Speed. Sorry, I just don't understand


(Richard Glazer) #1

Dear Zwift, sorry, but I just don’t understand.

I have recently invested in a Wahoo Kickr Snap and a dedicated bike for it and I’m really looking forward to getting into Zwift. I set up the Kickr, upgraded the firmware and everything looks like it’s working really well. I get all sorts of data from the Kickr as expected but I don’t have any other historical reference for power etc except an understanding of the sorts of speeds I am used to seeing (when I use my Garmin in the real world.) This information is important to me and is the reason I made the investment in the Kickr and Zwift.

Why, having identified that I have a Kickr, does Zwift not take the speed directly from the Kickr? Is its speed not my speed?

When I’m riding on a 0.0% gradient road and I speed up, the speed does not really change. Well, it does, perhaps a little (1mph) after some time. Again, when someone passes me and I chose to try to chase them down and instantly speed up in the process, the speed again doesn’t change. It changes when I go up and down a hill but it’s not reflecting the work I am doing, that is for sure. From reading comments here, I can see that speed is not based on speed but power, weight, gradient and other factors. I am not sure I understand this when my smart trainer offers a speed; specially when the gradient is fed back to it by Zwift to affect the resistance and, therefore, my speed automatically.

I would really be delighted to hear that I have set things up wrong with the Kickr or Zwift. Are there any settings that I’m missing here? Your help would be greatly appreciated.


(Eric C. (Zwift HQ)) #2

Hi Richard,

Speed in Zwift is calculated using wattage, gradient, and weight because it is supposed to simulate an outdoor ride. The “speed” that the KICKR is generating does the same thing, except it doesn’t really know what your weight is unless you enter it into the Wahoo App.

The key, here, is to figure out if your actual WATTAGE is changing when you speed up. If it’s not then you might be in ERG mode which holds your wattage to a certain amount and is primarily used in training and, thus, holds your speed consistent to that wattage.

In SIM mode then the resistance of the trainer will change, becoming harder when you ascend and easier when you descend. Increasing your effort will increase your in-game speed.

If this isn’t happening for you, it could be that something is controlling your trainer and not letting Zwift do its thing. Make sure *everything* is closed that isn’t Zwift - any Wahoo Apps on your mobile device, any other kind of training program on your computer, and Garmin Express/Connect if you have it. Then start Zwift again.