Problem: big difference between Zwift and reality

Hi all,

Yesterday was my first day with Zwift and I rode like a rocket. There is a big difference between the speed of my Fit Bike race 4 and my speed in Zwift. In Zwift I ride almost twice as fast as in reality.

Anyone knows what to do to get a more realistic experience?

You’ll need to provide information on your setup for anyone to be able to help.

Are they both set to show kilometers or miles?
Did the distance match?

Before I start responding with the wrong information: which information of the setup do you need?

I think the difference is caused by miles and kilometers, allthough they are both set in kilometers as far as I can see.

Typically your trainer, the device you’re using to run Zwift, and how you’re making the connection between the two.

Good morning @Marcel_Stok

I assume you are using this bike:

Does the spinning bike transmit power?

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The speed your exercise bike shows is based purely on the flywheel speed whereas zwift takes into account the terrain you’re riding on, going uphill is slower and downhill is faster.

the two speed will never match.
if you ride your bike outside and keep your cadence the same and don’t change gear you’ll go slower uphills and faster downhills. this is what zwift is doing in game.

It appears that the FitBike Race 4 has no electronics and a very light flywheel which may contribute to excessive flywheel speed and variability. However the bike appears to have 9/16" pedals so buying a pedal based power meter and cycling shoes is probably the best solution for Zwift.

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I think buying a secondhand bike and second hand tacx flow would be a better zwifting experience and likely cheaper

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Hi @Marcel_Stok,

I am having the same Indoor Cycle (Fitbike Race 4) and experiencing the same behavior of a much higher kph speed in Zwift compared to the kph speed on my bike’s display (which I believe is pretty accurate).

Did you ever manage to solve this?


If you ride outside, in the same gear and cadence, you will go the same speed on the flats and uphills. Downhill would be a crapshoot, depending on the grade.

true - my bad - i think i meant if you keep your power the same. past me was young and foolish

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Old post, but as I’ve got the same bike, thought I’d chime in:

TBH I’ve found the effort-to-speed quite realistic. I have an outdoor (ebike) with a watt meter (that displays my own contribution) and I know what 100 watts feels like, and I know that on a lighter bike with a decent drive train, with a more aero setup I’d be getting circa 25 kmph on the flat, no problem.

When the zwift app reports that I’m giving about 100 W, it feels about the same as what I get on my ebike.

I think, rather than the “speed” that’s reported on the fitbike computer, look at the calories it reports you’ve used in, say, 30 minutes, for example.

Google for “inchcalculator calorie to watt hour converter”

Note, that the fitbike reports in kcal, so x1000 whatever it reports and input that into the converter. See how many watt hours it gives you.

I put in 40,000 for my half hour ride, (the fitbike computer told me 40) and the converter told me that was 46.5 Watt hours, which is equivalent to a continuous output of 93 Watts for half an hour, which is roughly what I had reported in the zwift app for the ride.

So it’s probably + / - 10%, but for a $400 setup I’m not going to complain. And I’m certainly not going to drop another $300 on pedal sensors.

Maybe they updated the firmware or something, or maybe the build tolerances are so loose that there’s a tonne of variation between bikes, but my experience with it has been fairly OK so far.

It’s OK as long as you don’t race.

At what resistence (how many times have you turned) have you put the Race 4

I think it’s about 2 full turns to the + (from the lowest resistance), and with a cadence of around 90 rpm I’m getting about 100 (probably a little over) watts. On the lowest resistance I need about 100-110 rpm to get about 110 watts.

I think the fundamental truth is that there is pretty much zero credibility to your “in-game” performance with your current setup…but depending on what you are using Zwift for, that may or may not be of any concern to you.