Depends on how much you vary it...
If I'm doing vo2 intervals and I'm going from 55% FTP to 115% it takes about 10 seconds before the p2m (garmin) reads the same # of watts as the target for the interval. My garmin is configured to show 3s average so the 10 seconds delay could be less. I'm also spinning at >100rpm during the vo2 intervals from my normal 90rpm.
If you're just changing cadence slightly there's a 2-5 seconds delay before you see the kickr catch up with it. It's actually pretty OK, you don't want the delay any shorter because then you'll have the kickr constantly put on the brakes which would be annoying.
If I'm doing vo2 intervals and I'm going from 55% FTP to 115% it takes about 10 seconds before the p2m (garmin) reads the same # of watts as the target for the interval. My garmin is configured to show 3s average so the 10 seconds delay could be less. I'm also spinning at >100rpm during the vo2 intervals from my normal 90rpm.
If you're just changing cadence slightly there's a 2-5 seconds delay before you see the kickr catch up with it. It's actually pretty OK, you don't want the delay any shorter because then you'll have the kickr constantly put on the brakes which would be annoying.