Hi all,
As stated in the title, I started on Zwift yesterday, and already did some runs and FTP tests.
And after all these, as I’m weighting 55kg, I found that my FTP is around 105-110W (2w/kg), my max power up to 510W (9.3w/kg), and my cruising power at 55W (1w/kg).
So is one of these stats higher than what it should be considering the others ?
Thx for your help already 
There’s really no way anyone can give you a meaningful answer to your question. Assuming your trainer is properly set-up and calibrated, the numbers are what they are.
Your max power isn’t impossibly high for someone your size, if that’s what you’re asking.
In short, it depends. People are different.
Read “Power Profiling,” by Dr. Andrew Coggan, Ph.D. Here’s an extract:
“It is simply human nature to wonder how one compares with others for any measurement … such category-based values would seem to have limited practical use… If, however, valid standards were available for power across different durations that represented different physiological characteristics or abilities, then it would be possible to identify a particular individual’s relative strengths and weaknesses based on their ‘power profile.’ In such an analysis, the primary comparison would therefore be the rider against themselves, and not (directly) against others. Such information could be then used to help plan an individualized training program, evaluate the effectiveness thereof, and to possibly identify events where an individual might be expected to achieve the greatest success.”
What’s your setup? 55 watts as a cruising power is really low. For me that’s pretty much spinning the cranks with zero resistance.
I use the Qubo Digital Smart B+, and for the bike, it’s an old Lapierre from the 80’s according to my research, but the chain is only 3 years old, and the tire is brand new.
And actually I just bought a scale, so I’m not weighting 55kg as it was years ago, but 51 instead. Even if it’s not the same scale, imo it should be precised.
I compared my Zwift datas with the cruises I did last summer, and on Zwift all of them are around 30% lower than my IRL results.
In Zwift, delivering 55w leads me up to 25km/h on flat, which is my IRL cruise speed, but there, according to a calculator I googled, I need to deliver around 77w (1.4 higher than on Zwift) ! And that I can do for several hours
Tip - Don’t ride up Alpe du Zwift (requires you to be level 12) as cruising at 55 watts it’s going to take a long time to reach the top!!
If you know anyone else on Zwift you should try and ride their setup as your power accuracy could be way off.
According to your profile, you are 5’ 11” - and you say you only weigh 51 kg?!? 
Yep,
Whatever I eat, I stay at this kind of weight. Sometimes it’s useful, but sometimes I wish I would have weighted 65kg at least … ^^’
Unfortunatly I don’t know anyone cycling 
And don’t worry for the Alpe, when I will unlock it, I would do it faster than that, as I will climb out of the saddle 
and also deliver more power than that, my 55w cruise is on the flat, didn’t check how much it was on climbing.
EDIT I just did the Mountain Route, and I deliver around 2-2.5w/kg in climbing