I just did my first ramp test on a Tacx Flux2. Just switched to this trainer from a fluid trainer so I’m still getting used to ERG mode.
I did my test in ERG mode but I’m utterly confused after. It felt like it was forcing me to hold a higher cadence (90’s) then what I wanted or typically would as the resistance increased. I didn’t get near my HR or near a perceived hard/max effort because I couldn’t hit the target power number at that high of a cadence. Is that the point?
There are two main factors in erg mode to hit a target power: resistance and cadence. The trainer is constantly adjusting the resistance to maintain the target power as you have natural variances in cadence.
Since power is essentially force x speed, sometimes if I’m not paying attention, I find my cadence drifts higher to reduce the force required of my legs (same force and higher cadence = more watts).
The best way I’ve found to deal with this is to gradually bring your cadence back down and let the trainer keep the power target. If you try to suddenly jump down to a lower cadence in erg mode the trainer is going to respond with a big and sudden adjustment in resistance, which can be killer at the end of an ftp test when you’re barely holding things together
Be patient, don’t try and chase watts, regulate your cadence and the power will adjust to the target. Alternatively move down a gear which disrupts the power but again you need to regulate your cadence so the trainer has time to regulate the power.
As previously mentioned youlll need to concentrate to hold the power but once you get into the groove it’s pretty consistent.
Finally don’t forget to calibrate the trainer prior to every ride
I find my cadence on the trainer is naturally ~10rpm higher indoors - perhaps the same is true for you. I’d have to focus to ride as low as 90rpm indoors (my usual cadence outdoors). I’ve never found a problem transitioning between the two though - just do what comes naturally IMO.
My best guess is that as you are trying to bring your cadence down to where you like it that power is dropping off. Then you are probably increasing cadence to get power back up. So it would seem logical that it wants higher cadence to hit targets. There will be a lag with any trainer in ERG as it adjusts to changes in cadence so my advice is forget about the power and just focus on riding at the cadence you prefer and ERG will sort out the rest. It will vary up and down as you go but try not to think about it too much and just be smooth.
To reiterate, rule #1 in ERG is to hold your cadence at your prefered RPM and do so with steady control. YOU are in control of your cadence, not the trainer or ERG mode.
Since I don’t see it mentioned, you may also be experiencing an issue related to gearing. Some trainers have a “wattage ceiling” that limits the resistance it can apply, particularly in lower gears. Many apps and trainers recommend lower gears for general use, but those lower gears may limit the peak resistance level and appear to “max out”. In those cases, it’s necessary to use a higher gear on the bike.
So, consider your gearing used and determine if that may have played a part in this case. I am pretty sure that the Flux has a ceiling and will run into issues at some resistance levels for some riders.
And to share a common resource I recommend for all new ERG mode users, this is a great watch.
The advice you have received here from other athletes is super helpful! Thanks again guys .
I have a couple of things I’d like to add, specific to the Tacx Flux.
Gearing for the Tacx Flux
Tacx recommends a very specific gearing ratio to prevent Wattage Floors / Ceilings on this trainer.
Let’s have you try a middle-easier gearing combination on the Tacx Flux. Tacx recommends a gearing combination of around 39:19, as this will ensure you’re able to access the most upper and lower resistance levels. Let me explain what I mean. The Tacx Flux has a resistance limitation where, with a certain gearing combination, you may be able to hit high targets, but you won’t be able to hit recovery valleys. It also goes in the other direction, too. If you’re in too easy of a gear, you won’t be able to hit the harder targets. The fix for this is to switch to a middle/easier gearing combo .
Some Tacx trainers experience an issue where, the trainer will not operate well at lower temperatures. The solution to this is to update the firmware, or warm up the trainer for 10-15 minutes before riding. I don’t think this is the issue here but it is worth keeping in mind. To address this, I would also suggest you ensure that you are always on the latest firmware. You can check this in the Tacx Utility app.
General Erg mode recommendations
Connection between the trainer and the TrainerRoad app- as you have noticed, Erg mode relies on a strong connection between your trainer and the TrainerRoad app. Try the steps in this article to ensure interference from other devices is not impacting your connection: Device Dropouts.
Cadence- anticipate upcoming intervals by slowly ramping your cadence before the interval begins. You should ramp to your desired cadence that you’d like to maintain during the interval. This will help you be able to manage the upcoming change in prescribed power.
With the exception of the previous point, it’s recommended to maintain a constant cadence within a range from 80-100 rpm during your workout. This is the best practice unless otherwise stated in the workout description and/or text.
Let me know if anyone has any questions! You can reply here or shoot me a DM
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