Some further trials have me thinking I piled on too soon. I do have a similar experience to @CaptainThunderpants also on the Direto: not the tight second-by-second jaggies we all know and disregard, but longer slower (10-30 second) oscillations above or below target that can change the workout experience. His focus was big ring vs small ring. But both of us focussed more on the Direto itself rather than Power Match, which we also use. Now I wonder if it’s really the Direto, rather than the combination that Power Match is trying to juggle.
Last week I rode Dade -1 with my usual setup: Direto and 4iiii, Power Match on Auto, Erg mode. Here are the first three intervals:
I did all of the workout in the big ring except for the second interval where I tried the little ring. Like OP, there’s a difference in staying on target; unlike him, it’s the little ring that’s struggling! I clearly remember exactly what you see here in the second interval – the power staying consistently below target until the very end of the 2-min interval. I shifted back up and stayed in the big ring for the remainder of the workout. The big ring intervals were better, with an opposite tendency – a spike that later settled down. [Standard practice for erg is to come into the work interval at the cadence you want to use, but if I do that, power actually drops at the beginning of the interval and takes 10-20 seconds to get back up, so I took advice I got in the forum and now wait until the resistance kicks in and then I try to scale up with it – hence the cadence line here.]
Yesterday, after my post, I re-rode the first part of Dade -1 again, to compare with the above. But this time I turned Power Match off and unpaired the 4iiii from TR, so TR was using only the Direto to measure power and adjust resistance. Way different result:
Not quite the phony boxes a Kickr can display, but as close as I’ll ever get. I believe these three are all in small ring but I forgot to make a note, so now uncertain. The Direto alone is not the wobbler.
Simultaneously with this, I also recorded the workout on the 4iiii alone on my head unit. Since this didn’t go to TR, I’ll have to show it in Garmin Connect:
To re-iterate, this is just the 4iiii’s reading of the same exact intervals as the earlier graphic from the Direto alone, not a different ride. The initial surge – which I’m sure is real in some sense – is seen by the 4iiii, but not by the Direto, which is seeing only total power arriving at the trainer.
Since my 4iiii is left-crank only, it’s likely that a left-right imbalance in legs has something to do with this – weirdly manifested over time. I’m sure my left leg is weaker, but also that I tend to lead with it. So two different real time reports, one of them changing, gets thrown at Power Match and then thrown back to the Direto’s resistance mechanism – and sometimes, not always, the experience is weird too.
I also ran these two files through DC Rainmaker’s tool and re-confirmed that the 4iiii always reads appreciably higher than the Direto, a lot higher at 100 watts than at 200 watts – so that changes too.
This is all deja vu of a few years back when I concluded that Power Match was messing up my workouts and turned it off. Then about a year ago I turned it back on – with the same gear – and got more satisfactory results and then just kept my head in the sand until now. Now that I’ve taken it out again, I see from another thread that Power Match is currently undergoing a major overhaul. I’d probably better shut up and go read that whole thread carefully before I turn it off again.
