When using the “select power source” screen in Zwift I can see directly how my re-calibrated bike compares to the power meter pedals, as it shows wattage from both sources at the same time. Similar to you- I notice that Nautilus output matches up pretty closely with the power meter at mid-range levels, but then starts to get inflated at higher levels.
I think we’ve probably reached the limits of what can be achieved with the hard-coded Nautilus power output algorithm. I suspect that any more tinkering to get my higher resistance levels in line would throw my lower and mid range levels off. Plus, like you say, we’re limited to three kicks at the can for calibration, and I’ve already used two!
Hi! I have read through the whole list, and there is so much information. What is the conclusion here… have they fixed the problem if I buy an IC8 bike and want to do Zwift, or do I need to calibrate, and I will get some various results?
No news. I followed up with Nautilus recently and they said that they have made no progress on fixing the issue, and don’t expect to have a resolution anytime soon. My only advice at this point is that if you buy the Schwinn/Bowflex bike to use with Zwift and you want accuracy or plan to race, you should budget for a pedal-based power meter.
Then you might as well buy a used spin bike for $100.00 and save the money for power pedals. No need for a “smart” spin bike that you don’t use the features. In my opinion that’s the best way to do it.
I can’t speak to the quality of what you might get for a $100 used spin bike, but I would point out that apart from the Zwift compatibility issues, I’ve been very impressed with the Nautilus bike’s overall quality. Our whole family uses it and we find it has enough adjustable components that it can fit everyone very comfortably. I think most important is that it feels close to a real bike when we’re pedaling on it. That is what makes the Zwift experience enjoyable. So whether you get this bike, or look for a cheaper alternative, make sure it feels like you are seated on something resembling a real bike when you test it out.
Not intending to be an AH but… How can this help anyone to see if the bike is giving correct outputs?
Every bike has its own random power calibration, depending on that it can be reading 250w@R25@90RPM, and the real value be 175w@R25@90RPM or 300w@R25@90RPM, for example mines is reading 200W@R25@80RPM and for your chart is 10% off, and I would think, good enough. But when my assiomas are in charge of reading R25@90RPM the real output are only 130W, so almost 50 percent off.
Although your chart is irrelevant for assessing if their bikes are showing correct input, it can help people decide if the bike has enough resistance for their intend and it surely helped me decide in buying this bike, so thanks!
After some more tests, with power meter / resistances / power from bike, some conclusions:
The range of disparity goes from 5 to 60 percent and it was impossible to calibrate the bike correctly (no more tries for me ):
R20@100RPM
Assioma Power - 150w
IC8 Power- 235W
R30@90RPM
Assioma Power - 230w
IC8 Power - 255w
R40@90RPM
Assioma Power - 320w
IC8 Power - 335w
Conclusion 0: The resistance given by console (R20/R30 etc) is not always the same real resistance. Tests in morning and at afternoon were showing 10-15 percent difference at same resistance in the power read by the pedals.
Conclusion 1: The bike is impossible to calibrate with the power algorithm / hardware it has.
Conclusion 2: It is impossible to measure accurattely our improvement, unless we always use the same resistance and cadence, and even so I’m not sure because the same level of resistance doesnt show same power. (e.g R20 in the morning ar 90 rpm 130, in the afternoon 150)
Last conclusion:
I had a 300€ pad bike that died, and this bike has a much better riding feeling, pedal stroke is cool and smooth, but if I didn’t already have the assioma unos power meter and a wife that I need to share the bike with I would have bought for the same price a cheap road bike (300€) and a Kickr Core (800€)
Hi Bruno. The chart uses the Assiomas as the accurate power reading and shows a range of outputs across resistance levels. If someone has calibrated their bike following the instructions I set out, and receives the same power output numbers on their bike (vs. my pedals) at the various resistance/RPM levels levels I plotted, it would show that it’s possible to get accurate, consistent power output using the bike’s output. The chart wouldn’t be helpful if you’re only referencing it at one plot point. You would want to check across the various ranges for discrepancies. However, your point about getting different power readings at the same resistance in the morning and afternoon is news. I did not get that with my bike, although I agree that could everything off.
Good luck on your emotional journey with this issue. I think like most people here, you’ll find that the pedals give you the peace of mind to stop worrying about power accuracy. The only question left is whether the “feel” of the Nautilus bike is worth the price tag. The jury is still out for me on that one!
Having read all 300+ posts in this topic, as a new 800IC owner (this is the new name of the IC8) I can say from my short experience with the bike that I love riding it, and that I’m getting fairly comparable watts at the resistance level/rpm combinations that someone previously posted using Assioma pedals. Surely, I didn’t expect to get 230 FTP as a novice rider (with a decent physical condition otherwise), but at least it isn’t something as crazy as 360 that some of the previous posters have mentioned. So I guess the “fix” has been implemented on new units (which are now dubbed 800IC in stead of IC8)? Or maybe mine is just calibrated better than the ones others have received? I’m not sure, but I have no reason I can think of as to why I a shouldn’t be allowed to participate in (friendly) races in good conscience. I’m interested to hear if others who have recently bought it are experiencing more realistic values out-of-the-box just like I do.
If I’m getting similar wattages on certain resistance levels, with the same RPM, as the person who tested it with power pedals, than surely it is reliable (with a certain margin of error). Apparently my bike is calibrated in such a way that for each resistance*RPM, my wattage output is very close to what my output would be on his power pedals.
I think if she has a calibrated bike and is consistently getting the same wattage as my pedals, at matching resistance x RPM, that is a sign of accuracy, is it not? Isn’t Bruno’s main problem that he was getting different output at different times of the day, despite all other variables being the same?
Yeah exactly. I tested it twice now, once in the morning on a rainy day, and yesterday when it was hot in the afternoon. Got similar wattages for Resistance*RPM levels as the previous test, so it not only seems accurate (compared to pedals) but also reliable (based on these two tests). I guess the latest version (now dubbed 800IC in stead of IC8) has the fix they have been talking about for a long time? Or maybe I’m just lucky… Did anyone else test the 800IC yet?
I’m a new Ic8 owner. I had my first Zwift ride two days ago and the results were… unbelievable.
26km in 45 Minutes in Yorksire. (no way)
Average Speed 34,7km/h max 89,6km/h (noooooo waaaaay!!!)
Average Cadence 87 max 115 (real)
Average Power 311 with max power 598 (noooooo waaaaay!!!)
135 Average heart rate, 160 max (real)
I’m 46 years old in good fit (still overweight) as I’m a runner for years, but I’m moving to bicycle after a bad ankle injury. As a real measure, I did a 20km real road route on an mtb a few days ago with some hills (less elevation than Yorksire) at 22km/h average. No way I can have an average of 34.7kmh and no way I can reach almost 90kmh even falling from an airplane. I had never measure my power before but I can’t believe I can sustain 311, probably is more close to 200 or even lower.
I guess I need to calibrate my bike. The resistance knob seems to be ok, all to the left is at 0 and at 100 I can’t move it. But below 20-30 I don’t feel a comparable resistance to riding in a real bike. I had most of my Ziwft ride at around 40 resistance (tested 80 for a hill, I guess that is the max wattage I archived), that was tiresome for 45 minutes but bearable. Is it normal to have no resistance at all at 0 and to need to use 20 to feel that at least you are riding a real bike?
Regarding the app, I was the top rider in most of the segments and I was passing all the other riders like if I was on a motorbike, with my avatar in sprinting position all the time that looked ridiculous.
I must say the experience was not what I was expecting even after reading the forums about over reporting, to the point I’m considering my Zwift subscription if this is what I will get. I’m not going to compete in virtual races and I know I can ignore the exaggerated measures and just take them as the starting point to improve from but… felt really stupid and also when the ride was exported to Strava with 15 new Prs and that extreme measures, I felt embarrassed.
Besides trying to calibrate the bike, that will do today and will report the results, can I do anything in Zwift to compensate? like set a small wheel diameter so my speed is lower? or to raise/lower my real weight/height? I wonder if Zwift could implemente an easy fix for us so we can tell it to just divide by 2 whatever measure you get from my bike. As long as you can only reduce your bike output, that feature it couldn’t be used to cheat and can make us happy.
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