Speed determination in Zwift

I know that there are many parameters that affect speed on Zwift including drafting, bike, wheels and road surface. Are there any other parameters that affect speed? Does a rainy day, for example, change the speed compared to a dry day? Or the gusts of wind up the mountains? I suspect that the physics are not that advanced but I thought I’d check.


This might help you: https://forums.zwift.com/t/how-does-zwift-determine-my-speed/

Thanks a lot! I have seen this post but I need to exclude the possibility that there are other physics parameters taken into account.

In essence, I need to establish that if a rider who has not lost/gained any weight and who could theoretically produce exactly the same power and cadence, on the same bike/wheels, would cover the same segment in exactly the same time.

@kickRider: I would say the answer to your question is yes, provided the rider is on a TT frame or, somehow, manages to not encounter any other riders along the way (each of which would provide some draft with a non-TT frame and, therefore, alter the speed even at the same power output).


Unless you are comparing to an old time on a gravel route which was ridden before the gravel resistance was added in zwift, They should be the same.