L/R pedaling imbalance

I’m seeing a disturbing trend in my cycling, where my L/R imbalance is increasing. I used to average 53/47 but it’s been getting even more pronounced over the fall, to where I’m now at 55/45 as my fitness has decreased with a lower training load.

I had a Trek bike fit in January and bought a new bike at that time which fits me correctly. I’m not sure how to go about improving that imbalance, looking for some advice to help.

Also, EOS is just frustrating to me. Pedaling in squares, circles, scraping mud just don’t work as analogies for me. I can’t figure out what those motions are supposed to feel like.

Here is my weekend ride showing my cycling dynamics averages.

I saw a strange shift in my L/R balance once and it was simply due to my saddle, therefore sitting position, not being quite straight. Just saying because it was an easy fix for me.

p.s. have to say I’m not a fan of EoS. My easy fix for that one = don’t do it :slight_smile:

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A few things… hopefully this helps - as mentioned it might be sitting position. It may also be that the bike is not quite vertical… may be worth a check with a spirit level.

I noticed something similar and raised it with my osteopath, he asked if I was left or right handed and explained the less dominant side is less able to fine tune effort, so ends up a little more on/off than the other side which is better at grading effort.

Made sense because in harder efforts I saw the imbalance fall away to 50/50. I use a rocker plate now to provide a more varied and natural riding feel, I would not want to ride the turbo without anymore and it seems to have helped with the lower effort LR balance.

I am left handed, that might account for some of the differences. But the imbalance is worsening with no changes to my setup. That’s got me a bit concerned.

Hi there,

from what i’ve read about the topic of leg imbalance and pedal stroke (sorry i don’t remember sources) typically when you start to loose fitness the imbalance may increase because your naturally dominant muscles will take over more of the load. Hence when you improve your fitness and do some focused training to even out the strength both sides,will help to correct the unbalance, however you don’t necessarily have to reach a 50/50!
Also, I know the more we have metrics the more stuff we want to control and improve, but also some studies with professional cyclist have demonstrated that focusing on improving pedal stroke e.g to make more circular efforts actually didn’t really improve their performance.

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Hello @Sir_Brian_M! Generally speaking with L/R balance, I always start with saying that depending on the kind of tool that you are using to measure L/R balance the values that you are seeing may or may not be real. So, if you’re using L/R pedals or a Powermeter with a separate strain gauge on each side of the crank then you likely have true L/R readings. That being said, a difference in battery level from one side to the other has also been known to affect some L/R power meters so make sure your batteries on both sides are new! As was mentioned previously, making sure that your indoor setup is completely level is also an important thing to asses with a level to be sure. Also, we always see that the lower the power output, the bigger the difference in L/R power. Once folks get up to around FTP and above, then we typically see an evening out of power output…so if you’re doing lower intensity training, you’ll tend to see bigger differences in L/R power than you would if you were performing more intense training. One thing that can be useful in seeing how differently you might be pedaling from one side to another while indoors on the trainer is to unclip one foot at a time with a target power of about 40-50% FTP and pedals for 20-30 seconds with one leg (other foot unclipped), then 20-30 seconds with both, then 20-30 seconds with just the other leg (opposite unclipped) and repeat this a few times. This will often highlight any significant differences between one side and the other. During the in between single leg efforts while your pedaling with both legs you can think about trying to smooth things out and pedal more evenly as a drill. Hope that helps!


Thanks for the input Sir Neal. Always a pleasure to receive your advice ! My L/R source are Vector 3 dual power pedals. And the ride in question was outdoors. I’ll ride EOS tonight and see if I can narrow this down a bit.

NOTE: G (not Gerraint :stuck_out_tongue_winking_eye: ) recommends replacing all of the batteries at the same time. Do not mix the battery types.


I gave my steed a thorough examination last night: 1.The saddle was skewed slightly to the right side
2. The bike was also leaning slightly to the left on the trainer.

I corrected those and rode EOS at reduced intensity. The power imbalance was still 55/45 and other metrics showing a less efficient pedal stroke on the right side.

So I began suspecting that my saddle height was not optimal. It seems like my saddle may have been a bit too high since I noticed my hips rocking a bit. I was dropping my pelvis on the left side, causing a more pronounced imbalance.

With a lower saddle, I’m feeling more connected at BDC and my L/R imbalance seems closer to normal. I’ll need a bit more time to see if it’s truly improved, but I’m hopeful that I can at least make progress.


Remember also, whenever you change the bike fit, leave it some time to adjust, and saddle height no more than a couple mm at once! or at least that was what the bike fitter recommended so that the body adapts and also for you to know which change affects what.

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That’s perfect - assessing the possible variables, making some changes, and evaluating the response. Love it @Sir_Brian_M!