Completely different L/R balance indoors vs outdoors

So I know that L/R balance doesn’t really mean anything in itself and I would be totally fine if I’d have the same values for indoors and outdoors even if those weren’t 50/50, but in my case I consistently have 46/54 indoors and bang on 50/50 outdoors. This is with the same bike and same powermeter (Garmin Rally SPD 200) on an Kickr Core.
My first thought was that my trainer wasn’t level so I checked and it turned out that it leaned quite a bit to the left. So I balanced it via some cardboard but the balance discrepancy still remains.

Maybe someone has a better idea what might cause this? I already tried different saddle heights, different cleat placement.

Have you considered the lack of motion from a rigid trainer vs the freedom of money outside?

It is one of the most notable differences between the use cases.


I have, but I don’t have the money for a rockerplate.

There are some inexpensive hacks that can be done, some vary with the specific trainer in use. But generally speaking, some blocks of foam can be placed under the trainer feet to allow some motion. Some of the thicker trainer mats are also a decent start.

From a pure comfort perspective, even a slight amount of motion can be an improvement for some riders. It may not help in this case, but if you have some access to foam sheets, blocks, even firm sponges might be worth a quick test.

Rather than start a new thread I thought I’d ask here…I have assioma duo pedals…how/where do I see L/R balance anywhere. Can’t see it on TR, Strava or Garmin Connect?

Just curious about mine more than anything!

From what I know, you need to record with a bike head unit (Garmin, Wahoo, etc.) that actually records the various L/R data. TR does not capture it in any way, so those workouts are not able to review for that purpose.

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IME, L/R Power Balance will vary across a number of factors…indoors vs outdoors, intensity level, fitness, etc.

Personally, I wouldn’t get too concerned about it…there are lots of reasons why sitting on a bike inside is different than outside. Motion, lack of wind resistance, sitting on the bike differently, etc.

Garmin Connect will show L/R balance and your power phase for each side when Assiomas are the power source and you can see that data for any portion of a ride - but as mentioned above, you need to record the ride with your Garmin to have access to that data. Also, if you record on the Garmin, the basic L/R power data will show up in TrainingPeaks. (I assume something similar is available for Wahoo head units too).

So, the short answer is you should get L/R data automatically for out door rides but it takes some work to get it for indoor rides.


@pnzr, @mcneese.chad is being humble. He designed a super inexpensive “rockit plate” and it works great. I’ve been using one essentially since I got my first trainer. I even went on vacation and didn’t bring it, but couldn’t stand being rigidly attached to the floor and threw one together for the week using wood scraps in the garage.


Ha, much appreciated for the props. That cheapy version is the one I used to help kick off the rocker trend.

Since then, we’ve seen a range of more and less complex versions far and wide. That one is not terribly hard or expensive to make, but still goes further than some have for tools and comfort level. I popped into my group to snag just a few pictures of some of the more simple versions. Most of these use “balance pods”, but those can easily be substituted for any of the foam blocks I mentioned. The other common hack is tennis balls, which are easy to access as well. Many ways to make a simple version to at least see of some motion is an improvement.



  • I 100% LOVE this :stuck_out_tongue:

  • I am so used to motion after having it since late 2015, that traveling without a rocker really sucks. It’s one of those things that disappears under you over time, but as soon as it’s missing, I sure notice the locked feel all over again.

  • If I traveled more, I’d make a very small and simple motion setup because it is just so much better for me in use.

My dad’s hobby is wood working so I actually had him build mine. The only thing I did was polyeurethane it to protect it from sweat and chain oil. I even used the foam blocks you recommended in the video. My dad was super impressed (as was I) with the engineering-quality drawings.

The one I built while on vacation was made from a bunch of scrap pieces of wood and old hinges. I ended up cutting 1/3 off of the end of tennis balls for use as the springs. For a week in the Maine woods where I couldn’t safely ride outside it worked perfectly!

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  • Thanks so much!!! I sure hope they are good, because I am a drafter/designer by profession. Being detail oriented and OCD helps too. :stuck_out_tongue:

Great work on the quick hack job too! It’s always great to read comments like yours, where people get back to rigid and notice how wrong it feels. Parallels my experience and reinforces my resolve that at least some motion is better than none in many cases.

Unfortunately I lack the tools and the skill to build a DIY rockerplate :frowning:

Tools maybe, but Chad’s design is simple enough that much skill isn’t needed - as proven by my quick hack in the Maine woods last year. I think you could build one with a few tools as a skill saw, drill, and screw driver.

Of those I only own a screw driver lol

Did you look at the pics I shared. Those ones with just the inflated balance pods under the trainer feet require essentially no skills. Using flat foam block or other compressible material is also dead simple.

If you really want to chase this problem, I think you have to take at least a simple walk down this path. Lack of motion is one of the most impactful differences between inside and outside.

To add another angle, the consideration of trainer feel as a result of the flywheel is also notable. Depending on the trainer in use, gearing used, and your experience outside, this can be a large factor in feel, which may also show in balance. So, have you looked at that angle in any detail?

yea I saw and currently cosindering going down the balance pods or foam route. The foam shouldn’t be too squishy I reckon?

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Depends on how much motion you really want. For foam, it can be fairly soft like you find in those stress reducing standing mats and such. If you really want to promote more of a rocking motion, it is best to have a more rigid support in the middle, that acts like a pivot axis (like the PVC above, or anything like a wood dowel or steel rod). Even those books work.

The key is the stiff middle, and softer side to allow the motion. You really want minimal support on the sides. It’s like training wheels. The less you use them (supports), the more “real” it will feel since you are more responsible for control and balance with less force from the foam and such.

It takes some experimentation to find what you like.

Thanks STP and @mcneese.chad!

Makes sense, I was just looking at my TR rides so that explains it. Anyone know if works with Garmin edge 500 (yes I am that out of date but it works perfectly, has never let me down and does everything I want so why change! :joy:)

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