Can I set Kickr as speed source?


(Christian Wiedmann [X] 50) #1

I was very interested to see “power or speed” show up when pairing Ant sensors today.

Is there a way to set Zwift up to use the Kickr’s speed instead of power? I tried, but could not figure out how to do it if it’s possible. The Kickr isn’t listed in the speed sources.

Is Zwift using sim mode in the Kickr so this would provide a realistic experience?


(Jon Mayfield) #2

We do use sim mode, but the KICKR speed doesn’t match Zwift’s, so it’d present an unfair advantage if you were able to use raw speed (which you can’t). The people who can pair speed are those with a common basic trainer and a speed sensor, and we do the power calculations on our end.


(Gary Randolph(BTC)) #3

I’m surprised that the speed from a basic trainer can be selected. Seems like a power curve would be generated, using that speed, but then converted to a Zwift speed based on the power curve calculated for that basic trainer.


(Christian Wiedmann [X] 50) #4

@Jon: ah ok, thanks for the explanation.

Would you consider ever trying to tune the model parameters fed to the KICKR so that the speeds match more closely? I’m presuming you can set all the parameters available through Wahoo’s app over Ant as well, but it seems to me that it might be possible to get close enough to the model you use, or at least as close as a basic trainer power curve would be to real life.

Here’s my lobbying effort: using speed rather than power feels a lot less laggy to me (I also use veloreality’s v_ride which has both options so I’ve been able to compare) and I think it would help the feel of the simulation a lot.

Finally, feedback on the resistance on the KICKR: it feels like either the slope is being scaled or the weight is set too low in the simulation parameters. When riding up the Col, I get 10mph at 90rpm in a 53x23 (should be closer to 16mph according to bikecalc). Is this intentional?

Just to put this in context, I’m really enjoying riding in Zwift. I think it is an excellent service and I’m excited to see it develop.


(Jon Mayfield) #5

Gary, that is exactly what happens if you choose a speed sensor for basic trainers.

Christian, you are very perceptive and you are correct about slopes. We’ve tuned the feel so that it feels more fun rather than striving for 100% accuracy on the smart trainer settings (but the physics are still true to life). We could probably let the user choose between ‘tuned’ and ‘true to life’ feel on smart trainers since it doesn’t actually affect their in-game speed. The 10% grade was kicking too many peoples butts. :slight_smile:


(Gary Randolph(BTC)) #6

Thanks Jon! I knew you guys would do it right. :slight_smile:


(' BTCNJ-Jim-HUBS(D)) #7

Jon Mayfield , thanks for the explanation on the feel going up hills . I was thinking I was really improving , ( not ) . When I first started with Zwift my heart was trying to escape my rib cage trying to keep up with others up the hills . 5 - 6 mph . Your tuning down the slope feel makes more sense now than me picking up 3 mph over the top of hills due to my physical prowess.