Zwift and watt bike giving different readings

Evening all, I’m a newbie to Zwift so go easy on me! :grin: I did a trial session today on a watt bike however the distance and speed between the 2 were massive. The Watt Bike was giving the more accurate speed and distance where as Zwift was quite a way out. has anyone else experienced similar problems? Thanks

Ok, the speed and distance of the WattBike and Zwift will hardly ever match.

This is how Zwift speed is determined:

Watts broadcast, the weight entered, height entered, in-game bike used, in-game drafting (Tri and TT bikes get no drafting boost), in-game wheel set, in-game road surface, and in-game virtual elevation changes your in-game speed is determined.

Your WattBike does not know about most of these variables.

I really should make this a sticky somewhere:


Thanks for your reply Paul.

I was expecting some differences however not as big as they were. The watt bike had me doing an average speed of 37Kmh where Zwift had me at around 15Kmph.

What route did you use at the time? Were you going up a virtual incline within Zwift?

Ignore the speed and distance that the WattBike is displaying. Speed within Zwift is mainly comes from the watts you are producing.

A picture paints a thousand words so they say. The route was London

Really doesn’t say much.

Speed and distance within Zwift is determine by what I posted earlier, your WattBike will hardly ever match.

It is difficult to get used to concept once you have ridden on Zwift for a while.

This come up for new Zwifters all the time.


Thanks Paul, I’ve done a bit of cycling in the past and positive I did more than 5 miles :grin: I will have to have a play with it the next time I go to the gym and see what happens. Thanks for your time

Zwift works a little differently and that is something you have to get used to.

I am not just pulling these answer out of thin air, these are know throughout the Zwift Community.


I’m not doubting you mate, as you say it’s going to take some getting used to.

Thanks again