Resistance Varying with Terrain


I don’t know whether this is a feature request, or a request for how to accomplish something already built in.

I have a Wahoo Kickr smart trainer.  I like having the video of where I’m supposedly cycling, but I can find no way to set it so that the resistance varies with the terrain–I would like the resistance to build as a gradient increases, and decrease as the gradient decreases, so that it’s more like actual cycling.

All I’m able to do is either ERG training, where the resistance is set, irrespective of terrain, and the varying terrain only affects the deemed speed, or turn ERG off, and the resistance is constant, with the watts varying with how hard I pedal and/or what gear I’m in.

I want an option where I have to shift gears as the terrain changes in order to maintain a steady cadence.

Is this possible now?  If so, could someone give me detailed instructions on how to accomplish it?



Do you have the Kickr connect to Zwift as a Controllable Trainer or just a Power Source?

Take a look at this search to see if any can assist you:*


I have it connected as both.  Clearly, Zwift controls the Kickr, as it changes the resistance according to what workout I’m running. 

But the question is whether there is a setup which makes it so Zwift changes the resistance as the terrain changes, not according to a pre-programmed workout.  I want to ride on one of the courses, and, as the terrain changes, so does the resistance, so I have to downshift as it gets steeper, and shift up as it gets less steep.

I see that there is something referred to as “SIM” mode, which seems to be what I’m looking for.  How does one use that, not using a workout?

Change the difficulty setting in Zwift to MAX from 50% default, and make sure your personal weight is accurate.  I did and terrain percentage is accurate on my Tracx Neo.

Thanks, but I don’t think that this is my issue.  I know of no other way to use the Zwift app on my laptop, with the video of the course I’m riding, other than the workout mode, and the workout mode, by definition, doesn’t seem to allow riding in SIM mode.

Assuming Zwift supports SIM mode, how do I set things up to be able to do this?

Instead of selecting a workout, just select a course and route to ride that should put you in SIM mode.

Here is the unofficial Zwift manual:


Ok, so if I ignore “workout,” select a course, and then click on start ride, it should vary the resistance by terrain?

If so, does it use my calculated FTP for deciding how much resistance, or my weight/height?

It should.

The resistance is determined by the incline/decline of the virtual terrain. In “SIM” mode your FTP does not matter, but may change based on your output during the ride (usually up if it does change). You weight and watts will determine your w/kg which in-turn dictate your speed on inclines/declines. The virtual bike will also make a difference in your speed in-game. 

That worked; thanks very much!

I have had issues where my workout did not set an option in the zwo file correctly. You can manually change this for a self made workout. Here is an example:
<FreeRide Duration=“180” FlatRoad=“1”/>
change the Flatroad=“1” to Flatroad=“0”

0 is ‘SIM’ mode and 1 is manual, you determine the resistance by gear (which is what I want)
I raised this as a ticket but the person responding really didn’t want to admit that this worked or that it could be done and ‘it is not supported to manually edit a zwo file’. Well that is a really poor response and quite frankly I couldn’t be bothered to respond. There is a bug where if you don’t have a controllable trainer attached an you create a workout with a freeride in it it may not set this correctly and it ends up in SIM mode when you do connect an ERG trainer…