Should I connect my Computrainer to Zwift or just use erg mode?

tonight was the first time I rode and I just launched Zwift and it found my quarq power meter and 920 HR monitor. I just put my computrainer on ERG mode and the desired watts. What was weird, is for the first part of my ride my speed was really high and watts and HR seemed about right, then the second half of my ride it seemed like it was really hard to generate any speed at the same power… Can you connect the computrainer to Zwift so it will adjust resistance according to elevations? If so, how?

Pull the ANT+ dongle out and go through the same Pairing. I just replied to another …see that answer. Your CT will be controlled.

If you tell your CT to hold a certain watts, then your speed will go up when you descend a hill in Zwift and speed will go down when you go up a hill. I use a Kickr with Zwift and it’s not intended to be used in Erg mode with Zwift. Instead, it’s used in sim mode where resistance is controlled based on your weight and the current simulated grade. You then shift as you would on a real road outdoors.

I’m not certain if CT is compatible with Zwift, but if it is, it would be best to use it similarly. Now, if your intention really is to hold the same wattage for your entire ride on Zwift, then you can use erg mode to do so. Just remember that Zwift will change your displayed and recorded speed based on the grades.

Also, if you want Zwift to control your trainer, you need to select it as the power source, not your power meter.

CT works great with Zwift. I use it both with the terrain controlling power and in ERG/SLOPE mode controlled by TrainerRoad. This is useful if you are doing an active recovery ride and you don’t want to raise the h/r too much on the hills.

As Christopher said, just pick the CT on the power source screen.

The problem with that is some riders like to pair their power meter rather than the computrainer as the power source.  The power meter and computrainer will often calculate watts differently and riders want to be consistent whether they are indoors or outdoors. Also, riders want to track their progress over time with the same power source.

Right now, TrainerRoad is much better for workouts using erg mode, because it has the functionality of controlling the resistance while pairing to a separate power meter.  It would be great if Zwift could do this as well.

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Brian H. My CT gives the same figures as both Stages and my P1 power meters so I don’t have any worries about different readings. What others could do is do a run using CT power and compare it to their pm output and if there is a difference they could adjust their FTP on Zwift so that the workout comes back in line with their actual power. This would let them still use ERG in Zwift and trust the power is correct. I always have my pm paired to the Garmin to check as well.


Thanks Stewart!  That is a good idea!  I need to retest soon anyway, so I will run them parallel like you mentioned.

As long as I do a proper calibration mine is bang on right through the power curve.
Just look at your CT and pm test figures and just adjust the FTP slider on the Zwift workout screen to allow for any difference. If the CT was reading 20W high then just increase the slider by 20W so that your actual power will be the levels you want.
I enjoy both ERG and slope style workouts and it is a shame that many miss out but by using this workaround you can still do them on Zwift.