In terms of the physiological adaptations, there's not going to be a difference between the two. Sometimes on the dumb trainer you'll be under your optimum cadence, sometimes you'll be over. Guess what? Same thing happens on a smart trainer!

I've been using a Computrainer in erg mode for a long time now. It's great for early morning training sessions as all you have to do is "show up and push the pedals". With that said, I'm contemplating training in slope mode or perhaps getting a direct-drive "dumb" trainer. Why? I've spent a lot of time over on the TT UK forums and I've noticed almost none of them train in erg mode. Why? Because pacing is a skill and just like any skill you need to practice it. If you look at some the power files of some of the elite amateurs over there they're crazy flat. Very very very little variability even on hilly courses. We're talking guys doing a 40k TT with an AP of 350w and an NP of 360w.

I recently looked over my power files from last year's races and realized that there was a really strong correlation between bikes that were poorly paced and bad runs. I know that's triathlon 101 but I think over the years I just neglected pacing as a skill and told myself "I glance down at my Garmin periodically so my pacing is fine."

tl;dr in terms of physiological adaptations there won't be any difference, erg let's you just show up and pedal which can be useful to make sure you hit your training targets, and dumb trainers are useful in that they force you to practice pacing.

Smart trainers set the level of resistance not cadence. With a smart trainer you are able to change gearing to adjust the system inertia (flywheel, for most systems, spins faster) and/or change your cadence at will and power stays the same.

For example on my kickr I can set the erg to 300w. The power required from me is 300w for any of the following situations:
-39x28 @ 40rpm (Low cadence, low system inertia)
-39x28 @ 120rpm (high cadence, medium system inertia)
-53x11 @ 40rpm (high cadence, medium system inertia)
-53x11 @ 120rpm (high cadence, high system inertia)

There is no science that trainer type affects training response. Any options you get are anecdotes.

Also, the "feel" and pedal mechanics between dumb trainers is huge. Try riding a cheap mag trainer vs revbox, vs lemond. They couldn't be any more different regarding how they feel. No evidence that any one is better or worse than others.

Try Zwift with the computrainer. Works great.

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--Chris

Thanks for your reply,

So I could ride

300 watts in 53x13 at cadence 95,
and then
300 watts in 53x15 at cadence 95

And the only difference would be the feeling of inertia in the drivetrain... would it be right to assume that if cadence and watts stays the same, and you change gears it would feel like differing gradient? and does wahoo or any of the other trainers recommend a baseline gear ratio?

and if I rode

300 watts in 53x13 at cadence 95
and then
300 watts in 53x13 at cadence 97

then the only difference is the trainer must adjust its resistance maintain it at 300 watts. I am concerned about this element, as this differs from riding on the road where a change in cadence equates to a change in power.

No recommended baseline gear ratio. But keeping your chainline straight is preferable from noise and wear point of view.

So changing gears does make it feel like changing the gradient. Going from big to little ring feels more like climbing. But for the smart and dumb trainers I've ridden, none ever really feel like climbing outdoors. I wouldn't be able to tell the difference on my kickr going from 13 to 15 only.




I disagree here. Changing cadence outdoors only results in change in power if you keep the pedal force constant. Consider your example again with made up (but accurate relative) force numbers:

300 watts in 53x13 at cadence 95 results in the rider applying 10N of force to the pedal.
and then
300 watts in 53x13 at cadence 97 results in the rider applying 9.5N of force to the pedal.


In the example above to keep the power constant while increasing cadence the rider reduces the amount of force applied to the pedal. Power = Cadence x Pedal Force.

This means for your outdoor example:

• you can increase cadence while reducing pedal force to keep the power the same (push faster but easier).
• If you increase your cadence AND power increases then the rider has keep the pedal forces constant or increased them.

Whilst smart trainers have ERG mode which will dictate power, they also have Slope mode, which effectively makes it a dumb trainer. So don't worry that if you go down the smart trainer route you're limiting your options. Quite the opposite.

To me ERG mode is another tool in the tool box. If your session is a sweet spot session, then ERG is perfect. There's nowhere to hide. But sometimes I just want to chill out in Zwift which is a "variable" slope mode and simulates road rdigin, and !go as hard as I want to (which always ends in me going harder than I mean to!)