20 Minute FTP on Smart Trainer: Resistance Question

On the 20 minute FTP test - when it switches to Resistance Mode, how do I know what the resistance should be set to? I looked in the device settings and the resistance is set to 33 which I guess is default for a Kickr?

Im curious if the resistance selected will result in a different FTP that doesnt correlate to ERG mode.

Yup, that is where you go to set the starting value. 33% is a decent value for most riders, and allows shifting to fine to the actual power when needed.

  • Thatā€™s an interesting question, and ā€˜noā€™ is the common answer.

But, when we look at things like flywheel speed (which relates to the Resistance setting and the gearing a rider uses to hit their power targets), we can see some potential impact on the ā€œFTPā€ between max or min flywheel speed. There is no universal answer here. But there is a general sense that people feel a difference in the pedals and possibly muscular loading between max and min flywheel speeds.

If in doubt, the 33% is a good figure and quite close to what I use when in RES mode.

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Is resistance roughly equivalent across different brands of trainers?

Iā€™ve been wondering about users resistance settings for a while now. I donā€™t use erg so am not too fussed on that part of the equation, and I assume/hope that Watts are Watts and that say 200 or 300W should be accurate/the same whether Iā€™m at 15% or 50%?

Watts are watts and if you are on the same device(s) for testing and training you shouldnā€™t fuss over this.

However - as Chad pointed out - different strokes for different folks. I wouldnā€™t recommend this for a 20min test, but on another ride/workout or an 8 min test EXPERIMENT. High cadence is better for some people (saving their muscles) where some get better turning a bigger gear at a lower cadence (saving their lungs and HR).

So while watts are watts, you might personally be able to accomplish more watts using one method or another.

You might find that a massive resistance, little gear, and more muscular effort works for you. You might find that little resistance, pushing a big gear and a high cadence works better for you.

Yeah, itā€™s funny you say that as itā€™s sort of why I started thinking about it. I was at 20% and went up to 21% to move one gear back up my cassette with my last FTP increase. I recently tried to go to 22% and found the effort significantly different (and I couldnā€™t get my cadence/effort syncd up.

21% seems low, but Iā€™m pushing out ok-ish Watts so it made me wonder.

Personally when I do a 20min those last few moments are finding any and all means to get another watt. Shifting, resistance, prayers, all fair game.

Offtopic - try the ramp just once or twice. I think it reduces the likelihood of this type of personal variance leaving something on the table for most people. Youā€™ll find ERG works better (or if you use resistance its must less movement) and if you are OK with the results vs. your 20 min, you just got a whole lot easier protocol

My new coach told me to do the 20 minute FTP test.

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  • I canā€™t say for certain, but I donā€™t think it is consistent if you mean that in relation to the ā€œpowerā€ it takes to ride at that percentage setting.

  • My overly simple way of looking at the RES setting is that the percentage is essentially related to the max resistance of the trainer on offer.

    • For a trainer with a 2000w max resistance, 50% would be around 1000w resistance.
    • For a trainer with a 1000w max resistance, 50% would be around 500w resistance.
  • This is what I believe is a past understanding in the world (most often quoted in relation to ERG mode), and one I feel is not correct.

  • As mentioned, I firmly believe that flywheel speed can be something that is at least felt. We have seen many comments from users that they can ā€œtell the differenceā€ in feel of the pedals at the same wattage, but at different flywheel speeds (max vs min and somewhere between).

  • I make no claims that any of this will yield meaningful differences in training effect. I have no real evidence other than my own feelings. As such, I choose to try and apply a flywheel speed that makes sense and aligns with my needs outside on the bike.

  • So, long story story, I feel that gearing matters to some extent, even if the power is identical.

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Iā€™d recommend experimenting before doing the FTP test. My FTP is around 250W and 33% is a good place to start experimenting on my Kickr 2017 direct-drive. Free Ride is a good workout in the TR library to use for playing around with resistance until you find a good combo of resistance and your personal preference for cadence on a 20-minute hard effort.

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As above, have a couple of test (short, not 20min!) at different resistance levels.

I think it probably doesnā€™t matter for riding at FTP (unless itā€™s extremely high or low), but the resistance level might be more important for sprints etc. I think it should be set so that you can hit all power levels with your existing gearing, without hitting any power floors/ceilings.

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Thanks for the suggestions! I did the free ride luckily. The gear I had it in would not have worked. Did the FTP test and my FTP increased by 11% in 12 weeks.

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I hate the 20 minute test but I always think Iā€™ve over-paced it. Nailing it is going to be 20 minutes at 105% which is just hard for a long time. If you start off too optimistically then you are screwed 10-15 minutes in to the test.

Iā€™ve enjoyed the kolie moore baseline test (35-45 min) much better since itā€™s a ramping effort. You also feel like you really found your steady state.

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I experimented myself and found the 2x8min was my fave. Iā€™ve since gone to the ramp test just for the quickness of it all but frankly havenā€™t seen as great of gains (which I attribute to many other things).