Tacx Flux S Smart Direct Drive Trainer
Effectively a minor refresh of the original Tacx Flux, aims to deliver a quality direct-drive experience at the lowest possible price point. It shouldn't be confused with the higher-priced and higher-spec'd Flux 2.
Key Specs
- MSRP: $749 USD
- Accuracy: +-3%
- Flywheel: 15lb
- Max Wattage: 1500 W
- Max Incline: 10%
Where to Buy
More Details
- Brand: Tacx
- Year Released: 2018 (In Production)
- Axle Compatibility: 130/135mm quick release, 12x142 and 12x148 thru-axle
- Requires Calibration
- Weight: 21kg
- Cadence: Built in
- Communication: ANT+ and Bluetooth
- Cassette Included: No
- Physical Dimensions: 26" x 25" (66 cm x 63 cm)
Support App: Tacx Training
The Tacx Training app can be used to upgrade the firmware on your Tacx trainer, as well as calibrate any Tacx trainer that requires calibration. It’s also a training app, with films to ride through and structured workout capabilities.
Overall Rating
3.9 stars
based on 36 reviews
During the corona period I decided that something had to be done about me sitting around so I started looking into indoor trainers. A cheap direct drive unit was decided upon and following a recommendation from a friend the Tacx Flux S was ordered and set-up. The set-up was super simple and with a new Tacx usually comes a free month of Zwift so I was ready to go in no time. From March to September this trainer gave me a lot of joy and I was joining rides 4 days a week on average, I could go all out in sprints and never reach the end of the power (1275W 3 sec max), ride my first really long ride 100KM+ and climbing mountains was something I liked to do, despite being a heavier rider (100kg+). This was the reason to look for an upgrade to a mid level trainer as there are very, very few climbs beyond the 16% or 17% mark. The first time on one of these was an absolute hell as the difference between 8,9,10% and more are now really hurting but that's what I wanted anyway 😉 
lovely starting trainer if you’re not into high climbing from Rick V September 26, 2021Â
But after a while I was wondering how I could climb the Ven-top or the Alp du Zwift without using my smallest gears and that's where the limitations of the budged direct drive trainers comes in. On the box it says that it can handle 10% incline but in reality I didn't feel any difference between 7% and 10%. I don't know if this was due to my weight but also after multiple calibrations the resistance didn't change beyond that one point.
Bought the trainer, thought will be great for my Canyon CF Disk (didn't mention that it was not compatible) which has through axel frame. Had to research how the hell I can fit it on. Found a tutorial on Zwift youtube lol - I needed an adapter. Tacx Smart Flux S doesn't come with one as it turns out, only Tacx Smart Flux s 2 comes with one. (makes no goddam sense) Now I have to order a 60 euro adapter, which is not available anywhere, making this trainer useless. Reached out to Tacx for help, 1 week later haven't had any proper reply as to what I should do... They should have discontinued version 1, to be honest. Looks well built though, so if one day I get an adapter maybe I can say how it works. 
Newer bikes not compatible, doesnt say that anywhere. from emils.lukasevics February 17, 2021Â
I have had multiple warranty replacements. One time for faulty bearings, once for constant disconnects (the unit got overheated), and finally again, for overheating. Sadly, every unit took 1-2 months to arrive. The trainer would have been a perfect entry-level one if the quality would be a little bit better.
Got replaced multiple times, opt for Wahoo or Elite instead from tamas_sz December 13, 2020Â
I do think its specs are "enough", especially if you are a lighter (sub 75-70kg) rider.
Bought this while it was on discount at Wiggle in December 2018, to replace a Tacx Flow. Have had no problems at all using it a lot, mostly with Zwift but also tried several other options all of which worked fine - but I still find Zwift the most motivating. Don’t seem to need to calibrate much, maybe once a year, and the power data is close to my old Tacx Flow, and very close to my Shimano 9100 power meter. As another reviewer commented, it is a tad noisy for the first few minutes, though my fan is louder, and anyway the noise disappears once it (and I) have warmed up. No problems in 2 years of use. from Westy November 25, 2020Â
If this trainer could pair with Zwift, it would be great. Unfortunately, it only appears visible in the proprietary app from TACX. It can't be seen by Zwift. That makes if absolutely worthless as a platform for Zwifters. I can only still use Zwift by pairing my bike's power meter. If I had known that this was a giant flywheel only with no ability to pair online, I would have just gone with a fluid trainer. Doesn’t Pair With Zwift from matrose617 October 13, 2020Â
More Tacx Flux S Smart Reviews
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During the corona period I decided that something had to be done about me sitting around so I started looking into indoor trainers. A cheap direct drive unit was decided upon and following a recommendation from a friend the Tacx Flux S was ordered and set-up. The set-up was super simple and with a new Tacx usually comes a free month of Zwift so I was ready to go in no time. From March to September this trainer gave me a lot of joy and I was joining rides 4 days a week on average, I could go all out in sprints and never reach the end of the power (1275W 3 sec max), ride my first really long ride 100KM+ and climbing mountains was something I liked to do, despite being a heavier rider (100kg+). This was the reason to look for an upgrade to a mid level trainer as there are very, very few climbs beyond the 16% or 17% mark. The first time on one of these was an absolute hell as the difference between 8,9,10% and more are now really hurting but that's what I wanted anyway 😉 lovely starting trainer if you’re not into high climbing from Rick V September 26, 2021Â
But after a while I was wondering how I could climb the Ven-top or the Alp du Zwift without using my smallest gears and that's where the limitations of the budged direct drive trainers comes in. On the box it says that it can handle 10% incline but in reality I didn't feel any difference between 7% and 10%. I don't know if this was due to my weight but also after multiple calibrations the resistance didn't change beyond that one point.
Bought the trainer, thought will be great for my Canyon CF Disk (didn't mention that it was not compatible) which has through axel frame. Had to research how the hell I can fit it on. Found a tutorial on Zwift youtube lol - I needed an adapter. Tacx Smart Flux S doesn't come with one as it turns out, only Tacx Smart Flux s 2 comes with one. (makes no goddam sense) Now I have to order a 60 euro adapter, which is not available anywhere, making this trainer useless. Reached out to Tacx for help, 1 week later haven't had any proper reply as to what I should do... They should have discontinued version 1, to be honest. Looks well built though, so if one day I get an adapter maybe I can say how it works. Newer bikes not compatible, doesnt say that anywhere. from emils.lukasevics February 17, 2021Â
I have had multiple warranty replacements. One time for faulty bearings, once for constant disconnects (the unit got overheated), and finally again, for overheating. Sadly, every unit took 1-2 months to arrive. The trainer would have been a perfect entry-level one if the quality would be a little bit better. Got replaced multiple times, opt for Wahoo or Elite instead from tamas_sz December 13, 2020Â
I do think its specs are "enough", especially if you are a lighter (sub 75-70kg) rider.
Bought this while it was on discount at Wiggle in December 2018, to replace a Tacx Flow. Have had no problems at all using it a lot, mostly with Zwift but also tried several other options all of which worked fine - but I still find Zwift the most motivating. Don’t seem to need to calibrate much, maybe once a year, and the power data is close to my old Tacx Flow, and very close to my Shimano 9100 power meter. As another reviewer commented, it is a tad noisy for the first few minutes, though my fan is louder, and anyway the noise disappears once it (and I) have warmed up. No problems in 2 years of use. from Westy November 25, 2020Â
If this trainer could pair with Zwift, it would be great. Unfortunately, it only appears visible in the proprietary app from TACX. It can't be seen by Zwift. That makes if absolutely worthless as a platform for Zwifters. I can only still use Zwift by pairing my bike's power meter. If I had known that this was a giant flywheel only with no ability to pair online, I would have just gone with a fluid trainer. Doesn’t Pair With Zwift from matrose617 October 13, 2020Â
Other than an old wheel on trainer I don't have anything to compare to but I am happy with my purchase. Only issue I occasionally have is that if I get off my bike (forgot to turn fan or get towel etc) and then come back to it I often get 'No Signal' on the turbo on Zwift, not sure what the cause is. Seems Decent – Would Recommend from Quixotic22 September 30, 2020Â
I'm 1.96 meters and weigh >94kg's, this device handles my efforts perfectly. Just recalibrate once in a while, install and usage during the last 9 months were perfect. Great device to keep in shape. from W.ilfred September 29, 2020Â
Great trainer on a budget, calibrating every week is a little annoying but not too hard to live with. Very happy with it! Great budget trainer from jessa September 27, 2020Â
Excellent budget trainer. It's a tad slow on the changes in ERG-mode, can sometimes struggle to reach higher resistance when in lower gears and it's not the most storable. Best to avoid with thru axles as the adapter doesn't seem to fit all frames. It will get you 95% of the experience for a lot less money than the top end models. Great trainer for most from RL September 27, 2020Â
The price is attractive, the build quality is spot on, the updates are seamless. It lacks slightly in reaction time and I have no comparison regarding road feel, but I'd recommend it to anyone as a 'budget' direct drive trainer. Affordable quality from ronanmac September 26, 2020Â
Good trainer from TomKacz September 25, 2020Â
Easy setup Accurate power Realistic inertiaWell-built Helpful support Quiet Budget-friendly
Large improvement from my past wheel on trainer. I did have an issue where the flywheel was making a grinding noise but after contacting support they had a new one sent within days. Tacx Flux S Smart from Topiary September 23, 2020Â
This is my first smart trainer and I chose it for its price tag. I use it with my 26“ Mountainbike, a QR-axle and a 9 speed MTB cassette from SRAM. Cassette assembly was no hassle as I have done this quite often in the last 20 years, to a complete newbie to biking or a not so tech-savvy biker this could be a bit of a problem. But I think this applies to the vast majority of trainers.
All you need for starters from coffeeholic September 22, 2020Â
As my FTP is just around 200W and my racing ambitions on Zwift are humble I don‘t care that much for the most precise measurement and the most brutal braking capabilities. What I do recognize is a slight delay in inclination changes or ERG-mode wattage changes in workout mode of about a second.
This thing weighs a ton and it feels bombproof, but it is quite chunky and not easy to put away in the living room as the legs do not fold. You could always unscrew them and put them back on the next time, but this would be quite a hassle.
My connection is via BT to an AppleTV and I never experienced a dropout, I can‘t say anything on ANT+.
This trainer has a solid base and is easy to setup. It is affordable and the max 10% hill grade is sufficient for most rides on Zwift Solid trainer from JohnnyBee September 17, 2020Â
I switched six months ago from the Bkool Smart 2 to this Tacx, looking for something quieter and more realistic when pedaling. Undoubtedly those are the two characteristics that I would highlight the most of the Flux S. The smooth rolling and low noise level are appreciated when occupying shared or little noise insulated spaces. Against, something heavy and what can be a limitation for some regarding the power, inertia and simulated slope A real budget friendly direct drive smart trainer from KoneX September 16, 2020Â
Been racing the Flux S for a year. Very decent machine. Works very well in Zwift, but you will notice the lack of "muscle" on the steeper inclines. Same goes for ERG-mode: Super-good on intervals longer than 30 sec and not too much torque, but struggles on swift resistance changes and very high power/slow speed intervals. Very good entry-to-intermediate trainer from oellgaard September 16, 2020Â
So all in all a great choice for the less experienced/less powerful riders I would say up to mid B-level riders.
From the moment of unboxing (and sourcing a cassette) this trainer has just worked. Able to handle more watts than my feeble legs can produce this is now a permanent fixture in my pain cave / living room. When something goes wrong with technology before or during a workout, it becomes really disruptive so it is nice to have something I can rely on. Value and reliability from BigWazofOz September 16, 2020Â
So easy to set up and easier to use. No roll down, no calibration, just works - every single time. I researched all available smart trainers in this price point a year ago to replace a CycleOps that I owned for several years that was lost in a flood. I made the right choice for me. Owned for a year and still love it! from BillyMc September 15, 2020Â
A good trainer from quandra September 13, 2020Â
Easy setup Accurate power Well-built Quiet Budget-friendly
Switching from on-wheel to Direct drive from mazafra September 9, 2020Â
Easy setup Accurate power Realistic inertiaWell-built Quiet
Solid trainer, getting a bit on the loud side on startup but quite after warms up. Had it for 2 years; happy with it. tacx flux s from barryo September 9, 2020Â
This has been a solid trainer that is accurate, or at least consistent with, my Garmin vector 3s. Now that Tacx is owned by Garmin, support is good. I typically aim for their products knowing if I have a problem, they'll work with me, even up to replacing the whole device if they have to (having had several Garmin FR's replaced). It doesn't provide forward inertia, so rolling down hill, but everything else seems pretty realistic; good road feel. I have had several wheel on trainers and its nice to have a spare cassette on this trainer to quickly swap from road to trainer. I've run this trainer with both skewer and thru axel with the supplied kit; both work just fine. Tacx Flux S Review from thomasail September 9, 2020Â
Bought almost two years ago, as was a good deal at Halfords using British Cycling discount. Initially I was a bit apprehensive about the Flux, as there seemed to have been a lot of warranty issues with the original version, but hopefully they had ironed them out with the updated model. Also, they'd tweaked the design to fit long-cage rear derailleurs. Generally happy from Dave W September 8, 2020Â
Easy set up and connection to Zwift, and 95% of the time calibration works first time. Occasional loss of connection before a Zwift race, but usually fine now that I've tweaked the set up. Consistency of power against a Stages PM is reasonably good considering it's a lower-end smart turbo, certainly reliable enough for racing. Gradiant-based resistance isn't massive, but personally not an issue, as I don't tend to ride that steep gradiants anyway. Similarly top power isn't great for big sprinters, but at 68kg, I don't often trouble the top end of its capabilities.
My only slight issue would be the noises it develops over time- after about 6 months, it started groaning under high resistance- usually faded away when warmed up, but I thought this was the start of the well documented warranty issues. I didn't want to be without a turbo while I sent it back and waited for a new one, so opened it up myself and did some basic maintenance- checked the belt, sprayed on some silicon spray, etc., and it was fine after that for another 6 months or so. From reading around, I understand you can replace the belt quite cheaply, so I now that it's out of warranty, I may do it myself next time it becomes an issue.
Generally though, it just does what it's meant to- probably not the heaviest use, though- approx 5 hours per week, maybe a bit more in winter.
It's a pretty good value smart trainer, fairly accurate against my crank based power meter. However, it works better with an ant+ dongle than Bluetooth (less drop outs and faster response) and can get abit noisy and squeaky at times, I also wish it could fold down for easier storage, but it can't. Overall, i'm quite satisfied with it for training and racing on zwift.
Tacx Flux S from darrendq September 8, 2020Â
I have read a lot of bad press surrounding the Flux trainer so wanted to give the perspective of someone who bought a Flux S and received it in May 2020. My unit is super quiet and feels very sturdy with the heavy flywheel although when you get out of the saddle and put a lot of power through the pedals it does have a tendency to feel a little unstable and wobble on it's stand. The inertia feels very good and the climbing steep gradients feels realistic to me. I've never had any connectivity issues either, bluetooth connection has been rock solid. The only issue I do have and it is quite a big one is that ERG mode doesn't seem to work in Zwift for me, it removes all gradients but the watts are not clamped in any way it is just freewheeling which makes it impossible to do a workout. I would normally return a product with an issue like this but on reading the reviews from people's experience with support and having to wait 2-3 months for a unit to be fixed or replaced I decided that it was something I could live with. Great trainer but not without faults from JonBloomer September 8, 2020Â
I love this trainer; never had a problem with it in many hours of riding this past winter. Out of the box setup and go. I only wish I was smart enough to have my wife's bike on the same cassette size as mine. Then we could swap bikes more easily. I have Garmin cadence & speed sensors, a garmin HRM and a wahoo tickr and would interchange a microsoft surface pro 4 or an Ipad for the interface. No problems with the peripherals and zwift. Many times I would ride with zwift and either my Garmin Fenix 2 or the wahoo element. Often times they matched exactly. Optimal Shape at the start of season from RGamperl September 8, 2020Â
This trainer offers a lot for it's budget friendly price. It has a quite large flywheel and has a stable build. My bike fits just fine and is easily placed/removed from the trained. Also, no block is needed under the front wheel. As an entry model I really enjoy using it and you get to enjoy all the features from Zwift. Having said that, there are some minor inconveniences, that may or may not bother you: Although all these remarks sound quite negative, you must see it relative to the amount of money you spent. Especially for the budget its a great smart trainer and I've used it every week since I purchased it. Budget friendly smart trainer that gets you started just fine from Blommetje92 September 8, 2020Â
- Max 10% gradient (70 kg rider), so you can't experience all Zwift hills fully realistically
- The inertia and response to pedal strokes is not super realistic. I find that especially on hills, the resistance is too low.
- ERG mode does not work without shifting. It holds the target wattage well, when you are in the right gear. E.g. low gear for low wattage.
-The trainer starts making a lot of noice and vibrations at higher Wattage. My downstairs neighbours know when I'm sprinting for the finish in a Zwift race
- Trainer legs are not foldable in any way, so storing is inconvenient.
Rock solid performer, ridden over 5,000 km and climbed over 75 thousand meters on Zwift and never dropped a beat. It may not simulate super steep gradients like it’s more expensive cousins but that certainly does not impact the Zwift experience! Training in erg mode is faultless. I pair it to an apple tv running Zwift with no issues Workhorse from Baker_e1 September 8, 2020Â
Really happy with My Turbo from Richmond September 8, 2020Â
Easy setup Realistic inertiaWell-built Helpful support Quiet Budget-friendly
Have it 2 years 150hrs riding time on zwift - going very well Flux smart S from Dave September 8, 2020Â
Very happy with trainer for price point, it is accurate quiet and offers all smart features including ERG. However it is extremely heavy and bulky and does not fold away.Also needed by but a thru-axel adaptor Good mid range smart DD. from Georgeahill90 September 8, 2020Â
Whilst this is my second Flux S (the first was replaced on warranty) I have had few problems with it since. It's easy to set up and pair with Zwift and fits medium to long cage derailleurs. I have little to compare to but the power reading seems accurate and consistent. There is some lag between Zwift and the trainer but that may also be down to my IT equipment. It's stable but heavy so not easy to move about. Overall I'm very happy with it. A good, mid budget trainer from dan_saitek September 8, 2020Â
This is a good trainer and I’m very happy with it so far. Good direct drive trainer from raphael24 September 8, 2020Â
It is extremely heavy and bulky and does not fold away.
It seems to be accurate and consistent and erg mode works well.
It is also fairly quiet - when your drive train is clean and lubed.
It is also one of the cheaper direct drive smart trainers.
Tacx/garmin were pretty slow at responding when I had questions for them.
I got this on sale, for $800 CAD, so it was a screaming good buy. It's the first trainer I've had, so I don't have anything to compare it with. It was easy to connect to devices, both to my iPad and to my Apple TV, to collect power and cadence. I get my heart rate data through the Zwift companion app and my Apple Watch. The only fiddly part of the setup was that the trainer doesn't come with a cassette. I had to remove the cassette from my bike wheel and install it on the trainer. I've since bought an extra cassette, so I can have one on the wheel and one on the trainer, allowing me to switch the bike over more easily. This unit has a lower max power capability than the higher-priced Taxc units, but as a middle aged, average cyclist, I can't even approach the power limit of the trainer. I don't feel at all constrained. I also understand that this unit can only simulate a 10% maximum grade, but it feels like plenty to me. This has allowed me to do everything I want to do in the Zwift world, and my fitness level has gone through the roof since I started using it. The only reason I would think of replacing it is if I wanted to buy a second trainer so my wife could ride at the same time as me. I guess if I had one criticism, it is that when I get out of the saddle for a hard sprint, I sometimes feel like I could knock the thing over and crash in my basement if I'm not careful. But that hasn't happened yet, and I'm not sure it would be any better on any other trainer, since I haven't tried any. Good trainer, does everything I need! from Duster929 September 8, 2020Â
Bought this because I got tired of the previous dumb trainer, wahoo blue, zwift combo during lock down. Main reason for choosing the tacx was the low price together with very decent reviews on functionality and value for money. Haven't regretted it at all. Good fun on zwift, has been working without complaints for over 2000 km now. Climbing and sprinting feels real enough. Reasonably quiet, easy to link and worked fine with several apps. Good choice for those who don't want to spend a lot yet enjoy an immersive experience and don't care super much about power accuracy. Tac Flux S Smart, great choice for the budget minded from KaiS September 8, 2020Â
ERG mode is very difficult, needs to match gearing to certain watts and cadence and didn’t find the feel all that nice. Not the greatest! from GlennK September 4, 2020Â
Power was reasonably accurate. Quiet trainer