Shimano Crank Talk (And Pioneer goes to Shimano)

Pioneer ust announced on their Instagram that they will not be in cycling and cyling equipment including power meters any more.

Shimano is taking over all the cycling related products from Pioneer.


finally shimano might have a working power meter !


Pioneer was no better. This wasn’t a move to acquire any power meter tech. There’s no magic in glueing a strain gauge to the outside of a crank. Everyone has been doing it… all with the same successes (LEFT) and failures (RIGHT).

This is a quick ‘out’ for Pioneer. Nobody was using their head units. Their software was clunky. They relied 100% on Shimano. Shimano at any point could make a slight mod to their cranksets (left and right) to put them out of the game anyway. Same goes for 4iiii and Stages, although both have other crank offerings.

While this news is interesting, it’s not a big deal. The industry is small though… and not much is happening… other than a few amusing updates from IQSquared every few weeks… so this is the ‘biggest’ news in a while.


Always interested in this line of thinking. Just an anecdotal n=1, but my right side Stages Dura Ace has been flawless, so it’s obviously not impossible to pull off.

There is a big difference between getting consistent power reported (my guess on your results), vs getting ACCURATE reported power (what Shane is talking about).

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No, I know exactly what he is talking about. My two Stages L units, Tacx Neo, and R Stages are all within a percent and a half.


It’s data, not a line of thinking. Last count was 15 (or 16… maybe 17… I gave up ‘reviewing’ them) of these cranksets failing my test protocol, all in the same way. While other power meter types/designs pass it. I need power meters I can trust/rely on to test/compare other meters and smart trainers with. None of these can be used for what I need.


I’m not disputing what you found, I’m just saying it’s obviously possible to make them work, mine does with no issues and I know several others who are the same. I’m more curious as to why a lot fail tbh.

Watch the video by Keith Wakeham on it. His name is on the design patent. The guy knows his sh*t, far beyond my level of expertise.

It’s not a case of why some fail. They all do. It just depends to what level they’re tested. Not everyone is doing 50/50 balanced steady-state ERG on them while hooked onto a reliable/accurate trainer along with a pair of trusted power pedals. Riding outside there’s enough randomness for the numbers to almost line up. In a ‘lab’ environment things fall apart. Does that matter? For some people, not at all. For me, absolutely.


This is actually what I was referring to with the line of thinking bit. You obviously can define it how you want for your purposes, but if an item works within its usage profile for its user, it hasn’t “failed”. Outside of that envelope is pretty irrelevant for someone who doesn’t need it. I understand for your purposes it you don’t feel it does but that clearly is a different proposition than it doesn’t work for anyone, which is what is bandied about all the time and I think is a ridiculous assertion.

As I mentioned, I’ve run mine with a L Stages and a Tacx Neo simultaneously and they have all tracked within 1.5%, which is good enough for me. Ray Maker has also had similar experiences while noting some people have issues. But some people aren’t able to get that obviously, which piques my interest.

I’ve seen the video by Keith, certainly informative but it still doesn’t really explain the inconsistency of manufacture.

Keith’s video outlines the issues with measuring power with the right side due to the design, it’s not a manufacturing inconsistency.

I’ll leave it here. If people want to ride these meters, awesome. I can’t.


The argument isn’t about inconsistencies when manufacturing power meters, but that power meters can’t be as accurate with this asymmetric crank arm design. On symmetric crank arms certain forces cancel (or are the same, which means their difference is zero) just by symmetry. Thus, offset and slope of the strain-to-force curve are more accurate on symmetric crank arm designs.

With Shimano’s asymmetric design, these forces do not automatically cancel, and playing with the curve worsens the accuracy of the offset and vice versa.

I think Shimano has its manufacturing down, and whatever tolerances you have can be taken into account during factory calibration — if Shimano had a good design.

The problem is a reminder why power meters will most likely be something that, for the most part, only groupset manufacturers will offer: to get an accurate crank-based power meter, crank design matters a great degree. (I think pedal-based power meters will have their place, too.)

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I have been using Pioneer power meter for 2-3 years and their headset for a year or so and I am quite happy with both.

i think they have a fantastic head unit. If you read the manual carefully, you will find out lots of good training screens. And I believe it has better screen layout than Garmin or Wahoo.

And yes, they have a chunky web site but when you play with it, it basically gives yo allt he information you need, surprisingly in very good way.

But lets see what Shimano will bring.


That’s really weird. The Neo notoriously reports low compared to other power meters. Consitently 15-25w based on the gear compared to my s-works power crank.
Other users have shared a similar experience on another thread with the assiomas and vector pedals.

I’m not going to get into it anymore as it’s not really germane to the thread but to say I’m a mechanical engineer by training (I ended up a yachtie and construction company owner by trade which is a whole different story) and I know the concepts used in strain gauges. Measuring on a asymmetric crank is not an impossibility.

When I talk about manufacturing, my WAG is that the metallurgy variation is probably a significant factor.

Any rate, its a thread for Pioneer being sold, so everyone carry on.

The issue is that the right crank geometry is very far from a straight beam, and thus the deformation-vs-relevant load relationship is both non-linear and load application dependent. The designer ends up making assumptions on the load application, and anything off those assumptions throws the measurements off.

This said, while there is certainly an imprecision in the measure, the real question is how relevant that becomes in real life. Is a +/- 2% power measurement detrimental to training and race performance compared to a +/- 1% measurement? At which point does the lack of precision translate into performance-significant impacts?


My Pioneer L/R (gen 1?) had as many signal drops as my gen 1 Stages. Accuracy was good compared to my Drivo when there’s signal. So much happier with my Assioma Duo.

I’ve said it before. I love my single sided Pioneer PM. Got it brand new two years ago for like $360 and it’s had ZERO issues. I’m not surprised to read this though, Pioneer never seemed to gather a strong following or reputation in the PM world.


Indeed, but this is more a function of inconsistent flexion across units, regardless of the load at the pedal axle (within reasonable parameters, no one is standing on the very edge of the pedal). Aluminum crank arms are the biggest wildcard in this, carbon could be built with much more precise deformation properties.