This week my wife has been using her new warranty replacement Kickr. It works great, smooth, quiet and power now matches her Quarq. but shes noticed that during the rest between intervals the power stays higher then prescribed. Its set in erg mode with powermatch disabled, quarq is only used for cadence. The power is correct during the interval, but about 10w higher during rest. you can see it in the attached screenshot. I’ve never seen this before. it does not do it on mine or when my son uses mine at lower power. this ride was done at 95-97%
She’s hitting the resistance floor of the trainer. In erg mode, the app demands a power output, and the trainer modulates the resistance setting to deliver that power. But once the trainer is down to its minimum resistance, it can’t go any lower. The first thing to check is which gear you’re on: if you can shift down, do so, it will lower the trainer speed and the power. If already on the lowest gear, then your options are a) accept it, it’s not the end of the world, or b) change the cassette/chainring to give you a shorter gear if you really feel it’s an issue.
I thought that was it but the prescribed was 70w, my son on my last gen kickr will go down to 50w in a similar gearing. middle rear cog and 53t. Maybe the floor is higher on this Kickr compared to her last 2018 or my 2016?
The actual gear used (and the cadence, of course) makes a big difference . A 19 vs 21 in the back is 10% difference, which will make 70W turn into almost 80. As long as you have shorter gears left, you can shift if the power not matching the demand is an issue.
Could be your son was spinning slower than your wife. Cadence affects the power floor. Either way, 70w is really low, downshift that big ring and it will fix it.
Edit: I also like front derailleur shifts for interval changes because it makes me get to the prescribed power faster instead of waiting for ERG to get all the way there. I upshift 3 seconds ahead of time and downshift right when the interval ends.
I agree - anything below 100W is good enough as far as I’m concerned. You’re recovering, it does not really matter if it’s 80 or 90 or 70W. On the other hand, my Tacx Flux S has a pretty high resistance floor, which combined with the relatively long gearing of my ancient 7-sp bike (39x21) makes the power floor somewhere around 135W at 90 rpm when the trainer is cold, going down to 115W after 20 minutes. I’m converting that antique into a 10sp as soon as I find the time - a cassette, a pair of brifters and a chain have landed home last week. I’ll get a nice 39x28 low gear for those rough 5:30 am warmups.
Thanks for the responses. Yes it may work with my son because he is on a 52t with a junior cassette 14-28. So yes his is a few teeth larger in the middle. I agree also about it not mattering, she did not care about the power, just had never seen the line before. It’s just weird that the floor between two 2018 Kickr’s is different.