Unstable power with Elite Direto XR-T in ERG mode

I’ve recently upgraded to an Elite Direto XR-T and am struggling to get it working properly. I’m running Zwift on a MacBook Pro (with the Companion app on Android), using Bluetooth to connect. The first time I used the trainer, I did a spindown calibration in Zwift, after warming up for 10-15 minutes.

Today was the first time I tried a workout in ERG mode and it was a complete mess. The power values were fluctuating wildly, +/- 10-15 W or more from the target value while holding a steady cadence. This lasted all the way through a 1-hour workout – so frustrating! At its worst, the target power was 120 W at 90 rpm, and my power was rising as high as 146 W before falling back down to ~100 W again. Honestly, my old wheel-on trainer was much more pleasant to use in terms of power stability.

After the workout, I tried calibrating the trainer again, this time using the My E-Training desktop app and it gave an offset of 6670, which exactly matches the calibration offset on the sticker on the trainer.

What else can I do? Is it possibly due to an unstable Bluetooth connection, or is there something else I should check before shelling out for an ANT+ dongle?

I just set up my Elite Direto XR-T and Zwift and took it for a spin and FTP test. Seems like I ran into the same problem.

When trying to maintain a steady watt output I could feel the resistance fluctuate constantly (screenshot attached).

I run Zwift on a MacBook. Companion on iPhone.

Does anyone knows whether it’s the Bluetooth connection? Zwift? Or the trainer itself? All help is much appreciated.

Since I made my original post, I’ve done a bit more research and this seems to be a “feature” of the Direto XR. Essentially, the trainer’s precise power measurement capability also translates to excessive fine-tuning (i.e. the yo-yo compensation) in ERG mode. This seems highly undesirable, IMO; just because the trainer can measure the power at fine-grained intervals doesn’t mean that it should automatically update the resistance in reaction to every little fluctuation… But it can be mitigated to a certain extent by increasing the power smoothing factor in the trainer settings. I’ve managed to get the fluctuations down to about 5-10%, which is more tolerable, although certainly not ideal. (Note that this is absolutely useless for short sprint intervals.) There is a very long discussion about it on the Elite forums, but it doesn’t seem like Elite are actually doing anything useful to correct this issue in the firmware.

http://forum.elite-it.com/viewtopic.php?f=34&t=2530&sid=138fd13c6c6e0bbe7496682031852ece

1 Like

Hi Kate,

Thanks for the update. I’ve read through the forum and power smoothing seems to help a little. But the compensating remains very annoying…like someone constantly hitting and releasing the brake. Seems like there is nothing more to do about it.

I’ll see whether I get used to it in a week or I am going to return it and go for a Wahoo Kickr Core. If I knew about this ‘feature’ I would have gone for the Core right away.

Thanks for the info, cheers,
Tom

Hi Tom,
That does seem really annoying. My Direto doesn’t usually overcompensate to the point where I can actually feel the difference in the resistance! I’m just bothered by the numbers fluctuating on the screen. :sweat_smile:

Have you tried contacting Elite support? Some people in that thread I linked above did have some success after getting in touch with a support tech and doing some diagnostic tests. It might be worth a shot.

Hi Kate,

Thanks, I will try to smooth the power and see if it helps. Otherwise I might reach out to the support of Elite or return the trainer. Either way, looking forward to staying in shape this winter.

Thank you for the help,
Tom

I am also having this problem, but it doesn’t get easier again. Half way through a work out it just became almost impossible to pedal, even standing up, and the only thing I could do was switch it off and start again. Very frustrating. Don’t really know where to begin!

That sounds like the “spiral of death” where you reduce your cadence and so the resistance increases to compensate, then you struggle with that increased resistance and your cadence drops a bit further, then resistance increases further. Rinse and repeat until you literally can’t pedal any more.

So is the answer to not let your cadence drop??

Basically, yes.

Or to at least be aware of the spiral of death, so that when the resistance increases and your cadence does drop, then you know that you need to push to create the set power level, and hopefully the resistance settles and you can keep your cadence.

If you know about the spiral of death, you can probably do enough to keep away from it. It’s non-intuitive because it’s the opposite of what you experience when riding outside.

Outside, when you pedal more slowly, then the resistance decreases and when you pedal faster it’s harder. But it’s the opposite in ERG mode, so it takes a bit of getting used to.

OK - thanks! I’ll bear that in mind :grinning_face_with_smiling_eyes: