Dumb Trainer Resistance

So I’m working on a dumb trainer, yeah I know, that’s sooo 1974! Whatever.

Question is regarding resistance, mainly while doing bursts/sprints. I’ve read the linked topic but doesn’t quite answer 100%.

Problem comes when doing things like short sprint efforts, the 5-15s stuff. I have the resistance set to ‘real road’ but I max out on gears before ever maxing out on power (because there is no wind resistance).

If I notch up the resistance, does that effect the whole power profile/FTP setting etc.? Or is it simply a matter of power is power and I should do what allows me to physically max out vs mechanically max out?

Finally, if I notch up for my next ramp test – not that I need to, but if I do, will this give me a kind of false FTP reading because the settings/conditions are not the same as previous tests?

TIA to all.

  1. What exact trainer are you using?
  2. Which resistance setting (if more than one)?
    • You mention ‘Real Road’ which I am guessing is related?
  3. Are you using Virtual Power or a real power meter?

It’s a Minoura MagTurbo. None of the specs detail resistance levels so I have no idea of the watt increments.

There are 8 levels, I have it set on #4; which through trial and error testing, replicates the resistance of actual riding on the road.

Using PM, Stages L-only.

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I have a dumb trainer that is a fluid trainer, and I can do intervals just fine. It usually takes me the warm up efforts to figure out what gears I have to jump up to, and then I can usually drop to the little ring for the valleys and it works out closely enough. The lag time sometimes makes the efforts look like I’m punking out on short bursts, but I know that isn’t the case because I’m in the right gearing and cadence. I’ve done this with VP and a real power meter. The only place I’ve run into trouble is with a magnetic resistance trainer, where you can’t change resistance without effecting the whole power profile and messing up Virtual Power. No problem if you’re using a power meter with a dumb trainer.

I think you are free to increase resistance as needed, because you have a power meter.

Mag trainers tend to have a very linear power resistance curve. As such, increasing the resistance setting should not have a major effect on your overall training.

If you are concerned, you can restrict the use of the “non-real-feel” resistance settings to those particular intervals and/or workouts at the anaerobic levels.

Yup, I know all too well the linear resistance feeling:

I guess all upping the trainer resistance is doing is basically giving me more gears, making my smaller gears bigger, in a sense, without throwing the baseline power profile out of whack too much.

Thanks for the suggestions/answers. I’ve been reading Why upgrade to a smart trainer? to try and convince myself to splurge for some fancy new equipment!

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Hello, I happen to have a dumb trainer also. Mine is the Minoura B60 with 6 resistance levels. Ever since I started my journey here at TR, I’m consistent with my setup (I’m using Virtual Watts btw). Until this morning, out of my curiosity, I tried the hardest resistance level of my trainer. I also did change the setting at the TR app . To my surprise, my sweetspot- threshold zones felt difficult as compared to my usual setup. I can maintain perfectly my power zones on my usual setup, but in this new setup, it really felt difficult maintaining my SS and threshold zones. Is this normal?

For a virtual power setup, you need to test and work at the same setting. Don’t assume they will all work out if you swap after testing. Too many variables to trust changing any one of the in VP.

If you want to change your resistance setting, I strongly suggest a fresh Ramp test.

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So maybe I’ll just stick with the resistance level I used to train with. :sweat_smile: Will I not miss out anything if I stick unto my usual setup?

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Unless you were riding hard enough to run out of resistance, there is no need to change.

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Can you trust power numbers if you back the resistance off one fifth of a turn?

How does marginally lower trainer resistance impact power numbers?

  • Maybe, because he has a power meter and was presumably using that instead of Virtual Power. But he also mentioned that he did not calibrate it since a ride outside (days earlier) so I have question the validity from that oversight.
  • Not at all, assuming real power and not VP (as above). A looser roller tension will still apply resistance (assuming no slip) and it will simply spin faster to hit the desired resistance level. As he’s using a Kinetic Road Machine, there’s little chance that reducing the tension one turn will lead to any negative impact.
  • The most likely difference is that it will likely spin faster, and benefit from more flywheel inertia. This is a hack that I hadn’t considered for users of dumb trainers. But it may well be a way for them to tweak the rear wheel speed (and related trainer speed) to get different levels of flywheel inertia and still hit desired power targets. This whole concept absolutely relies on using a real power meter and not Virtual Power, but it may well achieve the goal.
  • In this case, it would be very interesting to see the speed of the wheel during the best 1-minute power from this test and a similar one at the prior roller tension. If it is spinning at a different speed, it may prove the point about the flywheel inertia adjustment for this trainer at least.

Hi Chad, I’m on a kk road machine + powermeter and sometimes worry my cadence might be too high (example: did 20 min ss intervals at 92% ftp with average cadence of 104)

I’m using my small chainring because I live in an apartment and don’t want to make too much noise out of respect for my neighbors.
Would increasing the resistance of the trainer allow me to stay in my small chainring by lowering my cadence a bit?
I’m also asking because if my ftp will increase, I reckon my cadence will have to go up as well. Been struggling with this thought for a while.

(50-34 front and 11-25 back, and using 14 in the back for the ss session I mentioned. Could go to 13 but wouldn’t that mean I’m cross chaining?Hope you don’t mind my long question)

  • With the KK Road Machine the only “normal” way to increase resistance is by spinning the resistance unit faster.
  • That means spinning a faster cadence in the same gear OR spinning the same cadence in a faster gear by shifting up.
  • It might be close to the limit and not desired.
  • You might try 50 / 19 = 2.63
  • That is close to 34 / 13 = 2.62
  • So that would be a similar ratio for noise control, and might be a better chainline.

Back the the resistance question above. There might be a way to do it and keep the trainer speed lower. You can use strong neodymium magnets set close to the aluminum flywheel. They created eddy currents that slow the system down. I added a resistance bar (with 5 large magnets) to my aluminum rollers, and it really makes a difference. The trick would be how to attach them, but we could work on some ways to do it if you want to give it a shot.

I tried the 50/19 ratio and you’re right, the noise isn’t much different. Thank you for the tip! Much appreciated.

(The workout did feel easier though and I upped the difficulty for the last few intervals. Should I retest ftp in big chainring?)

Won’t likely make much difference in gearing. Since you are effectively in Resistance mode only, the assuming the same drive ratio and final rear wheel speed, the only difference between large and small ring is finite. The difference in chain bend is more on small, but the difference is likely a watt or less different. Nothing to sweat.

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