Zwift vs. real life - tested


according to my results in Zwift (and my races on zwiftpower), my FTP is 5 w/kg. I have done several races on Zwift, I’m in A class (even A+).

I recently did an amateur race on a road bike in real life. It took me 60 minutes to do 11.5 km and 800 meters of elevation gain. Very high heart rate (average: 175 bpm).

Why the difference between my results on Zwift and my results in real life? I am using a TUNTURI E50. Faulty wattmeter on my indoor bike? Position on road bike less favorable than indoor bike?

Thank you for your answers.

It could very well be that your power meter is not calibrated properly. Can you please share a link to the power meter you are using? I am not familiar with that brand. If it is using Zpower, your indoor stats are likely not accurate.

Your are riding an exercise bike. It’s completely different to riding a road bike in real life.

Different position, different resistance.

To try and compare your stats on that compared to real life is about as inaccurate as you’ll ever get.

Maybe a local bike shop or coach could help you do a power test with your road bike on a known good direct-drive trainer, one of the popular ones that you race against.

I understand that in real life the values are not the same as in the indoor . However, with the same parameters (bike weight, slope, length, elevation gain) the total effort and travel time should be at least similar.

If this is not the case, it means that the watts generated by my exercise bicycle are not correct at all. I can imagine a margin of error of 10 or 15%, but no more than that.

What do you think?

Is it possible that a different position in the bike makes that much difference?

What are you using for a power meter?

A 10-15% margin of error is huge. At 300 watts that 330 or 345. Huge difference.

Most direct drive trainers are now about 99% accurate.

How long does it take you to do 11.5 km and 800 meters of elevation gain in Zwift? That sounds like a decently stiff climb. How did you do in the race?

I’m a slow B on Zwift and I raced in a category 5 criterium irl a few weeks ago. Got my legs ripped off :joy:, dropped at 13 minutes (race was 40 minutes). Got 12th place out of 22 so could’ve been worse.

At speeds like that, riding position has practically zero effect on the power needed (but of course it can impact the power you can produce because of biomechanics). Exercise bikes generally deliver notoriously unreliable power numbers so I’d start looking there.

Tunturi E50, it is an exercice bike (ergometer).

I’m no expert but my guess is your Tunturi is not calibrated correctly.
Compare your IRL ride with your Alpe Du Zwift rides (approx 1000m and 12km) which you have done in around 46 minutes.
Not sure ride position, CDA, rolling resistance, or any other metric really has much bearing on the difference.
(I’m assuming IRL you are not doing hill climb on racing trike or penny farthing)

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You’re apparently at 350W.


When I started training with this excercice bike I had an FTP of 200 watts, completely in line with my (real) mountain biking hobby.

Today, if you can produce 350 watts for an hour…your FTP is 350! Unless the wattmeter is completely faulty.

One of two things: either my wattmeter is totally faulty, or there is a major difference in the ride/position/other factors of the real racing bike.

I’d work under the assumption that thing is completely unreliable. However, even when it’s not: max watt with thah thing is 350 watts. If your FTP is indeed 350 watt you would want a trainer that can handle more power. Get a ‘normal’ one of which some suggestions have been made. You can only win: Get a reliable number or you can train to bring it beyond your FTP of 350.

all of the above


It would be possible that your body weight is incorrect, for example if the setting is in pounds but you provided your weight in kg, that would double the w/kg

At 5 w/kg that 11.6km 800m ride should take you less than 40 minutes. You’re probably closer to 3 w/kg at that pace, maybe even less. I regularly do this climb around 3 w/kg in less than an hour:

Looks like your exercise bike is a pos overestimating your power by 70%. Get something else if you want to train accurately.