10 has been replaced by the Performance Line CX. The 10 speed derailleur setup that gives the S10 its name is gone, replaced with an Enviolo (formerly NuVinci) continuously variable hub with a wider gear range. The other changes with the S00 include a 500 WH battery vs the 400 WH that comes with the base S10, a different stock kickstand, and the inclusion of the Tern Cargo Hold Panniers and Abus frame lock on the front wheel as a part of the purchase price. While the S10 is available in 3 colors (Metallic Blue, Beetle Blue, and Mango) the S00 is only available in Mango.
When I first heard about the GSD S10 I was a bit sad it didn’t come with the CX motor because Seattle is very hilly and I like having every bit of power I can get. In practice, I’ve found the standard Performance Line does a solid job on the GSD, so I was interested but not necessarily particularly excited to hear the new model had the CX. The hub vs derailleur issue is more mixed for me. The hub offers benefits of a wider gear range, reduced maintenance, less chain noise, and the ability to shift gears at a stop. On the other hand, it’s heavier than the derailleur setup, costs more, and at least the older versions of the system have a lot of problems with freezing up in cold weather due to water getting into the housing for the shift cables. Also, the full gear range is not available when shifting at a stop, so there are some limitations to the ability to downshift while stopped that can be problematic. Finally, there are fewer shops that are skilled at performing maintenance and repairs on internally geared hubs than derailleur setups, so getting help if something does go wrong can be a bit more challenging. From a personal standpoint I’m just not someone who is in love with the advantages of the hub. I find the lack of specific gears with the continuously variable system frustrating rather than fun or useful, I haven’t found maintenance on my derailleur driven bikes to be onerous, and after a brief adjustment period I automatically downshift when coming to a stop, so it’s extremely rare that I encounter a situation where I wish for the ability to downshift when already stopped. Since I find the hub minimally beneficial to me I’ve never been able to justify the increased cost for my own bikes and they are all derailleur setups. The other aspects of the S00 aren’t particularly useful to me either. I run a dual battery setup, so the improvement in battery life is proportionately small (and since we own multiple Bosch bikes I’ve got access to other 500 WH batteries if I really wanted to put one of them on the GSD for the ~10% boost in battery life). I replaced the stock kickstand with the Rolling Jackass already, and I wanted the Carsick Designs cargo slings over the Tern panniers due to how often I use the bike with a Yepp Maxi on the back.
OK, so for me personally it’s unlikely the S00 would be a worthwhile upgrade. But not everyone shares my neutral feelings on the hub, not everyone wants the Carsick bags, plenty of people are climbing lots of hills and might want the power boost, and a lot of people haven’t already sunk the money in an S10 and are trying to decide which model to go with. While I don’t particularly want an S00 for myself, with >3k miles logged on my S10 I feel like I’m in a pretty good situation to compare the two bikes. And lucky me, I’m friends with the owners of Vashon Adventures, who operate Vashon Ebikes and recently purchased two S00 GSDs after being impressed with my S10 and wanting to add a longtail-style setup to their rental fleet. They wanted some feedback on the new model, especially the kickstand and whether the assist and gear ratios would work well for riding on Vashon, and I was excited for a chance to compare the models and be able to help people figure out which model would be best for them. They graciously agreed to let me try an S00 out for a few days for my commute once they finished assembly and fine tuning.
A few days later, I brought home a beautiful S00 with <1 mile on the odometer and got started setting it up for my commute. I put on the Yepp seat with rain cover that Little T typically rides in, along with a bungie to keep the bags from gaping since I couldn’t use the straps with the Yepp in place, then added my mirror, handlebar bag, cell phone holder, and suspension seat post. The goal was to have the bike set up as similarly as possible to my S10 so that I could focus in on the differences between the models. The only things I left off were the camera mount and turn signal remote for my helmet that my S10 usually sports on the handlebars.
Not surprisingly, since the frame and most of the components are exactly the same, the S00 and S10 feel a LOT alike. If you like the riding position, overall feel, and components of the S10, you’re going to like all those things on the S00. If they don’t work for you, the S00 isn’t going to change that. Accessory compatibility is going to be essentially the same between the two models as well, unless the accessory in question is something that interacts directly with the drive train. I like my S10 a lot so I felt immediately at home on the S00.
Now what about the differences?
The Tern Cargo Hold Panniers are good bags that seem to be built well. Since they don’t come with the S10 they’re essentially a bonus here, which is great if they work for you. I liked them alright, but in comparison to my Carsick slings I found them annoying to use with a Yepp Maxi in place. They’re easier to toss a bunch of small or medium sized items into, but whenever anything is placed in them the full width of the base flares out, which left me kicking them a lot when I walked the bike. They have rain protection if you aren’t using a Yepp, but you lose that feature when you have one in place. And I found I had to use a bungie to keep them from gaping open when I had the Yepp on, which is annoying and not nearly as supportive as the straps on the Carsick slings. Also, if there was anything in them Little T wasn’t able to climb onto the back of the bike without help because they make it much harder to access the lower rails than the Carsick bags do. I think overall the capacity of both setups is similar, but you’ll have to work a bit more to get a full load totally secure on the Carsick bags, while the Carsicks offer a bit more flexibility for weird size/shape loads than the Tern CH bags.
Bottom line: If you’re using the bike without a Yepp, you’d probably want these anyway so it’s great having them included and not spending the $150 as a separate purchase. If you want to use the bike with a Yepp I’d personally recommend the Carsick bags (at least for those in the US), but you could always sell off the Tern bags to help fund that purchase.
The Abus Frame Lock on the front wheel is a favorite accessory of mine and I was so desperate to have one as quickly as possible on my S10 that I stole the one off my Packster until G&O was able to get them in stock for the GSD. It makes dropping my son at daycare so much faster and easier than fumbling with my big chain lock, and it adds an element of extra security for longer stops. At $40 for the aftermarket option this isn’t a particularly pricy add-on, but it’s nice having it there. Perhaps more importantly, if you get the S00 you get batteries that are keyed the same (both as each other and as the frame lock). Adding that option with an add-on frame lock adds ~$40 extra on top of the price of the lock. My only gripe here is that Tern opted to go with the version of the lock that retains the key. This means that if you have the lock unlocked, the key cannot be removed from the lock. This prevents you putting any sort of keychain on the lock, and means that someone can lock your bike and steal your batteries if you forget to lock the frame lock and walk away. I’m told that a lot of people really love this system and I know it’s fairly popular to have the key retaining version of these locks in Europe. Personally, I hate it. It doesn’t work with my key management system and I’m paranoid I’m going to snap the key off in the lock while pushing the bike up to a rack (I’ve done something similar with the rain canopy attachment on the Packster), lose the keychainless key when I’ve got the bike locked somewhere, or leave the key in the lock while I’m away from the bike (and have used my big chain as the primary lock) and come back to missing batteries.
Bottom line: If you don’t mind the retained key, having the lock included is a plus and having the batteries keyed alike with the lock is awesome.
The larger battery is great and not easily available for the S10, but it’s a marginal boost and a lot of people are never really going to notice it.
Bottom line: Alright I guess.
Now we get to the more interesting bits.
The kickstand is a different model than the almost universally panned Hebie dual kickstand that came (and currently still comes) stock on the S10. On paper, this new Ergotec kickstand has a lower weight rating than the Hebie (60kg vs 80kg) but Tern contends, and I agree, that in real life use the Ergotec is both more robust and more stable. In use on flat, smooth ground I found the Ergotec stand was adequate for supporting the GSD with Little T in the Yepp seat without me feeling like I had to be actually holding the bike at all times (just standing immediately next to it was enough). The Hebie did not pass this test. However, when the ground becomes at all uneven, or there’s any more force on the back of the bike, things still break down. I would not consider the Ergotec stand adequate for a child to climb on the back of the bike themselves without an adult prepared to fully support the bike. When I tried to do basic things like push something into the bags with Little T already in his seat I found the bike was prone to tipping off the stand. And when I used the stand on any uneven or rough ground I needed to be holding the bike with both hands or straddling it to keep it stable. None of this is up to the standards I want to see in a kickstand intended for use with multiple children on a cargo bike. I don’t think the Ergotec will fall apart as quickly as the Hebie, and I do think it’s a stability upgrade, but it’s still not there yet.
The other way in which the Ergotec fails is in the ease of setting and unsetting the stand. With my Rolling Jackass on my S10, or with the double stands on our box bikes, setting the stand means placing your foot so you push the stand down until it touches the ground, and then pulling the bike backward so the stand sets against the ground. There is no lifting of the bike involved. It can also be done from either side of the bike. Removing the bike from being set on the stand only requires pushing the whole thing forward at the handlebars. No part of the bike needs to be lifted by the rider. This is not the case with the Ergotec. In order to set or unset the Ergotec stand, the rider needs to lift the front end of the GSD several inches off the ground. Doing this substantially changes the balance of the bike and makes it very prone to tipping if you move the wrong way. At the same time you must place your foot properly on the stand to push it in or out so that it moves to the desired location. The placement of the Ergotec meant that I was often getting stuck on the pedals while trying to do this. And the stand can only be set from the left side of the bike due to the way the legs of the stand interact. Even after 3 days I dreaded having to take the bike on and off the kickstand and it made me long for my S10. Heavier and taller riders (mostly men) are going to struggle less with this aspect of the kickstand, because they have a better physical position and more mass to counteract any problematic movement of the bike when its lifted and usually more muscle mass to make the actual lift easier. Shorter and lighter riders (mostly women, a group that is a large portion of the cargo bike buying market, especially for smaller form factor bikes like the GSD) are going to find it more problematic.
Tern reports that the Ergotec kickstand is compatible with the S10 and is filtering into the warranty replacement queue. They cannot say how long that will take though, so if you get an S10 new it will likely come with the Hebie kickstand, at least for the time being, and if your Hebie stand breaks you may end up with either the Hebie or the Ergotec as a replacement with no clear way to know yet which it will end up being. I have relayed my thoughts on the kickstand, and the things I would prefer to see, to Tern and have been told that they do consider this an important issue and are working on a new strategy, though they cannot say what that is as of yet. I hope they decide to stun me with an awesome kickstand soon.
- As I predicted, there have been numerous reports of children pulling GSDs over from barely touching them before their parents could get there to stabilize the bike and GSDs just falling over due to totally normal loads with the current kickstands, especially the Hebie. Also, some people are reporting issues like tendonitis being caused by using these stands, with substantial pain that interferes with daily activities being a result. These are NOT small issues and I really hope manufacturers of midtail and longtail bikes start taking the health and well-being of those buying their bikes into account, since they seem intent on ignoring ease-of-use concerns.
- Tern DOES seem to be taking this seriously and has decided to wow me with an awesome kickstand. At least I hope so. At Eurobike this year they announced the Atlas kickstand, which appears to be a solution to all the issues with the Hebie and Ergotec stands. At this time it is not yet available, but they have promised it will be coming out soon and that there will be a discount for those who already own the GSD and are having issues with their current stands. I’m not expecting this to be an included feature of the GSD moving forward (at least not the base model) but even having it as a manufacturer accessory, like the Clubhouse or Sidekick bars, will make it available to everyone in a way the Rolling Jackass isn’t, and that is a huge improvement. I’m looking forward to getting to actually see the Atlas stand in action soon, but I’m very hopeful that it is going to be the kickstand the GSD deserves.***
Bottom line: Better than the Hebie, still not up to my standards for a stand on a kid carrying cargo bike. If you won’t be carrying kids you might be fine. If you are carrying kids I still strongly recommend you budget for a Rolling Jackass until Tern comes up with a better solution.
Moving on to the drive train components we come to the internally geared hub that the S00 uses. Enviolo is a rebranding/update of the NuVinci hubs many will be familiar with from other bikes. These hubs are basically the equivalent of a continuously variable transmission for a bike and have become popular in e-cargo bikes in the last few years. However, in many of those contexts the hubs were being used outside of or on the border of the manufacturer ratings for the hub. With the rebranding, the Enviolo hubs now come in a few different versions – with either 310% or 380% gear ranges – that are intended for a variety of uses. The GSD uses the cargo version of the Enviolo hub, which has a 380% gear range and specs that mean the hub is no longer being used outside of the manufacturers recommendations in e-cargo applications. Although used with a belt drive on some bikes, the hub is paired with a chain on the GSD, which as I understand it is due to limitations of the frame. Those hoping to get away from having a low hanging derailleur should note that there is a chain tensioner on the S00, so you will still have something hanging down, though it should be less sensitive than a derailleur. While older versions of the hub used a grip shifter with a little bike rider on a hill of varying height (depending where you had it set), the GSD has a newer version of the shifter that looks more like typical grip shifters and has fairly subtle +/- markings. Tern lists the gear range for the S10 as 29-92 gear inches and the range for the S00 as 26-99″. So the gear range of the S00 is wider than what is offered by the 10 speed setup.
The assist system is also different, as previously mentioned, and the S00 comes with the Performance CX motor from Bosch. Originally designed as a mountain bike motor, this is a higher torque (and heavier) motor than the standard Performance Line found on the S10. It’s become fairly popular in the cargo biking world (it’s the motor we have on both the Packster and Load) and is capable of delivering up to 75 nm of torque vs 63 nm for the standard Performance Line motor. It also offers the option of eMTB mode, which should adjust the assist automatically while you pedal, allowing use of the full range of power available from the motor without being as “jumpy” as if you just leave the bike set to Turbo.
The combination of these two factors is intended to make the S00 a better climber than the S10, and they also account for most of the added cost of the S00 over the S10. Honestly, I was underwhelmed in this regard. Don’t get me wrong, the S00 is a good climber. But so is the S10. In fact, when I first rode the S10 before deciding to purchase one I was expecting to be a little unimpressed with the climbing ability but found it was totally adequate for what I needed (which, again, is a fairly grueling commute). So perhaps there just wasn’t much room for the S00 to wow me in this regard since the S10 is already fairly solid. At the low end of the range I found that the on-paper lower gear range of the S00 didn’t translate for real world performance. I have a few “stress tests” for this. First, stopping and attempting to restart at the 16% grade 4-way stop on Yesler. In this test the S00 actually fared a bit worse than the S10. Neither bike was particularly easy to get going, but with the S00 the bike finally got going so late in my second attempt to start off that I thought I was going to have to walk the bike over to the sidewalk and push it up the hill. I just couldn’t get the pedal moving quickly enough to get the assist to kick on, even though the bike was at the lowest gear setting and the assist was set to turbo. With the S10 I can usually accomplish this on the first try, and when I do occasionally need a second attempt I always get the assist to kick on pretty quickly. I’ve never felt like I might need to walk the bike. That said, this is something that’s fairly weight sensitive and I think this is a place where the added weight of the hub and CX motor (which totals ~6 lbs) may be offsetting any gains from the lower gear range. The second test is the ride up Yesler itself. On this I noticed very little difference between the two bikes. I was still most comfortable doing most of the steepest section at the lowest end of the gear ratio and I wasn’t any faster and didn’t feel like I was working any less with the S00 than the S10. The final test is the ferry hill I climb on Vashon. This is a more moderate grade than Yesler and here the CX motor was able to show off a little bit. I could get up the hill ~2 mph faster than usual and it felt a little easier. Nothing dramatic, but noticeable.
So I found modest gains compared to my S10 on moderate hills but not much change on the steepest sections of my ride. At the higher end of the gear range I did notice a pretty big difference between the two bikes. On the S10 I find that I spin out in the highest gear right around 21-22 mph. This is typically fine since the assist cuts off just before 20 mph but once in a while I wish for just a bit more at the high end of the range. With the S00 I didn’t spin out until >25 mph. In fact, I had to test it out on downhill to the ferry because that was the only place I could safety and easily go fast enough. While this won’t be useful very often on a 20 mph capped ebike, riders in hilly areas may appreciate it at times. In terms of noise, since the S00 has a chain drive rather than a belt I didn’t find a dramatic difference, and the lack of a full chain case is going to limit the maintenance gains you get from having the hub over a derailleur. It will still be a bit less noisy and require less maintenance than the S10 though.
Bottom line: There are some gains here, especially in terms of maintenance potential, but they are not huge. If you like internally geared hubs, this model is likely the right choice for you. If you’re happy with a derailleur, I don’t think you are going to find anything here to justify the added cost over the S10. If you’re looking to put the GSD on a bus bike rack or otherwise planning to be lifting it a lot, it’s worth thinking about whether the extra weight of the hub + CX motor will be a problem for you. I didn’t expect it to matter but found myself surprised at how noticeable the difference was when I lifted the bike (but the S10 is near the limit of how much bike I can comfortably lift, so it may be different for you).
On the whole the S00 model of the GSD takes everything that made the S10 awesome and adds a few tweaks that some will find useful and some won’t. Tern did a great job of adding those things without introducing any downsides other than cost (and I guess a lack of color selection). Both are really amazing bikes that rival the carrying capacity of a full longtail in a footprint that is dramatically smaller. Both will be reliable transport for your cargo or family for thousands of miles. While there are still some changes to be made to perfect the bike, Tern has proven themselves to be responsive to feedback about the bike and what accessories are needed for it, which gives me a lot of hope that things will continue to get even better. Either model is a solid purchase and almost certain to make you happy.