Support Indoor Bike: Schwinn IC4 - Bowflex C6 - Schwinn IC8 (Europe)

Zwift engineers please “support” the indoor bike: Schwinn IC4 - Bowflex C6 - Schwinn IC8 (European Version). They are all the same bike under different marketing names. Nautilus (the parent company) is advertising that they are compatible with Zwift on their websites, but the watt readings are way too high. (See the many posts on this on your forums.) Either the power curve is wrong on the bike console or the power curve is wrong in Zwift.

Nautilus should not advertise that it is compatible with Zwift. Power meter pedals are required to make the bike accurate enough for use. Many cycling novices are buying the bike(s) having no idea what their FTP is and not suspecting that they are cheating until they get a few weeks into it.

The bike also BLE links as “controllable” by default and it is not. At minimum please reach out to Nautilus to remove advertising that it works with Zwift until they comply with your protocols for accuracy.

If the bike pair as a power source then Zwift don’t use a power curve, zwift will display the power data that the bike send to zwift.

What power numbers do you see if you pair a cycling computer (like garmin) does that match what you see on the bike console and does that match to what you see on zwift.

It does pair as a power source.

I don’t have any software that I’ve used to date. I do not have a Garmin computer. What do you recommend? Is there a free app that would understand the same BLE language from that Zwift does?

I am sure there must be some phone apps that will act like a cycling computer. I have not searched, yet.

Found one called trainer road which should give me something to compare Watt readings to.

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I could not find a free open source BLE power meter logging app. Trainer Road was not free for receiving power data.

FulGaz however links via BLE to the bike console and was also showing high power readings. So it’s Schwinn’s/Nautilus’ console that does not have a correct power curve for calculating the watts it is reporting. It registers as “IC Bike” on Zwift and FulGaz. Zwift might want to flag those equipment registrations if possible app side and require a cadence only connection until the Schwinn fixes it’s power curve or at least warn users.

Also, it is reporting as “controllable,” which it is not. I’m not sure which side of the programming would be to blame for that.

Is there anywhere to go from here?

Any known plans to “support” Schwinn IC4 or IC8 / Bowflex C6? I’m considering a return based off of false advertising that it works with Zwift and other apps. It does technically… but the data is way off and there is no way to “calibrate” it. FYI, I have called and spoken to tech support and they sent out a new console to fix the issue but there was no change.

Zwifter: Andy King (aka Andy Kingster) had the same experience.

Yes, you can just “click” controllable to manually disconnect it. It just seems it should not connect by default when it is not controllable. (This is really a small side issue to the watts not being reported accurately though.)

I have not tried zwifting with cadence only connected. I think it just guesses your probable power and maxes the power output at 400w.

I purchased the Schwinn IC4 in mid December and was enjoying it thoroughly. I’ve done some races and placed well which was great since I’m an athletic and competitive guy. But as my technique and cycling fitness grew I started doing suspiciously well.

I decided to do a ride up the Alpe du Zwift on Tuesday evening but instead of going at it at a reasonable pace I wanted to see how long I could last out of the saddle with the resistance cranked to 100 and pedalling at a low cadence. Shortly after beginning I was flagged with a flier warning (cone of shame). After doing some googling to see what that even was I find myself here, disappointed that a machine I forked over considerable money for is inflating my numbers.

Looking at my data it appears I was averaging 550W or roughly 7.1 w/kg for the 43 mins it took me to get up the mountain. I’m not well versed in what realistic numbers are but from what I googled I don’t think mine were attainable for a non professional. I was trying hard but I don’t think my results are right.

I’m super bummed if that’s the case. I like to win but I don’t want to if all my numbers are off. It’s not fair to my fitness goals or the other people I’m racing against.

Does your Scwinn come with instructions on how to “zero” it’s built-in power meter? I have and have found the M-counsel I power meter to be pretty close to reality once I got it set up correctly. I you are actually turning out a sustained 550 watts you should be trying out for the Tour de France. Keep on peddling. :+1::sunglasses:

Ok I have an update. I did the calibration process that was posted here. So it appears my max resistance setting was too low. I could still turn the knob 1 or 2 times after the console read 100 resistance when it says you should only be able to give it a quarter turn.

So now if I repeat my resistance setting and cadence from before I still get the same wattage output but it is more difficult of an effort to do so. How does it compare to other power meters I can’t tell you. But it is more difficult which is a start.

Can I still do that up the Alpe du Zwift? I don’t know. I really didn’t feel like punishing myself like that today. I’ll have to build up the willpower to try again another time.

A final note for others with the Schwinn IC4 (probably the other models too) when you are doing the calibration for the max resistance it says to turn the knob all the way and then back a quarter turn. But this gave me a rubbing noise when at a 100. So I did it again but I stopped at the point where the rubbing noise began and then went back a quarter turn from there. Now my 100 resistance setting is noise free. Also be careful because it says you can only recalibrate a total of 3 times.

I hope this helps. And if anyone has comparison numbers between a properly calibrated schwinn and other power meters I’d love to see them.


Stephen, I’ve done a little bit of comparison with the IC4, a Wahoo Kickr Core, and some Favero Assioma power pedals. I was fortunate to have been using the Kickr Core before I got the IC4, therefore I knew the output was way off on the IC4. In fact, the first ride I did with the IC4 I joined one of the Tour de Zwift group rides, I started a little late and started in 400+ place. In about 8 minutes I had climbed past all 400+ riders into first place without hardly breaking a sweat! Also had noticed one of the time trials on that ride I must have done earlier on the Kickr Core I had done in 17 minutes, this ride I did it in 7 minutes. A comparison I did early on after getting the bike was the FTP ramp test. One day I got 183 with the Kickr Core, the next day I did it with the power meter pedals and got exactly the same. 10 minutes later (so probably not fully recovered yet) I did it with the IC4 and got 390. So in my experience the IC4 is outputting at least (and probably a little more than) 2x higher than what it should be. At first, talking with Schwinn support they made it sound like it was Zwifts problem. The last time I talked to them (a couple days ago) they said the R&D team was working on a firmware upgrade to fix the issue. Sounds like you cannot upgrade the firmware on the existing display, so will need to be replaced with a new unit once available. I asked him to please send me an email notification once they have new displays with updated firmware available. For now, I’m using the bike with the power pedals which works great.

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Did you end up trying the calibration steps for the IC4?

No, I did look into it but didn’t like the fact that it says you can only calibrate 3 times. I think it also said it fixes problems such as resistance being stuck on zero or doesn’t go all the way to 100 or all the way down to 0, mine seems to smoothly go from 1-100 so I don’t feel theres any issues with the calibration. The past couple calls i’ve had with Schwinn support, they have said they have gotten many calls on this issue and are working on a solution to make it compatible with Zwift so hoping they have a fix soon. I did another test having the bike connected to Zwift and my power meter pedals connected to the Kinetic app. Started recording at the same time and just rode for about 10 minutes at different speeds and resistances. When done I had an average wattage of 339 on the bike and 149 on the pedals. Which is close to the same difference I had doing the FTP tests, so seems actual watts is about 45% of what the bike is showing on Zwift.


Thanks for testing this so thoroughly David. Seems like new pedals is the only option…

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Does anyone have the instructions on how to calibrate the resistance knob/levels for the IC4? Mine has to be way off.

Run this speed calibration check first.

If the speed is off, then run the calibration procedure found here.

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thanks. My speed check seemed pretty close at what you provided. I also did a recalibration (thanks!), and speeds are good to the chart you posted. I still think its showing way too high 37mph+ when I have higher resistance. That seems crazy to me (I could hardly get near 30mph at my gym).

I’ve only been able to go that fast on a big downhill, no way you are going that speed on a flat road in real life.

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Thanks for this. I did it and seems much much better. Like you, if I turned clockwise for the 100 setting all the way, it was ridiculous. I just pedaled until it took me standing up and extreme effort and made that the 100 mark. Did you do the same? From what Pelaton guys say, 100 is still “doable” on those bikes it’s just very hard. On the IC4 that seems to be about 1 turn from all the way.

If I crank it to 100 I’m always out of the saddle either with a low cadence going up a hill or givin’ er hard on a sprint.

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