I can't take it anymore...back to my KK Road Machine


#41

That is correct, I can hold 90 rpm very consistently, but the snap never seemed to like that cadence and would generally slow me down to another slower cadence.


#42

You’re right that’s an awful experience. I’ve been using Wahoo trainers for 3.5 years (original Kickr and now a Kickr Core) and I’ve never experienced that so it sounds very strange to me


#43

I had the same issue…even in a 120 watt rest interval…if I tried to pedal 90 rpm…it would slow me down.


#44

Huh, Snap user for 14 months and don’t have that issue. I only focus on cadence consistency though, never even consider the power since ERG handles that. Yes power is +/- 1 watt but it never even occurred to me to adjust my cadence to corrrect it. Maybe it depends on what chainring and cog you’re in :man_shrugging:. I train on my MTB so my gearing on the trainer is 32 x 16. I haven’t experimented with other gear selections.


#45

I do, and I may yet return it to have a good Fluid2. I long ago got rid of the box and such - it’s fifteen years old - so I don’t even know if they’ll take it!

I wanted a smart trainer and the leak was a sign. :smile:


#46

I only focus on cadence too. With the new trainer I can put on some 90 bpm music and hold it steady, I don’t really look at watts only time near the end of an interval when I’m counting it down.


#47

First paragraph is how TR’s PowerMatch works. In Erg mode the TR app simply sends target power and lets trainer handle everything.


#48

I’ve had my Snap for 2 years now and it has been great. Connected to PC via USB ANT+. The only concession I’ve had to make is to use a 10 ft USB cable to account for the poor ANT+ protocol broadcast. Otherwise, I have no problems with death spiral, don’t need to spin at 105 RPM (though I try to esp. early in the workout) and I do 95% of my indoor riding using ERG. Even on easy days, I’ll have TR drive an easy workout like Petit to keep me from pushing too hard. I also have an old (10+ years) KK Road Machine and also started Zwift & TR with it. Would never go back. To each their own though.


#49

I think I may have experienced that - Kickr increasing the resistance together with the cadence. But it only ever happens when Kickr is not paired to any controlling device in my case. As an example if I get on a trainer and start pedalling while PC is booting up. The resistance is pretty high already and if I try to pedal faster it tries to stall me.

But once paired, everything goes as requested.


#50

So the death spiral is shooting handheld f/8 ISO100 outdoors at night in aperture priority and wondering why your shots come out blurry?


#51

I am the same amount of time with my snap. I used to have braking come on and not let go at the start or end of an interval when i was using bluetooth connection. Kind of odd but upgraded the firmware and started using ant+ and have not had any problems since which is about 1.5 years now.

I did have a road machine but sold it to my Dad and he loves it. I was actually thinking of getting another one for my daughter to ride. She is active in sports but would be fun for her to ride a little while I am training.


#52

Right, except that introducing the power meter data, and then having to adjust the trainer resistance based on a potentially different power slope (meter vs trainer) adds a complication since it is likely not a 1:1 adjustment in many cases. It is the same, but more complex with the 3rd variable in the process. The presence of the PM via PowerMatch is a real change, even though they are theoretically the same.

There’s a reason that we have several threads discussing the effectiveness (or lack there of) for PowerMatch. It changes the overall picture of how ERG works enough to cause issues in some (many?) cases.


#53

@mcneese.chad guess I’m a little confused by your comments, and trying to clarify for others benefit. Erg mode on a direct-drive only requires the app or bike computer to send target power. The app simply:

  • sends target power to trainer
  • records power reported by trainer

And all adjustments to resistance are handled by trainer’s Erg mode. The control loop is entirely inside the trainer, assuming the trainer has power estimation. From my understanding of Erg and talking with Wahoo, that is how it works.

The actual link (ANT+ or BLE) between app and trainer is far less important from a user point-of-view. A standard like ANT+ FE-C makes it much easier for TrainerRoad and other apps to control the trainer, but the control loop itself remains inside the trainer.


#54

True for the most part, but the addition of an external power meter alters that situation. I may well be wrong, but here is my understanding:

  1. Without PowerMatch

    • The power data value in use by the trainer comes directly from the trainer. It is a 1 = 1 relationship that 1w change from the app leads to a 1w change from the resistance unit. It is as straight forward of a relationship as possible because the input and output are effectively “the same” via using the same “measuring device/trainer power meter”.
    • I do think this is relatively “simple”.
  2. With PowerMatch:

    • The power data value comes from an external power meter (not the trainer). This can lead to a variable 1 = ??? relationship because the power meter and the trainer likely do not have the same power data slope. As such, if the app says change 1w, the resistance unit on the trainer may well have to change by something other than a simple 1w.
    • This differential varies because the power meter and trainer don’t always report the same power data at all times. It is likely to vary, and that variation is also often not linear.
    • I’ve been talking about the PowerMatch part of this because I believe that was an important variable in the issues that Craig experienced (as well as a possibly defective trainer).
    • I just think that adding PowerMatch leads to potentially different (and less desirable) results compared to using the trainer-only power meter option in #1 above.

I am likely explaining this poorly, and I’m not sure how to state it any better/differently. But the whole process changes in a significant way once you introduce PowerMatch and the associated power meter. Even if you use the built-in PowerMatch that is part of some Wahoo trainers, you still have the continuous differential between the trainer and power meter at play.

It’s like taking a simple calculation and then saying every time you run that math, add “2” to the ‘X’ variable for power. But in this case, that ‘X’ variable is most likely not a constant variable.


#55

I think what he means is that when power match get added into the mix, something has to adjust the power request to the trainer to ensure it matches what is being recorded by the power meter. So either somewhere in the app a match table magically appears, and it runs open-loop (adding a delta to its power request), or the app has to close the control loop between power meter measure and request to the trainer. I haven’t seen the software so I can’t say how they do it, but I suspect it’s the latter method.


#56

@mcneese.chad Yes, there are two basic cases:

  • Erg mode
  • Erg mode with power match (either Wahoo, or TrainerRoad)

In classic Erg mode, the trainer is responsible for:

  • receiving target power from the app
  • estimating current power
  • making changes to resistance

With Wahoo “Control w/ANT+” all that changes is the trainer is getting current power from another source. In this case, just like classic Erg, Wahoo is completely responsible for controlling the resistance of the trainer.

TrainerRoad’s PowerMatch is different of course, as now TrainerRoad is responsible for controlling the trainer resistance. And to the trained eye you can see it struggling to do that, from time to time. But it generally works well.


#57

You’re describing an open loop control, when in reality the trainers are using closed loop control.

There are multiple variables that could influence why Powermatch doesn’t work as well compared to not using it. I’d guess it’s mainly due to differences in time constants and tuning the control parameters.


#58

Right, I am not claiming to have this exact in definition.

Over-simplified:

  • ERG on it’s own = simple / easy
  • ERG with PowerMatch = not as simple / not as easy

They both have the same goal, but the subtle differences can (and do) lead to slight differences in results for some people.

That is the reason I brought it up, as the OP was working withing the PowerMatch realm (via TR if I’m not mistaken) and I think that may well have negatively influenced his results. It’s one of many variables that lead to his overall experience, and worth consideration in the diagnosis.


#59

Right, and to make matters worse, the “Kickr” family includes the wheel-on Snap (original poster) and the higher-end direct-drive units.

Sometimes I read “Kickr” and assume it is the same as my direct-drive unit. The Snap behaves differently from the direct-drive unit.


#60

I have both, and I like the idea that a KK will basically last forever. I definitely still use it when travelling, and sometimes just for something different. The ERG trainers, while good and do have merit in terms of ease for interval workouts, the fact the Kickr seems to have a new model every year, is an expensive hobby. I don’t mind working on maintaining my own power for intervals on the KK, it seems to help pass the time.