What is off: my fitness, outdoor left-crank 4iiii, or indoor Tacx Neo 2?

FTP inside: 218 watts. Threshold average heart rate 160-165 (given same level of fitness/fatigue on intervals).

But when I do Stromlo +3/+4 outside, I can easily sustain 250-260 watts instead of the 226 inside with my “indoor” FTP.

Yesterday, did 110km with NP of 188 watts, that’s 3h45 minutes aprox. According to intervals I need full rest day (just tipping in the red). But I don’t feel fatigued whatsoever. Just got of the bike and felt fine.

  1. Is my Tacx Neo 2 UNDERreporting watts?
  2. Is my 4iiii left-side only OVERreporting watts?
  3. Did I gain so much FTP after build? (have not retested yet, went outside due to hot weather)
  4. Is outdoor FTP SO different from indoors?

You need to clarify exactly what power data is coming from:

  • Inside: Neo only, or are you using PowerMatch with your 4iiii on the trainer too?
  • You mention this here, but never reference it again. How is this related to the other situations?
  • Have you ever used them at the same time, with different devices to see if there is a differential between them? (Guessing not, but want to be sure.)
  • Entirely possible, as is the common issue where people sometimes have “more power” when outside. It relates to things like cooling, motivation and such, but being able to exceed power compared to inside is common.
  • You really need to test inside, with the same settings and variables as your most recent test, to have any hope of comparison.
  • Maybe. As mentioned above, it can vary for many people, but not everyone. Some have equal power in/out, while it varies for others.
  • Knowing how you have handled it in the past (in/out) is helpful to know.
  • Do you consider you inside setup “optimized” in the sense that you have REALLY GOOD cooling and motivation to hit power targets?

We need more info to be able to give more useful answers.

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Inside only Neo 2.

HR same inside as outside for this ride, the assumption being that the watts are off, because apparently inside is as “taxing” as outside at 160-165HR, but outside with much higher watts.

No, indeed, good point. How can I do that?

Makes sense. For me inside feels disproportionately harder than outside. And I have checked my Tacx and bearings etc a hundred times already to make sure my Neo2 is not faulty or anything. Must be ERG-mode and requirement of constant pressure or something.

Yeah, thanks, I know. I only test inside. Outside I just adjust my watts on the fly based on my heart rate and try to compare watts with inside heart rate (e.g., threshold inside is 165HR at 225watts, so outside I can go 250-260). Zone 2 / endurance for me is inside 150, outside 170-175 watts at 140HR approx.

Cooling could be better I suppose. I have one big desk fan blowing very hard right in my face, and I sit next to the window with it opened fully. But in the summer that may not be enough perhaps, even when you go in the morning or evening.

Also, I am extremely consistent with ride times. Inside, I ALWAYS go around 16:00-16:30. Have been doing that for a year. Also already factored sleep and nutrition into the max. That is the same inside as it is outside.

  • You’d need to install your bike that has the power meter, onto the Neo. Then record power for both devices (trainer and meter) at the same time, with two different devices (mix of phone, bike computer, laptop, etc.) to capture the data from both devices at the same time.
  • You can do a “ballpark” comparison by simply watching power reported from each device. Ride a range of power points from Endurance to Threshold and over VO2 max to see what the data does across the power range.
  • Better, if you want more work, is to do a data comparison with something like the DC Rainmaker or ZwiftPower tools, to overlay the data from each device. You can dig in and see exactly how and where they differ.
  • Entirely possible, as some people struggle with the loading from ERG mode vs Resistance or Standard (Level) modes.
  • It may also be influenced by the gearing you are using.
  • What gearing do you typically use?
  • Also, have you set the appropriate rider weight in the Tacx Utility app, so the virtual flywheel is adjusted for your weight?
  • We often see people say their cooling is fine. But all too often, they have a single, average flow fan that is not properly cooling them. If you have a large amount of sweat on your body, and pooling under you, it may be a sign of insufficient cooling.
  • I have 3 of the large, high flow Lasko blower fans on my (1 on my face, 1 on my torso, and 1 on my back) and rarely have a single drop hit the floor under me, even with my toughest workouts. Point being that I work hard to get LOTS of air flowing over my body to get the sweat to actually evaporate off my body and cool as intended.
  • One fan on your face only leads me to suspect you are not getting proper cooling on your core, and could be limiting your power.
  • That’s great and can be a factor that affects results too.
  • I know my weekend morning workouts are always tougher (higher RPE and HR) compared to my weekday evening workouts.
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Will try that out!

Always when I go inside after weeks training outside, it feels sluggish and unnatural before I am adapted to the “hard resistance” feel. When I go outside again then after, let’s say, weeks of build I am always like “this is so easy”.

I have Ultegra SL 6600, so triple in front and 10 speed in the back. So I put it on the middle ring front, and the gear (9th I believe from inward) so that the chain is perfectly straight.

Nope, never did. I wasn’t even aware this is possible! Definitely should check that out.

Definitely a problem in my case. When I do threshold or VO2 sessions, I’m always soaked like I have been in a heavy rain shower.

I should definitely fix that. Can you send a picture of your set-up for cooling? Or comparable example?

  • Great gear, but a bit lower in the “flywheel speed” world. This can sometimes make the pedaling feel “easier or harder”. But that is highly individual and part of the overall ERG mode gearing discussion. You can experiment with higher gearing to see how it feels and adjust if needed.
  • The main recommendation I have is that if you use ERG mode and the Ramp test, it is a good ideal to test in the same gearing you plan to use most of the time in training on the Neo.
  • This pic is a bit out of date. I have the two front blowers the same. But I now have another large blower at the rear instead of the 18" circular shown here. The blower fans just push so much more air than the circular ones.

  • This is my post with a summary of many Lasko fans for cost, size and flow (missing in some cases) so you can consider the other options.

  • Looking for cooling fan recommendations
    I’m also pulling air from the front window (whenever it is colder outside at least) to get fresh and cold air flow pulled from both front fans. I have them set for flow control to limit it in the coldest temps, but it sure is nice to have access to fresh air in an otherwise stale small room.

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Thanks for all the info. Should be plenty to do some appropriate changes! :+1:

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Ok i’ll bite…what is the trail mix setup all about?

It is the vent / louver for controlling the amount of air from the window to the side/front fan. I’ve rerouted the ducting and made a direct flow box on the fan intake, vs the passive low pressure design of the trail mix box. Help pull air from the window much better now, is more sleek and painted black as well for a bit less of a redneck look :stuck_out_tongue:

The top fan has a sneaky cereal box (painted black for black ops :wink: ) to pull air in too. I can balance the amount of air from the window via both systems.

You really can’t compare power meters. My vector 3s reports power 50W higher than my neo. I trust my vector 3s because my power and speed matches with other vector 3s users having similar fitness in my local Wednesday nights. I only stick to my vector 3s for training, and use my neo just for ERG.

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