Product Review: Tacx Flux Indoor Smart Trainer

As my first non-bike product review on this blog, I’m going to be trying out a style, but that style might change as I write a few more posts. I’ve bought some cool things lately and have been putting them through their paces in order to try and get some nice reviews out over the coming weeks and months. The first product up is the Tacx Flux Indoor Smart Trainer.

Why Did I Want the Product?

The weather in Alabama is certainly not the worst, but it can still get a little grim at times during the winter. Last season I braved the weather fairly well and got some good base miles, all outdoors. The real issue last season was trying to fit in training rides once classes and race season were in full swing. I thought that an indoor trainer could help with this and it would also give me another option when the temperatures and weather got worse.

I decided to buy the Tacx Flux because it was the cheapest wheel-on smart trainer and after reading/watching a few other reviews, I couldn’t find any reasons as to why I shouldn’t buy the cheapest option. I wanted a wheel-on trainer so that I wouldn’t have to worry about tire wear and I could keep the noise down since I live in an apartment with closer neighbors and two other roommates. Also, if I was going to get a trainer to train indoors, I wanted to get something good enough to really enjoy my time and not just feel like I was staring at a wall all winter.

Initial Thoughts

I spent my first ride on the trainer as my first Zwift ride as well. The setup was really easy as I just had to plug in an additional ANT+ dongle to my computer, create a Zwift account, and then quickly pair the trainer, my power meter, and my heart rate monitor to the game. The first thing I noticed was how much more difficult it was to spin up the trainer, and as I continue to ride that is definitely the case. I wasn’t expecting a “real world” feel in every aspect, and this may be an issue with most trainers, but I really didn’t expect to have to feel like I was grinding a big gear just to get going on the virtual road.

Once fully up to speed, the trainer certainly feels nice. It’s quiet and feels really sturdy for being a solid unit with no features that are supposed to allow rocking. Under normal riding (~200 watts) the trainer sways side to side sort of like a normal bike would, but doesn’t at all feel like it’s about to tip over and there’s almost no creaking or other worrying noises.

What I Like About the Product

After almost a month of using the trainer for a few rides a week, it’s done its job so far. Riding outside is still superior, but for the days where I don’t get off work until after dark or when the rain is falling, this trainer paired with Zwift still makes it bearable to get a decent ride in. I wouldn’t try to replace my outdoor rides with this trainer, but with the help of Zwift and YouTube, I did manage to do a few 3 hour rides inside, which is certainly something I couldn’t say about my rollers.

While workouts on the trainer seem to feel harder than outdoor workouts, it is nice to be able to just hop on the trainer and know I can ride at my required power for the required time periods without having to think about an outdoor route. The erg mode seems a little aggressive at times, but the extra motivation to hold a certain power number for a duration of time makes it a little easier to get through a workout on my own.

Granted, most of the things that this trainer does well could probably be said about any other smart trainer, it’s nice to get these features in just the cheapest wheel-on smart trainer on the market right now. That alone makes this product worth if for me, as of now.

What I Don’t Like About the Product

Here’s where things go a little south. Some of these things I thought were my fault at first and some still might be things that I’m doing wrong. Regardless, they still happen and they’ve made the use of the trainer less than ideal.

First, I can’t for the life of me seem to get the gears on the trainer to work like I feel like they should. I opted to put the same exact cassette on this trainer that I have on my bike normally (11-32t, Shimano 105 11-speed), and I still have issues with the shifting in almost every gear combination except for a few. I thought it had to do with possibly not tightening the cassette properly, but after taking the entire thing off and re-assembling it and making sure to tighten it down to specifications, I still have the same issues. When on my actual bike, I have almost perfect shifting, but when I hop on the trainer, it’s almost like only 3-4 of my 22 gears actually want to work. The derailleur will almost seem to sit in between so many gears and will either make a noise the entire time or jump up and down the cassette based on how much power I put through the pedals.

The instructions that came with the trainer said I didn’t need to add a spacer for Shimano cassettes, but it seems off that my gears would be so out of index when they theoretically should be the exact same as they are on my actual rear wheel. This issue then brings about more issues, especially when trying to ride at a set wattage for a workout. I basically am forced to find the one close gear that works and then hope that cadence is good enough or wait for erg mode to take over a make things a little bit better.

Most of my first rides were just basic endurance rides where I was riding at about the same wattage for the entire ride so that gearing issue wasn’t the end of the world. As soon as I began to do some sweet spot workouts on the trainer, the gear selection becomes more important, and therefore this issue seems even bigger. When I’m doing an effort, especially longer ones, I like to be able to switch between lower cadence and higher cadence throughout the effort in order to switch the “pain” between my lungs and legs even if it only makes a small difference. With this gearing issue, I don’t have much of a choice and often have to ride the full 10-15 minute effort at either a lower or higher cadence than I would normally prefer.

I’ll continue to look around for some sort of solution to this problem, but I really don’t want to have to resort to indexing my gears each time I switch my bike to the trainer.


As the cheapest wheel-on smart trainer from a reputable company, I still think I’d recommend the Tacx Flux Indoor Smart Trainer to others. Until I get the chance to ride one of the nicer trainers to see if they are better in the areas I’ve complained about, I don’t see a reason not to suggest this trainer at this price, especially if you can find it on sale like I did.

The gearing issue is quite frustrating, but the erg mode usually kicks in and makes it bearable for whatever gear I seem to get to work. Workouts and riding are still manageable to do, but having an actual selection of gears would only give this trainer more of a realistic ride, which would really be nice as I plan to do much more of my build workouts later in the spring on this trainer.