ERG Funky In Cadence Drills

Something funky happened during today’s workout “Cadence Drills”, where the target power and resistance were intermittently not working correctly. The issue seemed to be predominantly on power levels of 80 watts or more.

Devices were connected and it was in ERG mode, but it was tough for the resistance to get high enough to produce higher target wattages.

It was working normally during warm-up, but then immediately after one of the first cadence increase efforts, the resistance faltered. The only thing I can think of is that I over spun it and whacked out the calibration? Or is it possible that because I did the full frontal the training effort adjustments aren’t happening automatically?

Here’s a few screenshots showing it doing okay at some points, but not others. I did check to make sure I didn’t have a flat tire and the roller resistance is set. Thanks for any advice !

You’d be best contacting the minions with that question.

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I wouldn’t sweat it. The cadence drills are not about hitting a power target - they’re about neuromuscular training - by getting your muscles to turn on and off very quickly. The load is basically irrelevant.

While we do recommend using Level mode for Cadence Builds, this is odd behavior. If you would like us to dig into this further with you please use this link to contact us: Submit a request – Sufferfest Support (be sure to use the email address you use for the app so we can look at your ride).

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Something I’ve found is if I try to predict a cadence change and ramp up too quick erg doesn’t change to the new power target until I slow down a little. This mostly happens on workouts with big changes in power. My fix is keep my cadence ramp conservative until after I feel the resistance kick in.

@toddsdonald , I will second the “contact the minions” advice, but I will say I’ve had something similar, where the reading will be a little “fluttery” I guess. I’ve found if I pause, then toggle my BT settings, it resolves. I will say it only happens in MacOS, I’ve not experienced in iOS.

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@CPT_A have you been in touch with us about this. I’d really like to look into that more with you, if possible!

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Hi Rebecca, Not yet. I was going to try it again in today’s workout to see if it works properly with a different training session.

Hi pb07, I agree with you and tried to focus on that aspect of it, but also couldn’t help but try to achieve the targets because they must be setup the way they are for a reason. The fast cadence drills are accompanied by higher power targets, (makes sense), but instead of the resistance adding enough drag to create the power, it was essentially free wheeling at around 80 watts. At one point I brought it up to 160+ cadence and still couldn’t hit the power target. Another time, although I shouldn’t have had to change gears in ERG, I did to experiment a bit, and threw it in my biggest gears and cranked up a 115-130 cadence to make sure the power reading was responding, which it did, but way lower than it should’ve been, reading 300 something when it should’ve been probably more like 800+

Your ERG mode certainly seems to be breaking down at high cadence. I find with my trainer that I get an initial power spike above target when rapidly increasing cadence and then ERG corrects itself back down to the target power.

I have on rare occasions seen ERG mode sit well below target power at very high cadence and only correct itself when I reduce cadence and ramp up again. But it’s not something I see routinely, more of an odd glitch. Usually ERG is pretty sharp in following power targets at low or high cadence. But sudden changes of cadence and/or power are certainly the most demanding of ERG and some trainers simply cope better than others with those dynamics.

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Thanks all, it appears to have corrected itself overnight. When I did “Revolver” this evening it worked perfectly, nearly spot on all the time.


Revolver isn’t as demanding on erg as the cadence workouts though - it’s not as extreme. It might just be a limitation of the trainer. I ended up taking a slo Mo video to work out what my actual peak cadence is (~240) because the wahoo sensor drops out around 135, and the trainer bkool sensor drops out around 170. So i end up with a bunch of weird zero cadence segments in my drills. Probably worth doing that yourself, you might find you’re spinning a lot faster than the sensors can actually report - and that might be impacting how the trainer responds

My Wahoo cadence sensor is mounted to my crankarm it has recorded up to 190RPM

, compared to 130 ish when mounted on my shoe. you can in this graph how speed continues to increase despite recorded cadence staying the same or even falling

I’ll pay closer attention next time with spin drills. I’m using a Bontrager cadence sensor via ANT+ and it seems to be very responsive with the Sufferfest. I cannot even imagine spinning that fast like was mentioned. At one point I recorded 161 rpm and had a hard time believing that was accurate, but it did feel like my legs were gonna detach from my hips lol. I think 135 is about the max I’m comfortable with for a short burst. I’m old… Don’t want to injure myself :wink:

@JGreengrass i have it mounted on the closest point possible to the crank. I’ve never put on shoes. I’ve got different cadence sensors on my road bike and trainer.

Now that I’ve worked out what i can actually do, and have a reasonable feel for “good day bad day” I’m not super concerned if it can’t record - my muscles will.

@toddsdonald like what mac says…the point is to do the drill outside your comfort zone. That’s how you trigger your body to respond. If you hit 165 that is awesome. Obviously you won’t be able to hold that for long, but it’ll help you get more efficient at lower (reasonable) cadences.


ERG not smooth like Butter…

Hmmm well, tonight the ERG got funky in “butter” at the worst possible time, at the end right before cool down. It was right as a sprint ramped up and even though I had plenty of RPM (105+) and some leg left, it wouldn’t apply enough resistance to bring it up to target power of like 295 and got stuck at 175’ish. Arghhhh that’s a suffer+ effort there should be a badge for lol. I finished the ride cooling down at 70 something RPM and 175 watts. Finished the workout then did an actual cool down once the software released my trainer resistance.

Yep, I’ve seen this exact thing a few times on my Saris H3. Generally if I put the trainer into level mode then back to ERG it will correct. That process , even though it only takes a few seconds, is not so convienent in the middle of the workout… No idea if my trainer is “missing” the initial command from SUF or if SUF is the culprit. It’s happened to me in Zwift to so I think maybe it’s the trainer, but not sure.

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When my tyre starts shredding it causes static, which mucks things up pretty bad. This usually resolves after about 5-10 minutes of pedalling hard, but I’ve learnt that I need to vacuum the shredded rubber up.

I don’t think that’s the same as what you’re seeing, because once it warms up it seems to settle down though. But if you do have a wheel on trainer it’s prob worth checking if there is any shredded rubber around.

I often do at least one 5-7 hour set on the trainer every week which anecdotally I think is worse for the tyre getting hot and having this problem. I’ve just replaced the last tyre with a new one and it’s not shredding right now… But… I also did both of my long 5+ hour sets outside this weekend because the weather was amazing. I’m sure I’ll get the opportunity to find out soon how the new tyre holds up to a long session… So much rain this year it’s crazy.

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