O ROTOR, ROTOR! wherefore were thou ROTOR?


We all love a misquote.

This post is nothing to do with Shakespeare of course. I often hark back to the memories of one of my few, fleeting misses of sporting success to wonder if ‘piece of kit X’ might have made those few seconds difference I needed on the day.

I’ve been using elliptical chainrings on my TT bike since 2013. I reckon they make a difference and so do Froome, Wiggins and others.

By agreeing with people that are most likely right I increase my chances of being right. Always a good strategy methinks.

As  you can see from the ROTOR Qarbon QRing picture on the right there are a lot of holes to enable changes to the position of the maximum part of the ellipse in relation to your pedalling action.

The ROTOR manual says something like, use position 3/5 and ride with it for a bit. then fiddle about with the other positions and see which is best. Not a great strategy IMO.

Anyway ROTOR have finally nailed this. I’ve been playing with one of their 3D power meters which is inside the crank spindle/axle. More specifically this comes with ROTOR software that can determine at which part of the pedal stroke you exert most force and then deduce from that what the best position is for the QRing.

I did that last night and the results were incontrovertible and quick to appear.

Regardless of my power output or cadence I was a borderline position 4/5, erring towards position 5.

When out of the seat I needed position 6…which doesn’t exist. this probably explains why I stay in the seat going up hills.

Here is one screenshot – quite hard to reach to press the printscreen button when pedalling but it’s illustrative enough for these purposes.


The green line shows the Optimum Chainring Angle (OCA, 98.26 degrees). I’ll also draw your attention to the 454w on the left hand side, just because it looks good. Those who know me will cite 468 as my maximum 5s power output, maybe 🙂

The software then translates the OCA into the Optimum Chainring Position (OCP), which you will see highlighted to the top right hand corner.

It really was that simple and definitive.

The caveat would be that this was on my road bike which I never feel that comfortable on. Maybe it might not translate to my TT bike where, tbh, I always use  the QRings.

So reverting back to the intro to this post. It’s clear I’ve been using the ROTOR Qrings incorrectly and I would see also say it is  clear that, in the right position, I would produce more power and/or be more efficient.

The fleeting moment of near success that I also referred to was achieved without Qrings. But even if I were using them that day I would have had them configured incorrectly. So I’d say this is another of those ‘at least marginal’ gains that is to be had.

Fortunately for YOU. You can just go and buy some Qrings. They’re something like £40/£50 over and above the price of the chainrings you would otherwise buy. You only need to buy one (big one) and you don’t need the small one by any means. If you’re TT riding then definitely only get the big one.

Unfortunately for you this software that determine OCP only works with the ROTOR power meters AFAIK.  So you want to find a friend with some ROTOR kit to get your OCP sorted out. Maybe some dealers might do such a service? It really would take less than 5 minutes.




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4 thoughts on “O ROTOR, ROTOR! wherefore were thou ROTOR?

  1. To further add that you have to use one of the InPower branded power meters. the original and expensive Rotor Power duel sided unit does not work with the software.. Grrr. On a broader note I am surprised that the whole Power meter market does not allow for this kind of power analysis. I would love for Power Tap to utilise the full data coming from the P1 pedals.

    1. yep. thanks for the heads-up on it just being INpower (2INpower should work…May 2016). I half suspected that but had not checked. I guess you could do a WATTBIKE session and get the peak power angle from POLAR view? Really that’s all I found the software useful for ie just getting that one value…as important as that one value was for me. Garmin’s PP is sort of a measure of that? I suspect that 3D pedalling movements are next on the list to be measured (rotor and 4iiii at least)

  2. I’ve just spent a couple of hours trying to figure out the angles of peak force for each of the OCP positions, and by the looks of things my calcs don’t align with that screenshot you’ve got to offer. Your screenshot suggests (from 1-5) 77, 83.5, 90, 96.5, 103; compared to my calcs 99, 102, 106, 110, 115. Have I read your screenshot correctly?

    1. Hi, this is going back 2 years so I don’t fully remember what I did at the time. I could have used a circular ring to produce the chart above and then reading the chart as saying OCP4 was the one to go for and dialling that in to the ovals. that would seem to make sense in hindsight.

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