I have an Horizon3.0sc exercise bike. The feedback from the community is the figures the bike is feeding Zwift are inaccurate… watts and resultant zFTP is far higher than I am capable of producing.
Whilst I’d like to think I’m awesome the reality is in the back of my mind I tend to agree with them. So how do I validate the figures… the bikes algorithms are auto loaded and Zwift doesnt give the option to calibrate power sensors… I’ve checked numerous videos and pdfs and the spanner option doesnt appear for my bike.
I’ve emailed Johnson Fitness and am awaiting response… as regards accuracy of figures… some things that effect accuracy is bike only has 32 levels and goung by Zwift the bike cannot simulate elevation higher the 7.5% or watts above 999W… so do I change the bile and take the loss of £799 or is there a way to correctly calibrate and give correct input to zwift.?
The manufacturer can say for certain about calibration options, but almost no spin bikes support calibration, nor do they make any verifiable accuracy claims. They’re just a fun toy that makes riding indoors less boring but they can’t be used to understand your power. Zwift can’t calibrate a trainer that has no calibration capability.
The best way to validate the trainer’s power measurement would be to add a set of power meter pedals and record power from both the bike and the pedals on the same ride. Power meter pedals may cost more than the bike. Borrowing power meter pedals is a good option if you know someone or are part of a local bike club where you can ask around. If you get hold of some power meter pedals you can get more advice here about how to do the dual recording.
Other ways to validate it, which would still be useful, would be to do a ride on some other well known trainer and see if you can replicate the numbers you are seeing. So again you could ask friends or a local club if anyone has a trainer you can borrow, assuming you have a bicycle to install on it. A high quality smart bike like a Wahoo Kickr Bike, Tacx Neo Bike, or Wattbike Atom/Proton model would also be OK. Other random spin bikes that don’t promise any level of accuracy would not be a good test.
It’s tough to know what options you have because I can’t find good documentation for the bike. I found a PDF tech manual, but it turned out to be a manual for a cybersecurity platform called Horizon3, lol. If the bike has regular pedals, you could put some power meter pedals on (as Paul is saying, I am seeing pop up above just now). But some spin bikes have proprietary pedal/threads.
There’s no way to ‘dial down’ a trainer’s reported output though. So even if you rode on something else for a bit to see what your own personal error is from this bike, there’d be no way of adjusting this bike when using it on Zwift.
Cheapest options (I’m very sympathetic to cycling costing way more money than it should):
A) Check if the pedals are standard pedals, and if so, see if you can find a second-hand set of power meter pedals, and swap out the stock ones.
B) Second-hand bike (doesn’t need to be spectacular) and one of the cheaper smart trainers (Jet Black Volt, Kickr Core).
C) Either of those options, but new pedals/bike.
That is something the QZ app can do (qzfitness.com). There’s no guarantee that an inaccurate bike is equally inaccurate across all levels of effort you put out, so results may be strange but it can be done.
Personally, since I have some interest in knowing my power, if I had that bike I would sell it to someone who doesn’t care about accurate power and replace it with a mainstream smart trainer. Being a recreational athlete I don’t have super high standards for accuracy but it has to be better than that bike.
Most spin bikes do not have power readings, but ESTIMATE power based on mechanical positioning of brake calliper etc.
They can not and will never be accurate, but some can be adjusted to have a closer to real life values.
The few spin bikes that actually have power READINGS, cost the same and more as a kickr bike…….often without the accuracy
Thanks for sharing your experience much appreciated. I’m hovering on changing the bike… even though its a great bike mechanically speaking… the metrics are/have become an importat part of my riding through Zwift and Trainer Road…
One of the reasonns I picked this bike was its footprint being small… looking at the options Kickr shift would be my dream pick but space is a factor so Wattbike Proton could probably be the best option… as I was planning to go for a bike with gear simulatikn and better elevation simulation… as the Horizon, has only 32 resistance levels and from what I can work out… cant simulate above + or - 7.5% gradient.
Option B not viable as footprint for that type of set up too long and I have nowhere to leave it set up… shame as Zwift bike looks good value.
So as I said thanks for response appreciated: )
Considering selling and going for Wattbike Proton due to it having small footprinnt but significant upgrade in virtual gears and higher power level capability of 1600W which should be ok for now 
aswell as better adjustment and has reviewed well from the many reports I’ve read.
“However, Wattbike says that the Proton isn’t directly aimed at the serious Zwift racer, instead they recommend the Wattbike ATOM series for the best experience there.”
So there are pitfalls whichever way you go, but if price is a challenge there is a strong second hand wattbike community.
You can get a used version for 800-1200 depending upon usage and model of Atom. A service is now £300 to get it running like factory new.
Wattbike are currently discounting new bikes.
The one challenge is Wattbike is currently experiencing funding challenges.
Wattbikes can also fall very much out of kilter and these can’t be calibrated without returning them to Wattbike in Nottingham. Regardless it will be a whole lot more accurate than the spin bike.
That would be a huge improvement. FYI the Proton model does not get the in-game gear display on Zwift, but the Atom does. I don’t think there’s any reason it can’t, but it hasn’t been implemented yet.
If you do buy a better trainer, you can contact Zwift support and ask them to reset your historical power numbers so you can race in an appropriate category.
What is the obstacle to someone making a indoor cycling trainer for a lot less money? Take for example the Horizon 5.0. It sells in the US for $599.
OTOH, you have trainers that include some sort of accurate power meter reporting such as a JetBlack Victory that sells for $400. So, presuming the power meter portion of something like this is $200. Why is it that to get an all-in-one cycling trainer with a real power meter in it, the price jumps to $2k+ ?
Looking at your current setup it should fit, maybe you’d need to move the plant a bit…
And get some sort of trainer mat to put under the bike - your carpet will thank you later for not becoming soaked with sweat.
Because that’s what the market will pay for it. If they did what you suggest then they’d have to sell a lot more volume to make the same profits, which is a big risk.
If Horizon stuck a $2-300 power meter in their $600 stationary bike, and instead sold it for around $1k, they’d basically be the only manufacturer with such a thing on the market.
Until the many other manufacturers copied them, you mean?
Edit - there’s also the issue about the market for such bikes. Manufacturers likely see a much bigger market for inaccurate $600 exercise bikes than for more accurate $1000 exercise bikes. A large proportion of buyers in this market probably have not understanding of or interest in accurate power figures.
I agree–something like the Zwift Ride + Trainer should fit in roughly that space. Or a trainer plus real bike, but take off the front wheel and put something under the fork. That fan could be moved up onto the window seat and still be mostly in front.
Hey, I have modded a few pieces of fitness equipment to make them compatible with Zwift (“frankentrainers”). If you are up for a bit of hacking, I might be able to help you get your bike to report reasonably accurate power. I’d probably still recommend against “seriously” racing it though.
Most of these bikes use resistance straps (less good) or magnetic eddy-braking (better) to provide the resistance. They then measure cadence and your power output is the usual force over distance over time calculation. The problem, as others have mentioined, is that there is typically no actual force sensor in the system. It is done by dead reckoning from factory build specifications so tension for the strap units or the distance of the magnets from the flywheel for eddy braking units has to be set exactly the same at the factory for it to be even slightly accurate. Spoiler alert: this does not seem to happen in many cases.
If I were going to address this, I’d use a power remapping app as others have mentioned. Or, since I like taking things apart, I’d see if there is a way to adjust the resistance. For a strap unit that would involve slightly tightening the straps so you feel more tension. For a magnetic unit, you’d want to move the magnet carrier or adjuster closer to the flywheel to increase the eddy current resistance.
If the unit happens to have active coils for supplying resistance, there is probably no easy way to adjust it, although I would be very surprised to see this kind of resistance control in a trainer like this.
As far as calibration goes, you’d need some power pedals to do it right, but I’d just start by cranking up the resistance until it seems to match the wattage you should actually be doing. I know, easier said than done.
Or… get a $100 mountain bike and a $300 used Wahoo Kickr Core off FB Marketplace and call it a day 
Best of luck either way. And please don’t let this discourage you from your fitness journey! If nothing else, keep riding what you have but maybe don’t join the “serious” races. I can let you in on a little secret. The technical term for any Zwift event that does not have banding or a hard fence is “A Race”. You can always join some of those although folks in the ride will probably call you names. Heh.
J
Which you’ll never know if you turn off chat.
Pro Tip.