4iiii Fliiiight Smart Trainer

DC Rainmaker

SMART Bike Trainers

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ah, the 4iiiiiiiiiiii STAC. I got mine on their STAC clearout. I’ll be interested to see what , if anything is different here

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  • Now it comes assembled. So no need to figure out the spring pins and magnets positions.
  • No spoke magnet to detect movement. Instead, they are using an optical sensor to detect spokes movement. It also has an auto-centering so you can just attach the bike to the trainer and just ride.
  • Dual Bluetooth channels.
  • They also talked about enhancing the “virtual inertia” and per my conversation with them, you might not need to use the weights. However, I am a little skeptical with that claim. I. am sure Ray will get to try it at the show or possibly he got one already.
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I just looked at the link. It definitely looks cleaner and less school project. Virtual inertia, hmmm


That looks… pretty good. As long as you’ve got aluminum rims it looks like it addresses most concerns people have had with the STAC.

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Full review is up:

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Anyone have thoughts on the unit? I’m seriously considering it and the ftp issue wouldn’t matter much for me. I’m prioritizing quiet and low vibration because of a downstairs neighbor…

If quiet is a priority and this is anything like the Halcyon, it really is nearly silent, just chain noise and with any kind of mat underneath, no vibration issues to worry about.

Have never used any 4iiii products but I have the utmost respect for their product namiiiiing strategy.


If the firmware update allows for FTPs of around 250 watts I will get myself one.
Not necessarily for the high end stuff but rather for endurance rides. Love the idea to get them in early in the morning before work. My Neo is just too loud for that.

I’m surprised that they say it’s limited to athletes with FTP of 200 or even 250. I have the Halcyon and FTP of 250 and I have had no problems in TR SSBLV or GPLV or Zwift racing. If it is not significantly worse than the Halcyon, I suspect that you are fine with much higher higher FTP than 250, if you are willing to tweak with the magnet positioning settings a bit. That being said, it will not be the best option for sprint training if you have a decent sprint.

This 250W FTP limitation reminded me of time I trained on Tacx Antares rollers (Virtual power).

That winter I got used to 110 rpm as normal cadence, but ruined my trainer tires by running ~70 psi pressure for increased resistance (tires developed some sharp edges which worn through inner tubes in 2 rides).

Would not recommend such compromise to anyone, I hope resistance is not that low.

Example: https://www.trainerroad.com/career/papuass/rides/200465-haeckel

I have the Stac halcyon and would like to share my experiences. It has always been very well tested and I am also very satisfied. My FTP is at 250w but I haven’t noticed any problems with the smart trainer. Wondering why this should be so with 4iiii. The Stac always ran very well. But what definitely speaks for the Stac / 4iii is the customer service. They are top class. I’ve had contact three times and I’ve been helped directly every time. Once the device was exchanged (I received a return instead of a new one, was a mistake by their european distributer) Then a Youtube video was made especially for me to show me the setup process and at the last contact only two weeks ago a personally built website was made for me to update / restart the software. In short: Yes, there may be better, more accurate or more powerful models, but they won me over by the service alone. As long as I´m not a pro rider with an ftp at 400w I`m really happy with them. And with my age at 38, I´m pretty sure it will be a long time :smiley:

Even at an ftp of 400 if you are in Big front and little back you should have no issues follow a TR plan in ERG. I’ve got the Haylcon and have no issue cranking out the Watts. Talking with Shane and the crew at 4iiii in ERG mode just keep the rear wheel speed up (big and small) with Fliiiight and you will be flying.

Where Ray is having issues is when you want to play in zwift. When zwifting you change gears just like on a road bike.

Zwfit is the complicated beast. You need to shift gears and there are some next level math calculations that are done based off of your body weight rear wheel speed and terrain to approximate how much power you have to put and thus how hard you must spin the rear wheel to move in the virtual world. (next level math here :wink: or just force X speed ) Now this is the issue. If you have to output a high power but move the rear wheel slowly (climbing a big hill) the Fliiight just cant move the magnets close enough to get the right resistance on the rear wheel. You can set the tolerances lower but you can’t get them close enough to make it perfect.

In a nut shell if you want to get faster stop racing and playing on zwift and get on a structured training plan. Use ERG mode and beat all the zwift racers and players when it rely counts… On the open Road

The fliiiight is best suited for ERG mode. 99.9% of the population will never hit the watt ceiling using Big and small.

My 2 cents


Well I ordered a Fliiiight and I should have it around the of the week. After a few rides, I’ll post my thoughts here.


Got it last night - it shipped with firmware 3.7. I have the beta Android app and the the chrome os updater - both were able to talk to the trainer just fine.

There are minimal setup instructions in the box, but they are sufficient for a basic setup. To properly adjust it though you need to watch the YouTube videos from 4iiii and tweak it as they describe. All in all, an easy process.

At lower wheel speeds (small ring) it feels a little clunky. It is hard to maintain a smooth cadence. In the big ring though (52) and in the middle of the rear cassette and then to the smallest ring in the rear (11) it’s actually pretty smooth.

I didn’t do a full workout yet, I’m going to do some sweet spot tonight, but I did a bit of freeride and just a few minutes of taku to see how it felt and played with the app. I did not try zwift yet.

There is a lot of discussion about the trainer over on the comments section for dcrainmakers full review. It seems that that’s the place to go to get more specific advice.

It is very quiet. It highlights that I need to take better care of my own drive train!

I’ll do at least a sweet spot and some sort of more sprinty workout and I’ll update this thread with my impressions.


Any updates on how it went? Resurrecting this from a month ago. So thankful to have stumbled upon this thread (and just purchased a fliiiiiiight this evening). Arrives next week.

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Hi! At this point, I’m sure you’ve tried your 4iiii - but I’m happy to share my opinion. (I had meant to a while ago and forgot to do it.)

— Short version —

I like the trainer - if your use case requires quiet, this is a great value option - resistance mode is sometimes required to get back into erg mode - unclear info on latest firmware etc - android app stinks - works well enough in TR and zwift but sometimes does funky things that are hard to explain.

— Long version —

For the most part, I like the trainer. It is very quiet - if you have a noisy drivetrain, that’s what you will hear. I found it easy to setup and appreciated the videos 4iiii has on youtube. There are basically zero instructions in the box so you’ll need to go to the web for the setup videos.

I am not using the included usb c cable - I already had a 15 ft usb c cable so I’m using that instead. I need the extra length. The magnet feature of the included cable is cool, but it is tough to get the usb c head out after the fact, I had to use pliers to get it out when I decided I needed to use my long cable.

The leveling feet are great - really easy to get the thing level. The quality of the finish is good. The smart unit feels a touch plasticy to me - I think they could have used a nicer quality plastic or finished it a bit better. Not a big deal, but since the thing is made to be moved around, I don’t think that plastic would hold up to something metal crashing on it in the trunk of a car.

I like that it auto calibrates each time you turn it on.

On to use: In trainer road, in resistance mode, it works pretty smoothly. It doesn’t respond super fast to the computer, you get used to the delay, but it does respond and it does work well. Erg mode works fine too. I have no real experience with any other smart trainer but this works well enough. Again, the response is sometimes delayed by a few seconds. I haven’t tried a VO2 Max workout but sweet spot and tempo are fine. My suspicion is that it would have a hard time responding quickly to short and high wattage intervals.

There is no inertia feel at all - and its usability is entirely driven by wheel speed. Without a lot of speed on the rear wheel, you aren’t going to have a good training experience. I leave mine in the big ring (52) and I use the harder half of an 11-28 cassette. I spend a lot of time in 52-11.

If you have to pause while in erg mode you need to put the trainer into resistance mode at a low resistance (I do about 35%) and get that wheel speed back up before you go back to erg mode. I figured that out by trial and error and it was really frustrating until I got it.

I’ve used it in zwift a few times. I did a jon’s short mix once and it went really well until the middle of the 10 minute sweet spot block when the trainer just completely freaked out - resistance all over the place. Again, taking it out of erg, into resistance mode, and then back into erg solved it.

I’ve done a few rides on Tempus Fugit - that course is nearly totally flat - and the trainer works well there. You can feel it getting confused sometimes, like it will get harder when you are drafting, which shouldn’t happen, but for the most part that’s fine. I am going to try switching to the tri-bike in zwift to see if that addresses that issue.

If you want a quiet trainer that you can move around your house without having annoying calibration issues, this is a good trainer. If you want a really good trainer that gives you a great training experience, this is not your trainer.

The trainer is sort of like rollers - I have a set of tacx rollers and I have the feedback sports omnium trainer and this is not so different from those. The lack of inertia is what makes it feel similar. I also have an old tacx satori (dumb - not smart model). The road feel on the satori is much better. I’ve previously owned a lemond revolution which felt great but was way way too loud for my NYC apartment.

I want to be clear - I don’t expect it to have inertia - there is no flywheel after all! Its just that an old, used trainer, generally feels better to me.

I am an android user and the android app stinks. I have also used the chrome web app which is also not intutitive or helpful. Plus, I can’t figure out where to look to see what the latest firmware is, etc, other than by reading the thread on DC rainmaker where it appears there is some STAC/4iiii support. I wish 4iiii would provide some sort of easier to access documentation.

For my money, unless you need it to be real quiet because you have a cranky downstairs neighbor and you’d like to be able to train in the mornings, most people would probably be happier with something like a kurt kinetic and a crank based power meter. You’d get reliable data, have better road feel, and not have to deal with the unit making strange resistance decisions!

Thought I’d add a bit - I’ve got a few more workouts done.

In zwift, it does better when you are on the tri-bike. It removes the layer of figuring out resistance change when drafting. It does better on flat terrain with small changes in elevation. I tried it in Titan’s Grove and it did ok, some of it is me just not being used to needing to shift, some of it was the trainer being a bit choppy with its responsiveness. I’m going to put on a narrower range cassette to see if that helps me.

I did Acho today in TR and it went pretty well. Other than one blip when it got too easy for about 2 seconds in the middle of an interval, there were no issues. I should mention that I also have a 4iiii podium powermeter on my left crank and that I’m using the powermatch option. Also, I’m connecting via ant+.

Last comment unless anyone asks questions later -

I just did a ramp test and I had a hard time getting the power to go above about 250 watts in the test. I had to spin my legs at about 100 to 110 to get to 250, 260 watts.

That doesn’t seem to make sense to me as I know that I can put out a lot more power, on the 4iiii trainer, in either zwift or in TR. So I’m not sure whether the issue is with how the trainer talks to TR or is it a 4iiii specific issue or whatever. My ftp is 220 with the 4iiii pm and on the tacx satori.