Today Zwift starts selling their first smart trainer, the Zwift Hub. Announced about a month ago, this ‘new’ smart trainer is essentially a repackaged JetBlack VOLT V2 trainer, but at a substantially lower price point than virtually every other direct drive trainer: $499. Most trainers with these specs tend to float in the $799-$999 price ballpark, thus making this potentially one of the best deals in the smart trainer world. However, Zwift has doubled down on this with a revamped setup ‘experience’ that aims to make it easy to get up and running, even if you know almost nothing about bike parts.
While we’ll get to all the nitty-gritty details in this review, it’s notable that this trainer isn’t limited to Zwift. It follows all of the ANT+ & Bluetooth Smart trainer/power standards, and works with any platform out there (for example, I’ve used it with TrainerRoad just fine). Further, while Zwift’s goal with this trainer is heavily focused on attracting new subscribers and recurring revenue to the platform, the company says it’s not selling this trainer for a loss – but is in fact making a small profit. I don’t doubt that, looking at OEM costs elsewhere, the pricing lines up. Keep in mind, Zwift isn’t selling this through retail channels, so they don’t have to account for a retail markup.
With that out of the way, I’ve been testing two different Zwift Hub media loaner units. The first back in August/Early September, which I wrote my initial hands-on piece about. That was then replaced with a different unit in mid-September, which I’ve used since. That new unit also includes the final firmware implemented to address some earlier accuracy issues I had (and it includes a different factory calibration process, which is why they sent new hardware just to be sure).
Both of these will go back to them once I’ve finished up here, as usual. If you found this review useful, consider becoming a DCR Supporter – which gets you behind-the-scenes videos and generally makes you awesome. With that – let’s begin!
First, just a quick run through the top-line specs, which are identical to the JetBlack Volt V2 because it’s the same hardware (something Zwift confirmed as well, there are no changes here):
– Direct drive trainer: This means you remove your rear wheel – Flywheel: It has a flywheel weight of 4.7kg – Cassette: A cassette is included, and you choose how many speeds (8/9/10/11/12) upon ordering on Zwift’s site. Which is then officially compatible with Shimano and SRAM drivetrains (unofficially, 11sp Campagnolo will also work on Shimano cassettes, just as many users do so today on JetBlack and other trainers) – Sound: Essentially silent. Only the sound of your drivetrain is heard – Handle: This unit lacks a handle, which continues to make it slightly awkward to move around – Protocol Compatibility: ANT+ FE-C, ANT+ Power, Bluetooth Smart Trainer Control, Bluetooth Smart Power (everything you need) – Unique Party Trick: Can rebroadcast your heart rate sensor within a single channel, ideal for Apple TV Zwift users (who are Bluetooth channel limited) – App Compatibility: Every app out there basically (Zwift, TrainerRoad, Rouvy, RGT, The Sufferfest, Kinomap, etc…) – Skewer Compatibility: All the skewers and adapters you could ask for: Road 130mm, 135mm, 142x12mm, 148x12mm – Max Incline: 16% simulated grade – Max Wattage: 1,800 watts resistance (or 1,300w @ 40KPH) – Stated Accuracy: < +/-2.5% – Power Cable Required: Yes, power block compatible with 100-240v – Pricing and Availability: $499USD, £449, 499EUR
Note that the unit is the same regardless of which cassette is attached. Meaning, if you can’t find stock of the 12sp version, and you don’t mind buying your own 12sp cassette, you can buy a different version (e.g. 8sp) and simply swap the cassette.
Just for context, these specs are very similar to the Wahoo KICKR CORE, which costs $899 without a cassette (figure another $50 for that). The JetBlack VOLT, when sold with JetBlack branding was $849USD, or 749EUR (though, it went for about 700EUR street price, including an 11-speed cassette). However, since the Zwift announcement, JetBlack has dropped the price of the existing VOLT to match that of the Zwift Hub (i.e., $499 in the US).
Note that concurrently though, JetBlack announced a V2 version of the VOLT. That V2 version will shortly include a new automatic calibration feature that’ll also soon be coming to the Zwift Hub, to aid in better automatic calibration. Which then illuminates what is actually an interesting twist: The Zwift Hub is *actually* a JetBlack VOLT V2, which also includes some minor case-compatibility differences, as well as the automatic calibration algorithm. Specifically, JetBlack notes the V2 includes the following differences:
[Hardware] Frame update (to avoid disc mount clashes)
[Hardware] Add Keyway system to Pully axle (improved reliability)
[Hardware] Up-spec of hardware used (improving performance)
[Hardware] Updated speed sensor and position (improves overall accuracy and performance)
[Software firmware update upcoming] Auto spin down
[Software firmware update upcoming] Improved ERG support
[Software firmware update upcoming] Improved speed of reporting
When you order the Zwift Hub from Zwift, you choose your cassette type upfront. Simply put, the cassette type is how many speeds your cassette is (that’s the one at the back on the wheel). Most newer higher-end bikes are 12-speeds, most other bikes made in the last decade are 11-speed, and prior to that a blend of 8/9/10-speed. You can literally just count how many cogs you have on your cassette to determine this, it should take you no more than 12 seconds to complete this task. Though, I find it’s useful to do this task twice to be sure.
Fast forward a few days later when the Zwift Hub arrives, and you’ll find it in the above looking box. Crack that open, and it’s packaged up with an airbag giving it a hug:
Remove all that stuff, and you’ve got all the parts, notably with the cassette already installed.
Above you’ve got the trainer, two legs, some bolts, a pile of power cables, and some rear skewer/axle adapters. Oh, and a surprisingly detailed manual.
Zwift’s aim here was to make the mounting process simple, especially if you don’t know the difference between thru-axle and quick-release, or exactly which thru-axle length you have. Thus these colorful cards – specifically the pink/purple one, and the green one.
These two cards are designed to let you figure out exactly what size thru-axle or quick-release setup you have on your bike. The upper portion is a template that just slides into the rear drop-out of your bike, allowing you to instantly see which one you have.
The back of the cards show how to insert it into the back of your bike to double-check.
Next, when it comes to assembly, the Zwift Hub makes it easy to put the legs on correctly. I know this might sound silly, but trainer companies have a (very long) history of providing two near-identical, but not identical in length, legs that should be mounted in a specific spot, but can actually be mounted backwards or in the wrong spot. Also historically, trainer companies have almost never labeled these legs. So lots of people end up putting them in the wrong spot (forwards vs backwards), either the first time, or forever. It’ll usually work this way, except, it won’t be as stable – and you might tip over down the (virtual) road.
So Zwift added color coding to the legs, as well as made it such that if you put this on in the wrong orientation, then the ‘danger’ icon will be exposed. Whereas if you put it on correctly, then the danger icon is hidden under the foot.
The installation process takes perhaps 3 minutes, and involves simply four bolts. The trainer comes with the wrench required for this.
Once you install those four bolts, it should look like this:
Lastly, you’ll do the plugging in thing. As a responsible human in 2022, I’m going to assume you know how to plug a device into a wall outlet. However, while also a human in this millennium, with a gazillion electronic devices, I’m also going to assume that down the road you’ll move this trainer around your house/garage/whatever, and then might forget which power block goes to it – given it’s not labeled. Thus, here’s the back of the Zwift Hub power block in case you need to find it again.
As I’ve been doing for many years, take the sticker that’s in the box and stick it on your power block; that way you always know it goes with this trainer. Except, the Zwift Hub didn’t come with a sticker (or, I can’t find it). So instead, I made my own from the manual
See? Problem solved:
(The best part of this is that when I send it back, that manual will still have that gap in it…)
Finally, attach your bike. This will vary depending on whether you have thru-axle or quick-release. But you can merely follow the instructions on those cards to insert the correct adapters into the side of the trainer, followed by your bike, and then skewer. The key thing to know here is that this is a direct drive trainer, meaning your rear wheel is removed from the bike. This ensures there’s no slippage, while also reducing (basically eliminating) noise.
With the bike mounted on the trainer, and it plugged in, we’re essentially ready to ride. It’s worthwhile noting that the Zwift Hub doesn’t have any folding capability, so you can’t fold it up and stash it below a bed like some trainers. Though, it’s still pretty easy to stash in a closet as-assembled if you need to.
Now, with it plugged in you may have noticed the status light on the back of the trainer. This simply illuminates to tell you that it’s doing something, but unlike some other trainers, it’s not super specific (meaning no secondary lights for connectivity type or such). To be honest, in 99.99% of cases based on my experience over the past 15 years, you won’t care about separate connectivity types. Either the trainer is working (and there’s a light), or something is all effed up and likely beyond your control anyway.
Next, some people (like myself) like to use a front wheel block. You don’t need to, but I prefer it since it keeps my wheel from meandering all over the place. There’s both static ones (like shown here), or you can use turning ones. Some of these turning ones also do steering on Zwift, like the Elite Sterzo Smart. In fact, JetBlack (who makes the Zwift Hub) has an upcoming steering block as well.
Now, before we start riding, we should double-check the Zwift app for any firmware updates. This is done via the Zwift Companion App (which is the smartphone one). You’ll see a new option for Zwift hardware, and you can check/update it there:
Additionally, it’s here you can do heart rate bridging/pairing. This allows you to pair your chest strap with the Zwift Hub, and then get pass-through heart rate, so that the trainer handles the HR connection to the app on behalf of your strap. The main/singular reason you’d want to do this is for Apple TV usage of Zwift or other apps. That’s because Apple TV has a two concurrent connection limit (plus the remote). So if you wanted to do steering in Zwift, then this wouldn’t be possible since you’d have one connection for the trainer, and then one for your heart rate sensor (leaving none for steering).
But with HR bridging, the heart rate sensor data gets funneled in the same ‘channel’ as the trainer data, so it only counts as one channel – not two. You can simply search for your HR strap in this menu and then pair to it.
With that all settled, over on Zwift (or any other app) you’ll pair up to the Zwift Hub. You’ll pair it for power source, controllable trainer, and cadence. Plus heart rate if you want to:
You’ll notice Zwift has tweaked the pairing artwork to show a Zwift Hub trainer/logo.
Once that’s done, you can basically start riding Zwift. Or you can change the Zwift Trainer Difficulty level. This changes how the game simulates gradient. The default is 50%, meaning that if you see a 10% climb on the screen, it’ll actually only feel like a 5% climb. This won’t impact your in-game speed (since that’s based on wattage), but does impact how the climb feels to your legs, and which specific gearing you’ll use.
With all that said, let’s start riding. Given the Zwift Hub is a smart trainer (as opposed to a dumb trainer), it’ll change resistance automatically in a few different ways, primarily driven by different applications/methods. But most of this all boils down to two core methods:
ERG Mode: Setting a specific power level – i.e., 220w. In this mode, no matter what gearing you use, the trainer will simply stay at 220w (or whatever you set it to). Simulation (SIM) Mode: Simulating a specific outdoor grade – i.e., 8% incline. In this mode, it’s just like outdoors in that you can change your gearing to make it easier or harder. Wattage is not hard-set, only incline levels.
In the case of simulation (aka slope) mode, the Zwift Hub can simulate from 0% to 16% incline – the same as the KICKR CORE. While other trainers can simulate above 20% these days, I continue to question how many people actually want to ride such a gradient. When I’m outside doing any road rides with more than about 12% gradient, it just sucks – let alone 14%, 16%, and more. A 24% incline? There’s just no reason I want to relive that scenario voluntarily indoors.
The second mode the trainer has is ERG mode. In that case, the company claims up to 1,800w of resistance. Although, realistically, you don’t care about that. I can only barely (maybe) break 1,000w for a second or two, and even most front of the non-pro pack cyclists aren’t going to top 1,800w. The pros would only be just a bit beyond that. Said differently: Peak numbers in this competition don’t matter. Instead, what matters is actually a harder metric to make clear – which is the ability to simulate high grades and lower speeds (especially if you’re a heavier cyclist).
One core test I do with all trainers though is responsiveness: How quickly does it respond to ERG mode changes? I typically do that with my 30×30 test via TrainerRoad, though it doesn’t really matter what method you use. For example, earlier today I did a slightly different variant of that test using Zwift. Here’s a look at a TrainerRoad one, where I’m going from 150w to 455w, over and over again:
In this case, very consistently, the trainer hit that wattage in 2 seconds. Which is pretty much right where I wanted it to be (any faster is actually too rough, and much slower than 4 seconds cuts into shorter intervals too much). Do note though that because of ERG Mode Smoothing on the Zwift Hub, there isn’t a definitive way to see whether that was actually more like 3 seconds, because it over-smooths the data. But in terms of the secondary power meter data I have, it seems to largely support the 2-second adjustment.
Note that one thing you’ll find with the Zwift Hub (if you have a secondary power meter to check it), is a little bit of drift, due to heat build-up. In my testing, as well as what Zwift themselves say – they recommend doing a spin-down calibration at about the 10-minute marker. Doing so will set the trainer back in alignment for the remainder of the ride. In the case of Zwift, you can just access the pairing menu and then the calibration option. All in, it takes just a few seconds.
Obviously, this isn’t ideal mid-race (it’s a non-starter), but then again, neither is skipping a warm-up before a race. This is somewhat back to the ‘older’ days of trainers (a few years ago). Though realistically, if you remember those days, you’ll also know that if you leave your trainer in a temperature-stable place (so…not the garage), then by and large the calibration curve remains the same. Meaning, you can pretty much get away with doing a calibration every once in a while (few weeks), because the trainer will heat-up the same way each time over those 10 minutes. The difference in my testing is about 10w (on 250w).
So what about road feel and noise?
Like I always say – for me personally, it’s hard to separate the fact that I’m riding indoors from outdoors. It’s still a trainer, and I’m still looking at a wall in front of me. My brain can only turn off so much of that. Still, much of the road-like feel is driven by the flywheel, and be it physical or virtual, flywheel sizes tend to be measured in weight. This impacts inertia and how it feels – primarily when you accelerate or otherwise change acceleration (such as briefly coasting).
The Zwift Hub has a flywheel weight of 4.7kg, which is a little bit smaller than the 5.4kg of the Wahoo KICKR CORE. However, unlike some endeavors, size isn’t everything – because flywheel weight is merely one factor – especially because it can be multiplied depending on the exact gearing internally. Nonetheless, the Zwift Hub to me feels like it’s in the same ballpark as the Wahoo KICKR CORE ($899 + cassette) in terms of ride feel. Accelerations feel good, decelerations feel good. I’m overall pretty happy and I’d have no problems riding it as my daily trainer from a ride feel standpoint.
There are other minor things that the KICKR CORE has in terms of the ride experience that the Zwift Hub lacks, such as integration with the Wahoo CLIMB, or multi-Bluetooth connections. Obviously, the CLIMB gradient simulator would enhance the riding experience, but also reduce your wallet by $700.
Finally, what about sound? It’s silent – there’s no noise except your drivetrain coming from it. So essentially, how clean you keep your drivetrain is the key factor for how quiet your trainer is. If you’ve got a nice clean chain/chainring/cassette, then your Zwift Hub will be legit silent. If it’s full of gunk/grit, then you’ll hear a (tiny) bit of sound.
With that, let’s dive into app compatibility.
The Zwift Hub properly follows virtually all of the trainer transmission and control standards in the industry today, meaning it works with not just Zwift, but any 3rd party app as well, given it follows all of these standards.
This is notable given you’d be buying a trainer from a specific trainer app brand, but realistically, I think that’s a safe bet. It’s highly unlikely Zwift would ever do anything to remove that 3rd party support. First up, it’s listed on their purchase page here (and screenshotted below), which means it’s part of the product at the time of purchase. Attempting to remove those features down the road would get them in substantial trouble in the minds of EU & UK consumer rights government bodies.
But far more importantly, and technically obvious, if you don’t update the firmware, then nothing is going to change. And the only way to do that today is via the Zwift Companion smartphone app. So if you buy this trainer, decide Zwift isn’t your game, and never open that app – then it’s not going to update the firmware.
With that, here’s the complete list of protocol transmission standards/types the Zwift Hub Supports:
ANT+ FE-C Control: This is for controlling the trainer via ANT+ from apps and head units, and includes power & cadence data. Read tons about it here. ANT+ Power Meter Profile: This broadcasts as a standard ANT+ power meter, with cadence data baked in (but not speed data) Bluetooth Smart FTMS: This is the industry standard for apps controlling the trainer via Bluetooth Smart, and includes ANT+ power and cadence baked in. Bluetooth Smart Power Meter Profile: This broadcasts as a standard BLE power meter with cadence data. Bluetooth Smart Heart Rate Profile: It passes this through from ANT+ & Bluetooth Smart HR straps.
It DOES NOT, however, support these protocols/transmissions (which trainers from Tacx and Elite do support):
ANT+ Speed/Cadence Profile: This broadcasts just your speed and cadence as a standard ANT+ Speed/Cadence combo sensor. Bluetooth Smart Speed/Cadence Profile: This broadcasts just your speed and cadence as a standard BLE combo Speed/Cadence sensor.
The above two are mostly just useful when pairing to more basic smartwatches that might not support power meters/cadence, but I don’t expect it matters to too many people.
Starting off with Zwift, as already noted it pairs up easily using either ANT+ or Bluetooth Smart. In my case, I used Bluetooth Smart via Apple TV – as I wanted to test the heart rate pass-through. You’ll see it listed as a controllable trainer as well as a power source, plus also a heart rate sensor. This is part of the benefit of it funneling in your heart rate strap data as a single data stream, it takes up one less channel on Apple TV versus pairing the strap separately (which has a limit of two concurrent channels).
Once you’ve started your workout, it’s basically just like any other trainer. Starting with SIM mode (which is the mode where the trainer changes the gradient), it responds properly within the app as I’d expect. I have my trainer difficulty set to 100% as you can see above, so I’ll “feel” all of these hills at their full painfulness. I’ve done a few different routes, but most notably the Titans Grove loop on Watopia. I’ve been using this route for a few years to test trainer responsiveness, as it’s actually a great way to see how quickly trainers can respond, plus it has a nice flat section later for some high flywheel speed testing.
Then I’ve done a pile of testing in so-called ERG mode on Zwift and otherwise, which is where the trainer is set for a given wattage – e.g. 250w. In this mode, the trainer will automatically control every step of the workout, so you won’t shift gears. You’re just along for the ride – simply keep pedaling. Ideally you’ll do this workout in the smallest front ring you have (if you have two front chainrings), as it tends to give more accurate results, specifically when it comes to hitting higher wattage targets.
Next, I also did testing with TrainerRoad, specifically using ERG mode. You can see the trainer show up here in the settings:
I had no issues completing the TrainerRoad workout, it worked as expected:
One minor downside is that the Zwift Hub doesn’t have any method to turn off so-called ERG Mode Smoothing, which somewhat artificially smooths the data during ERG workouts (making it look smoother/prettier, rather than more jagged). Most other companies either have this option, or they don’t have ERG Mode Smoothing at all. Realistically though, this mostly just impacts product reviewers like myself that want better ability to look at power accuracy data in a more granular fashion. Whereas most normal users would just prefer it look prettier.
ERG mode aside, I also did some shorter SIM mode tests with Rouvy as well (another competitor), without any compatibility issues:
Further, I successfully paired up the trainer to a slate of different watches and bike computers, using the standard ANT+ power meter transmission (which temporarily went missing back in September, but has returned for good).
This also allows you to simply control the Zwift Hub using a bike computer/watch, if you wanted to. For example to re-ride a route you’ve written (changing the gradient accordingly, or changing the wattage per a structured workout). That said, in 2022 I don’t tend to see a ton of people doing that anymore. App experiences these days are generally far better than most bike computers can deliver, and usually give better flexibility to pausing a workout midway through (to catch a doorbell/delivery), than most bike computers do. Still, the option is always there.
Ultimately, I have no real complaints when it comes to overall compatibility and integration with the Zwift Hub in terms of adopting and utilizing the standards out there. They do the same as other companies in this space. In some minor areas they exceed them (heart rate pass-through), and in others they fall a tiny bit short (ERG Mode Smoothing toggle). But on the whole, they’re in the same boat as everyone else.
As usual, I put the trainer up against a number of power meters to see how well it handled everything from resistance control accuracy, to speed of change, to any other weird quirks along the way.
In my case I used one primary bike set up in the following dual-power meter configurations:
Canyon Bike Setup: Favero Assioma Dual-sided pedals, Quarq DZero crankset Cannondale Bike Setup: Garmin Rally RS200, Shimano R9200P crankset
This is all in addition to the trainer itself. Note that because you remove the rear wheel I can’t use something like a PowerTap hub to compare as well (which I would use in power meter testing normally).
In any case, I was looking to see how it reacted in a few scenarios: Zwift (Apple TV), TrainerRoad (iPad), also earlier – Rouvy on iPad. The actual apps don’t typically matter much, but rather the use cases are different. In Zwift, with simulation mode, you get variability by having the road incline change and by being able to instantly sprint. This reaction time and accuracy are both tested here. Whereas in TrainerRoad and Zwift in ERG mode I’m looking at its ability to hold a specific wattage very precisely, and to then change wattages instantly in a repeatable way. There’s no better test of that than 30×30 repeats (30-seconds at a high resistance, followed by 30-seconds at an easy resistance). In my case I did that test both in TrainerRoad and Zwift (at varying levels).
There’s two ways to look at this. First is how quickly it responds to the commands of the application. So for that, we need to actually look at the overlay from TrainerRoad showing when it sent the command followed by when the Zwift Hub achieved that level. Here’s the levels being sent (the blue blocks) by TrainerRoad (in this case via Bluetooth Smart on iPad) and how quickly the Zwift Hub responded to it:
The main thing I’m looking for here is how quickly it responds. In this case, the Zwift Hub was completing the transition in 2 seconds (below), which is exactly where I want it (ideally 2-4 seconds). Any faster and it’s actually too fast, and any slower and you’re burning interval time. There’s also the question of stability of holding the power set point. Stability is two factors: How even I pedal, and how evenly the trainer/bike controls the power. I generally only judge a trainer on my more perfect pedaling efforts. In all these it’s a bit tough to tell, because of the inability to turn off ERG mode smoothing. On the 5th one though it’s ideal, that’s where my legs gave out from doing this workout after a run.
For fun, if we switch to Zwift, here’s a different workout where it’s still got 30×30’s (10 of them this time), but also some other intervals. It’s a bit harder in the Zwift UI to show the exact seconds, but again, it was roughly 2 seconds each time. Instead, we’ll look at how the power matches up. In this case, I did a warm-up of 10 minutes, and then started my first 1-minute interval. After that (so at the 11-minute marker), I quickly did the calibration of the trainer, which is why you see the wonk at that point, since you stop pedaling for the spindown:
That said, you can see it’s actually already stabilized/matched by the 8-minute marker above. Nonetheless, I did the calibration anyways.
You’ll notice as I get to my 30×30 intervals later in the workout that there’s a little bit of a spike there. Meaning, the ERG Mode Smoothing pretends the spike doesn’t exist on the Zwift transmission, but the two power meters tell the real story – which is that it spikes a bit high. That’s not at all unusual on many trainers, but worthy of mention. You see as I stabilize my pedaling, the two match again – and when stable, they’re within 3w (on 365w).
Next, let’s look at another ERG workout. In this one, I’m demonstrating what happens if you don’t do any calibration/spin-down. What’s fun here is we can see exactly how long it takes to warm-up. And it’s roughly the 10-11 minute marker that the Zwift Hub gradually matches the Garmin Rally pedals. That green line? That’s the Shimano R9200P, and it’s pretty much always incorrect in terms of being an offset. That’s another review unto itself, but as I’ve very clearly established over the course of the summer and now fall – it’s virtually always wrong.
In this case, this was a new unit straight out of the box with *ZERO calibration*. Roughly speaking we see a gap of about 15-20w (lower than Rally) from the Zwift hub at the very beginning, down to a more reasonable 5w lower than Rally by the time it stabilizes. Given it’s measuring lower down the drivetrain, 5w would be about right. Point being, this ride actually does stabilize itself – without any calibration (ever) whatsoever, to the correct values, by the 10-minute marker.
And for fun, I even split this entire workout in half, basically doing the first half in the small ring, and the second half in the big ring, to demonstrate no meaningful difference in accuracy here from the Zwift Hub (the variations are due to my cadence):
Speaking of my cadence, here’s the estimated cadence from the Zwift Hub, which is spot-on with the power meter’s cadence measurements. And, for all its power failings, the one thing the Shimano R9200P has, is a cadence magnet, so it’s actually correct there.
Next, let’s look at a SIM ride, this one in Zwift. You can see here where I do the calibration at about the 15-minute marker. Do note that I’m plotting both the Zwift Hub ANT+ and Bluetooth signals on the same chart (recorded on different device) – just to catch any quirks there. As always, you’ll see the second-by-second differences there just due to the inherent nature of different recording timing on different devices trying to align to a 1-second interval.
If we zoom in for fun, we can see at the 1-minute marker, we’re about 8 watts below Rally:
By the 6-minute marker we’re in the 4-6 watt range:
And by the 10-minute marker we’re within a watt (which, one could debate the merits of…but we’d be here all day):
So I then did two calibrations (as seen below, I did two because I forgot to get screenshots the first time). After which, the Zwift Hub basically floats 1-3w below Rally (great!) for the rest of the ride. Though frankly, the power had already stabilized by this point anyways.
If we look at these sprints (peaks at 900w, but the charts are smoothed at 5s, so the peak is actually higher), we’ll see they’re within 3 watts. Which, for the record – is really damn hard to do in most trainer tests. These two sprints were high flywheel speed tests (which are the most difficult for trainers to ace).
And finally, the mean-max chart for this workout, and it’s very close. The Shimano also actually does reasonably well here, as it usually does when steady-state efforts aren’t involved (or other complex things).
Ultimately, looking at the Zwift Hub, it easily outperforms virtually every other sub-$1000 trainer except the Wahoo KICKR CORE, and even then, all of my testing indicates it’s primarily those first 10 minutes that are different – and in all of my tests about 5-10 watts, with most of that aligned by minute 6-8. But of course, that trainer is almost twice the price once you factor in a cassette ($899 + a $50-$75 cassette, then tools to install said cassette if you don’t have it).
As GPLAMA demonstrates in his video review, there are some gearing edge cases later in a longer workout where overheating can also become a factor, causing roughly similar % differences to the pre-calibration areas. He then shows the same on a KICKR CORE, and while it too is off, it’s not off by as much. Realistically, most trainers have quirky power gap spots in them, it’s often a matter of finding them. We saw this when the Wahoo KICKR V5 was launched, with some major gaps that was closed 5-6 months later. Same goes for the Tacx NEO 2T series in ERG mode.
In the case of Zwift, they plan to introduce (shortly) an auto calibration routine that aims to keep things closer, especially during those first 10 minutes. I suspect this will work, since for the most part you can only generate so much heat in the first 10 minutes of the ride. However, this might be more tricky in longer rides (e.g. over an hour), where more heat can build up, as the Zwift Hub doesn’t have an internal temperature sensor. But this is hardly unchartered territory. Plenty of trainers do these sorts of calculations quite well, and so we’ll have to see how things shake out.
[Update: As of May 2023, the temp compensation feature has been added, and I’ve done validation that it solves it. Here’s my post on that.]
Still, for 90%+ of riders, I suspect this trainer hits the mark as-is already in terms of accuracy needs.
(Note: All of the charts in these accuracy sections were created using the DCR Analyzer tool. It allows you to compare power meters/trainers, heart rate, cadence, speed/pace, GPS tracks, and plenty more. You can use it as well, more details here.)
I’ve added the Zwift Hub into the product comparison database. This allows you to compare it against other trainers I’ve reviewed. For the purposes of this particular table, I’ve compared it against the Elite Suito, Tacx Flux S and Wahoo KICKR CORE, all of which are the mid-range trainers from each company. You can also mix and match and create your own trainer comparison charts with just about any trainer on the market in the aforementioned/linked product database.
Zwift deciding to partner with JetBlack for the VOLT was one of the smartest decisions they could have made, hardware-wise, in terms of finding a reasonably solid trainer, and then dropping the price a bunch to try and get more people on the platform. In terms of ease of use, setup, and the entire unboxing/first ride experience, it’s very well done. They’ve done some little things around the thru-axle adapters and such that really do make a difference if this is your first time dealing with a smart trainers.
In terms of the durability of the hardware, the existing VOLT hardware/unit has more than proven itself to be a good choice long-term, with me seeing virtually no customer complaints on my previous reviews. And anything else that pops up the company has fixed quickly. That’s notable because as much branding as Zwift has thrown at this, this remains a partnership between Zwift and JetBlack, and ensuring you’ve got a good partner is key – especially for longer-term updates and tweaks.
Which, like anything, isn’t to say it’s perfect. Obviously, we’ve discussed the warm-up calibration bits, though I think it’ll also be over-discussed. Every trainer under $800 has far greater calibration/warm-up/accuracy issues (relatively speaking) than the Zwift Hub. And it’s only when you get to a $900 trainer (Wahoo KICKR CORE, plus more for a cassette) that you can find something that just barely edges it out. The bigger reason to buy a Wahoo KICKR CORE isn’t the accuracy – it’s the integration with the Wahoo KICKR CLIMB.
And that all mostly sidesteps the most obvious thing: Zwift doesn’t really care at that point if you buy a KICKR CORE instead. Their goal here isn’t to make meaningful amounts of money on trainers. Their goal is to sell and retain Zwift subscription and its recurring revenue, especially to newer cyclists to the virtual realm. That’s *the entire point* of the Zwift Hub.
And to that end, I think Zwift’s done a really good job of striking the right balance in offering a product at a fantastic price point that bats well above every other trainer in that price ballpark.
With that – thanks for reading!
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Hopefully you found this review useful. At the end of the day, I’m an athlete just like you looking for the most detail possible on a new purchase – so my review is written from the standpoint of how I used the device. The reviews generally take a lot of hours to put together, so it’s a fair bit of work (and labor of love). As you probably noticed by looking below, I also take time to answer all the questions posted in the comments – and there’s quite a bit of detail in there as well.
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I use Apple TV for Zwift the vast majority of the time, but also just for watching YouTube/Netflix/etc on the trainer. The Apple TV remote sucks though. This $8 case fixes that, it's a silicone strap that makes it easy to grab, but also has a strap to easily place on the edge of your handlebars. Boom! Note: Not compatible with 2021 Apple TV Edition.
Here's the thing, some people like front wheel blocks, some don't. I'm one of the ones that do. I like my front wheel to stay put and not aimlessly wiggle around. For $8, this solves that problem. Note some trainers do come with them. Also note, I use a riser block with *every* trainer.
I've got three of these $12 fans floating around the DCR Cave, and I frequently use them on rides. They work just fine. Sure, they're not as powerful as a Wahoo Headwind, but I could literally buy 20 of them for the same price.
This desk is both a knock-off of the original KICKR Desk, but yet also better than it. First, it's got wheel locks (so the darn thing stays put), and second, it has two water bottle holders (also useful for putting other things like remotes). I've been using it as my main trainer desk for a long time now and love it. Cheaper is better apparently. Note: Branding varies by country, exact same desk.
This is by far the best value in trainer desks, at only $59, but with most of the features of the higher end features. It's got multi-tier tablet slots, water bottle holders, non-stick surface, adjustable height and more. I'm loving it!
One of the most popular trainer fans out there, rivaling the Wahoo Headwind fan in strength but at a fraction of the price. It doesn't have smartphone/ANT+/Bluetooth integration, but it does have secondary outlets. I've been using it, and a similiar European version lately with great success (exact EU variant I use is automatically linked at left).
I've had this for years, and use it in places where I don't have a big screen or desk, but just an iPad or tablet on my road bike bars.
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Thanks for reading! And as always, feel free to post comments or questions in the comments section below, I’ll be happy to try and answer them as quickly as possible. And lastly, if you felt this review was useful – I always appreciate feedback in the comments below. Thanks!
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Think my written reviews are deep? You should check out my videos. I take things to a whole new level of interactive depth!
Smart Trainers Buyers Guide: Looking at a smart trainer this winter? I cover all the units to buy (and avoid) for indoor training. The good, the bad, and the ugly.
You probably stumbled upon here looking for a review of a sports gadget. If you’re trying to decide which unit to buy – check out my in-depth reviews section. Some reviews are over 60 pages long when printed out, with hundreds of photos! I aim to leave no stone unturned.
I travel a fair bit, both for work and for fun. Here’s a bunch of random trip reports and daily trip-logs that I’ve put together and posted. I’ve sorted it all by world geography, in an attempt to make it easy to figure out where I’ve been.
The most common question I receive outside of the “what’s the best GPS watch for me” variant, are photography-esq based. So in efforts to combat the amount of emails I need to sort through on a daily basis, I’ve complied this “My Photography Gear” post for your curious minds! It’s a nice break from the day to day sports-tech talk, and I hope you get something out of it!
Many readers stumble into my website in search of information on the latest and greatest sports tech products. But at the end of the day, you might just be wondering “What does Ray use when not testing new products?”. So here is the most up to date list of products I like and fit the bill for me and my training needs best! DC Rainmaker 2023 swim, bike, run, and general gear list. But wait, are you a female and feel like these things might not apply to you? If that’s the case (but certainly not saying my choices aren’t good for women), and you just want to see a different gear junkies “picks”, check out The Girl’s Gear Guide too.