Hi Everyone
Apologies if this question has been answered previously or if there is already an answer to this question somewhere that I’ve not found, but I’ve only recently started using Zwift. I’m using a dumb trainer with a Garmin 2 speed sensor and cadence sensor.
I’ve noticed that when I get to sprint sections I seem to top out at 7.4w/kg and can’t get past 374kw output. Is there a reason for this? Would buying a smart trainer resolve this?
Certain trainers are limited but normally it’s 400 w. You’ll know it’s limiting you if you sprint and the power line goes up and then horizontal for as long as you sprint. Or you sprint and look at the power number and it stays the same for several seconds. Have you seen this behaviour or do you sprint and it peaks for a second and then comes back down ?
It’s hard to tell as I’m usually trying to sprint! 
- From what I can tell I can be sprinting and it hits 7.4w/kg and if I push harder it just caps at 7.4w/kg (even when I have more in the tank and put in extra power). Meanwhile, I can see others topping over 10w/kg and above. It doesn’t matter how hard I push it just seems to hit a ceiling at 374w and won’t go any higher than that regardless of how hard I peddle.
Press G in game to see the graph. Leave the graph on. Sprint. See if it spikes, or if it goes flat.
How competitive are you in real life cycling?
If it goes flat a better trainer will allow zwift to read higher max power.
Yes Gavin. I learned yesterday that ‘unlisted’ turbos are capped at 400W, so you’re (I’m) wasting effort sprinting 
You can upload your .fit file to Strava and look at your numbers there. On classic trainers your power is derived from wheel speed, so it can be that your gears a limiting you. Look at your cadence and see if you increase it if your power goes up.
Are you already in the hardest gear and spinning out? Remember that there is no power measured with your set up so hitting very high speeds is what will determine the power calculation.