100

The Theory of Oval Chain Rings | ROTOR Factory Tour


(whooshing) – We’re here at the Rotor
HQ and factory in Madrid to find out how Q Rings are made, the science behind them, and
then to go for a ride on them. And I’m really excited,
some of my best results were in Q Rings and it’s been a while
since I last used them and I can’t wait to find out more about the changes that have
been made in those recent years. Rotor are famed for their manufacturing of aluminum components. They are also known for their production of elliptically shaped chain
rings, known as Q Rings. The theory behind Q rings
is pedaling efficiency. The idea is to reduce your gearing whilst in the dead spot
of your pedal revolution to help accelerate you through this point. The gearing then increases at
the point within each stroke where you can produce the
maximum force on the pedals. The idea is to create a more effective and efficient power output. So Pablo, these have
been years in the making. It’s not happened overnight. Could you talk me through the theory that goes into a Rotor Q Ring? – [Pablo] The idea was you
push with one leg going slower and the other one, in the
pulling phase, was going faster trying to imitate the arms of a swimmer. Then it was really good for the knees but the biomechanics, let’s
say in the pushing phase, was similar to this. Then we stopped this concept in 2005 and then getting the most of that product, talking about biomechanics,
we put everything in our single oval ring which
at the end is just a ring. Of course at the very beginning, to adjust the gyrator was a bit
tricky but at the end weight was not compromised,
price was not compromised, and then was much more easy to succeed. – How long does a ring last? How many kilometers do you think? – Much. – Yeah (laughs) – When I go to, imagine
Carlos Sastre Grandfondo. – Yeah. – And then I go there in Avilla, and now you realize how many people are
using 2008, 9, 10 rings and still they use the same. As if it’s not possible
to keep on selling. – So something that strikes
me as key to your success with development of the
Q Rings is how closely you work with some of the
top pros over the years. World time trial champions,
Tour de France champions, well the list goes on. Olympics. You’ve won everything basically. How has that helped with
development of the rings? – I think we put a lot of
effort and a lot of love in following the riders to convince them we are going to support
them as much as possible. Making tests, tests with the (mumbles), at that time it was like (mumbles) with these kind of tools. But as we’re all following
them in the car, making shifts the same day, different
bikes, different OCP’s trying to adjust the ovalisation, looking for what to
use for the time trail, what to use for the climbing,
as well, eve, for example Manila vosch, at the very beginning was, she was using different
orientation for the ice, for the very frozen
races in the cycle close. And then, being so close to the riders, we realized the success was coming. We had really, really good results. (dramatic piano music) – Before we get access to the factory, Rotor, and the Rotorians, insisted we join them on their lunch ride. A key event of daily life at Rotor. (brooding music) Though I do have a hunch this isn’t their daily route, you can argue that it does offer stunning scenery. I’ve interrupted the
Rotor lunch group ride to bring you a bit of
a rundown of the bike they’ve built up especially for me. Now, it isn’t my own Canyon Aeroad, but it is very similar. It’s the same size frame, but it’s in this monochrome color which I think really sets off against the ROTOR 1×13 Groupset. So, with that groupset, I have a 39-10 cassette that back, with a 46 tooth Q Ring, which I’m now running in position three. I’ve got my 170 mil, two in
one power cranks on there, which is really cool, because
I get to see the balance. I’m running my own pedals, of course, and he groupset comes
complete with Rotor’s own R-45 wheels, with our GP
5000 tires on top of them. And then Rotor teamed up with Magura to create their disc brakes. All in all, it’s the first time I’ve ever ridden a hydraulic groupset. And look at the views. What a place to test it out. (rhythmic music) So, the Rotorians, as they are affectionately know by Rotor, have been explaining why midday ride is so important to them. It’s not just the chance to out of their office work environment, but, it’s a great time to product test. So something that they’ve
created that morning, can literally be tested that afternoon. But also, it’s great for
creative freedom of thought. The guys say they go back to work with a renewed enthusiasm every afternoon. And the afternoon passes by much faster, and they get a lot more
work done because of it. The ride culminated with lunch, before we headed to the factory. And I was particularly interested to follow the journey of a Q Ring. From sheet metal,
through to final product. (upbeat music) You can probably tell, I am now inside of the
first part of the factory here at Rotor. And I’ve stood next to a
giant sheet of 7075 aluminum, which will form all of their chain rings. Both round and Q Rings. Now, for that to happen, these giant sheets first have to be lifted
into this machine here. This is the MACH2. It’s called the MACH2 because
of the speed of the water jet that cuts the sheet. The speed of the water is
two times the speed of sound. So it’s incredibly fast, and can cut incredibly thick material. Now, round rings are formed
out of these giant cookies. And this is not something I’ve made up, that’s what Rotor call them officially, and the Q Rings are made
out of these squares. That’s to minimize wastage when they code to form the chain ring. It takes about two minutes to cut one of these forms. Which is incredibly fast. And when you consider that on a single piece
of sheet of 7075 aluminum you can form up to sixty different rings. And it takes around two hours, unmanned, this machine
just gets on with it and pumps them out. The sand that’s used to cut the material is then drained and bagged, and
reused in building material. So there’s no wastage there. And the sheets are lifted
out and recycled, as well. (upbeat music) Step two of the process happens in the DMC 65 H duoBlock milling machine. My square sheet of aluminum
enters the machine here, into a bespoke mount. This machine manufactures
two rings simultaneously. As the rings are not symmetrical, they produce each side individually. First, side A, followed by side B. This effectively doubles the speed, and therefore the capacity, of the manufacturing process. Now, I mentioned to you a second ago about side A and B on the Q Ring. Side A, the external
face of your chain ring. And side B. These are processed individually, but at the same time, to cut down on manufacturing time. Now, my square sheet metal no longer looks like a
piece of square sheet metal. It now, really is, an Aeroad Q Ring. And I find that quite exciting. We have a brief quality control here, to check that there are no rough edges left on the chain ring. And also to check that the teeth
are of the correct profile, height, depth, and width. And then finally worth mentioning, is the waste material that’s left over. Now, apparently, only around
20% of the total material that comes into the factory, is actually used in the final product. And the rest is recycled. There is zero waste from
manufacturing a chain ring. (upbeat music) Now, my chain ring is
fresh out of the machine and I’ve brought it over to the final step before it’s sent away for anodizing, they’re sending them away
in big batches every Friday. And every Friday they come
back in fully anodized. And I find this truly fascinating, every single Rotor chain ring ever made is engraved by this machine, here, with how many teeth it has on it. (upbeat music) Now Rotor are perhaps best known for their anodized black products. And it’s at this point, where
everything is shipped off in the departure lounge. The cranks will come back
anodized next Friday, after they’re shipped off this Friday. And the same for these chain rings. And, just like magic, here are two that came back this week. So now I’ve found out
how Q Rings are made, it’s time go and find out
the science behind them, and how to put that into
practice on the bike. So we’re back upstairs at Rotor HQ. I’m now on my bike, and I’m about to be put through my paces by Irene. With three tests to help establish the optimum chaining position for me. But first, could you please
talk us through what is OCP, and what is OCA, and what
tests am I about to do? – Not every person rides in the same way. And we all apply our
maximum and minimum forces at different angles of the pedal stroke. So it’s very important that we
can orientate the oval ring, so we find the maximum resistance in the angle in which we are
applying the maximum force, and the minimum resistance in the angle in which we
are not able to apply, or in which we are
applying the less force. Because of this, we developed the OCA, the optimum chaining angle metric that shows which is the body
center of your pedal stroke. And that is directly related to the OCP. – And these are the same tests that you do with your pro teams that
are supply with Rotor? – [Irene] Yes, exactly. – And then how will we
get the results from this? – So, I’m going to record
the data with the phone, which records, not only power and cadence, but also the OCA and OCP metrics. OCA is the optimum chaining angle, and it has a direct
relationship with the OCP, which are the different positions in which we can position the oval ring in relation to the crank ham. – Yep, okay. So, years ago, when I did use Q Rings, I ran them on setting two, and this is based on feel and
advise from other team mates, that sort of thing. I’m quite curious to see if that’s what I should’ve
been using or not. (upbeat music) – You can already look
at the numbers here. – Okay. – This is the first interval. And average power of 311, and the OCP was position four. This is the second interval. 380. And it’s again the same, like this OCP, OCP four. – So it’s consistent, so far. – Yes. And the same thing for the last one. 460 watts in average, and OCP 4 again. – Okay. So what were the results of my test? Well, setting 3.5. That is very precise, yes. And quite different to position two, which is what I raced on
years ago out on the road. Rotor do say the indoor trainer will often slightly misquote this
outcome by up to one point in their OCP. So for me, that would mean
reducing the position down to position three, when out on the road. – There is no wrong or right. If you feel good with, even if this says position
three for you, let’s say, if you use position two,
because you feel better, that’s completely fine. So– – Because we are talking
about fractions of a degree. – [Irene] Yeah, just a few degrees. So– – It’s a good guide. – [Irene] Yeah, exactly. – Okay, right. So whilst I’m warming down, and I’ve got you here Irene, I’d like to ask you a few
questions about power meters. So you develop Q Rings first, here, but then you quickly develop power meters, not long afterwards. What was the reason for
doing them together? – We wanted to have a tool, like a scientific tool, that allowed us to give
an advise to the rider, which OCP position is
the best for everybody. So with the power meter, we can have that. We can give our tool to the rider, to know which is the
best position for them to take the most advantage
of the oval rings. And it is not only about the position, it is also about pedaling style, and to know better himself, to know what his pedal stroke is like. – Okay. So that leads me
on to my next question, which is, when elliptical chain
rings first became popular, around 10 or 12 years ago, now, there was a lot of talk
about how power meters where unable to cope with the
numbers they were producing, because, is it the
inertia of the power meter was no longer consistent, the crank needs power meter
throughout the pedal stroke. So how do you avoid that? – [Irene] So, what we are
doing with our power meters, is to measure a cadence is not once per revolution, but more than once per revolution. So we can compensate for
those changes in speed along the pedal rotation. – Okay, so one big thing I’ve
noticed over recent years, is that power meters are much more stable than they used to be. They used to fluctuate with
temperature much more often, and you just had to be really strict with doing a zero offset. Either before every ride or whatever. But I’ve noticed in your
instruction booklet, it says actually as long
as you don’t change pedals, or change the cranks from bike to bike, you only need to do it every 30 hours. So what’s the reason for that becoming more stable than it used to be? – [Irene] Every power
meter works different, and like changes with temperature, depending on how the strength
gauges are positioned in the power meter. And it also depends on if it’s
an axle based power meter, or a crank based power meter,
or a spider based power meter. Because we are measuring
in the Twin Power. For example, that you are riding now, because we are measuring in
the axle and the crank ham, because of the way we
put the strain gauges. They are automatically compensating those temperature changes. And that’s why we only
recommend to do the zero offset when you install the cranks in your bike, and then after thte first 30 hours. Because, you know, when you first install, then everything has to get in place. So after 30 hours you
should calibrate again. But, for example, with the
spider based power meter, the INspider that we just
launched in Eurobike, we had to do the temperature compensation. So, we do test, like from minus 20 degrees, to plus 80 degrees. And we have like an algorithm that compensates for
that temperature changes. – So what is it about
the Rotor Twin Power, that sets it apart from your
spider based power meter, or other power meters on the market? What’s different about his one, to those? – For us, the very special
thing of our power meters is, first of all, they are
compatible with oval rings, not only with Rotor oval rings, but with other oval rings in the market. Like in terms of not
over estimating power, because they assume the average, like the speed in the
pedal rotation is constant. The same way I said before. So, you can use them with oval rings, and then still have an
accurate power measurement. Then it’s also very
important for us to have this recommendation of the OCP position, on which you should use the Q Rings. Then we have three different power meters. And they are all different, depending on if it’s INpower, INspider, or Twin Power. So the INpower only measures left leg, and then multiplies by two. Then the INSpider sits in between, because it measures combined power for the two legs at the same time. But it doesn’t differentiate
between left and right. It gives a balanced number, but it is not like a real balanced number, it’s more of an estimate. Yes. And the Twin Power is the most
cpmplete power meter we have because we measure left
and right, independently. It’s like having two power meters in one. You have the strength gauges, and the axle that measures the left side, and the strength gauges
in the right crank ham that measures the right side. – I’ve had a really insightful
and amazing couple of days here with Rotor. I’ve learnt a huge about from them. Especially learning about what goes into the process of
creating their products. If you enjoyed this video, or you learnt something from it, please do give it a big thumbs up. And if you want to check
out another video right now, click just there.

Yvette Parker

100 Comments

  1. Interesting – lots of facts..the c.set looks nice tho it'd be another outlay… ;/

  2. Terrible statement from GCN "let's see the science behind them" it would be more correct to state let's see the marketing tools behind them as there has never been convincing large scale research that has ever proven the benefits of oval chainrings. It could be placebo but you fail to clarify this in your infomercial

  3. This assumes the hamstrings don't work on the upstroke. Wrong. Why would you only use half your muscles?

  4. isn't this just the same as biopace we had in the late 80s early 90s. this is just a revamp of a product that didn't work then. just for the young fashionable people who want something new. just saying.

  5. Track riders , better cadence and speed but will never be able to use Q Rings . 🤔 what’s the point .?

  6. after the lunch ride you never spoke about the handling, gearing, hydro, and oval chainring feel…. ie: how you liked the bike?

  7. I picked up a set of O rings in 2008-09, got used to them and loved them. My problem was they weren't available for the 2 other bikes I was also regularly using and going back and forth was awkward. I haven't used them in years now but can see a day soon (reason for a new bike?) when I can get a one-by like that Canyon that I can use a range of tires with and only pay for one chainring. Perfect for that really because oval rings can cause front shifting problems.

  8. I have them on one of my bikes, I can't tell the difference. They may be good for Chris Froome, but they're the kings new clothes for us mere mortals. but I would never admit to that…

  9. Noticed that one of those Rotor guys was handily mixing it up in the sprint with an ex-pro too. Pretty handy office sprinter! Maybe they lunchtime ride to power everyday!

  10. notice the little text at the top right of the thumbnail that says "ad"? that's why there's no real exploration of any cons that may exist with the product .

  11. #Torqueback How does riding on the flat compared to climbing affect the position of the Q Ring? Isn't power applied differently in the pedal strokes when climbing?

  12. I've used Q-rings consistently since 2006 — I obviously prefer them, but have always wondered if it is more placebo effect or an actual benefit (and I use a PowerTap hub, so my watts measurement is not affected by the variance in cadence)

  13. Please, please, please can GCN or ANYONE just knock on the door of a physics or engineering professor and get an answer on these things. Where are the forces acting? What would an extreme elliptic feel like? What happens of you put an elliptic on 90 degrees rotated from where it should be.
    Stop talking to manufacturers, for God’s sake. It’s like asking CeramicSpeed I’d they have any innovations in drivetrain technology 😜😜😜

  14. I had a Shimano Biopace (oval chainring 1990s) on my mountain bike and I loved it. Nothing new here.

  15. If round chainrings are good enough for Peter Sagan they're good enough for me.

  16. Can all future videos dealing with the subject of oval rings either 1, have a picture showing Biopace it is not 2, start off with the 5 seconds needed to say "no it's not that for petes sake let's have one discussion where 50% of the comments don't mention it, it is not the same thing"
    Or 3, add the word to the naughty list please. 🙄

  17. I didn't see any theory? Got any theoretical basis to an optimal shape or any experimental data?

  18. You need to dial into Mr Adam Hansen, he'll tell you a few things about Oval Chain Rings.

  19. Currently building up a bike with my first oval chainring, but from Absolute Black. Tho I'm waiting on a Rotor 12 speed cassette that's backordered :^(

  20. I'm curious how hydroforming would affect a [sub-]human body. Better yet, would the water pressure suffice to, say, carve inbreeding out of animal abusers', such as hunters' & butchers', smooth brains – and raise their IQs beyond their single-digit range? I'd damn sure like to try.

  21. Rotor makes quality chain rings, I've been beating the hell out of my current set for roughly 5 years and they're barely worn.

  22. Really?!?!?!?!? Me thinks the video needs a trip to the editors. (3:55) "Though I do have a hunch this isn't their daily route, you can't argue that it does offer stunning scenery." Perhaps the scenery should have been in focus and not the rider.

  23. I own a few rotor parts, cranks, spiders and bb’s. I would certainly NOT recommend anything made by rotor. Product quality has been spotty and product support is nonexistent.

  24. Chris asked such good questions during that interview 👌👌, excellent info my man. Felling an itch in my wallet now 😬😬

  25. If the uci mandates the width and breadth of tubes by ratio how does that same governing body allow anything other than a round chainring ?
    I’m older so I’ve ridden suntour ovals and shimano biopace
    Even in my prime (‘90’s) there was no advantage over round across a mixed bag of conditions
    Maybe if I had been better I would have noticed

  26. Older cyclists what is the difference between this(Rotor) and Shimano Bio-pace in the late 80's?

  27. Is this different from Biopace in the 80s? The patents ran out? Kinda like Apple creating the Mac from Xerox parc 60s tech? I'm still with theory that what ever power you can extract from rider is what you get, no matter the way. It's physics 101. Love to know more about what I am missing here.

  28. How about a video on the Theory of Oval Chain Rings? This video explains nothing. I still dont understand how the shape makes a difference.

  29. In the 80s my dad bought a 'mtb' from Halfords (apollo Vesuvius) with a suntour ovaltech chainring set. It still is going and is a pleasant bike to ride

  30. Good Review. I started with a lot of skepticism but this is actually a lot more interesting than I expected.

  31. These rings are great…as long as you never need to switch from small to big chainring, and you never get out of the saddle. Otherwise you’re dropping chains and falling over. And even if these rarely happen, once is enough to make you never want to get on that bike again. Thumbs down from someone who tried.

  32. English subtitles please for the Rotor representative at the start! And I have lived in a Spanish speaking area for 25 years so I should be used to the mess the Spaniards make of the English language when they try to speak it. Even after listening 3 times I still can't get everything he says!

  33. My old technical drawing teacher invented the elliptic crank but the idea was stolen from him and i left school in 1983. He was a prick anyway but he got his pants pulled over his head.

  34. I hate how is listening and talking like trinking a coffee while putting out 350W 🙂

  35. In theory, oval chainrings offer a negligible benefit. In practice they are just incredibly ugly.

  36. so I understand that the concept is maximum resistance with maximal force and minimal resistance with minimal force but how did they settle on the 12.5% ovality that they use why was 12.5% better than 10% or 20% ovality

  37. So is it a theory or not? If q rings are better why don't all pros use them? And why don't bikes come with them?

  38. I wonder to what degree, if any, the advantage of the eccentric chainring is negated by the two oscillations of the chain tensioner with each turn of the pedals (losses due to friction in chain tensioner bearings as it swivels back and forth, and heat dissipated by its spring, and the chain itself bobbing up and down).

  39. No need to get all excited about the recycling they do.
    Every single manufacturer who works with metal has been doing that for ever.

  40. Another good video, work horse, record holder, great presenter? cant tell yet but is learning fast about it …
    … Irene barely blink looking at him.
    …is it me or was it a little sponsored/ paid promo for rotor. just saying. anyways was very informative.

  41. My custom made 72T oval chainrings https://www.youtube.com/watch?v=Wk9vlsHMzYI are laser cut in stainless steel within less than 1 minute 😉

  42. Nice to see biopace making a comeback. I still have some on some of my bikes. As always, cycling trends going around in circles.

  43. Whats the actual theory or efficiency gains from using these chain rings though? Still not sure after watching the video…

  44. Shimano had these on mountain bike in the late '80s. There is nothing new to see here. If it worked it wouldn't have disappeared in the '90s.

  45. If they actually worked as advertised, every pro cycler woud be using them….good improvements like narrow/wide chainrings actually have a noticable improvement, I am not convinced this is an improvement. Pedal bikes are one of the most refined inventions, and is difficult to find any sizeable, measureable improvements to design. Lighter components and materials have helped recently…..but the mechanics of cycling still remains much the same after 100 years. Goes to show how great of an invention a bicycle was!

  46. As the title of this vid is 'The Theory of Oval Chain Rings', I thought it might be about the theory of oval chain rings. However after watching this I've discovered that there was nothing about the theory of oval chain rings, so I still don't understand the theory of oval chain rings.

  47. I'd love to see GCN (or GCN Tech) do a comparison of Q Rings alongside Shimano Biopace and Ossymetric rings to see what difference there really is in the pedal stroke. Are they all the same idea, or are there significant differences?

  48. Hmm, I have some Shimano biopace chainrings on old MTB that I bought in '90 or '91. What's different?

  49. Great video!! Putting force into the crank arm is nothing like a freestyle swimmers stroke, I don't get the analogy. My main issue with oval chain rings is how many watts are lost through the rear derailleurs constant movement during the rotation V watts gained by mechanical advantage? I have always doubted that the theoretical isn't equal to the reality. anyway they look cool and that counts!

  50. Not a new idea, had these in late 80s, if you don't mind blowing out your knee's, there great

  51. I reckon that with oval chain rings and L-shaped crank arms, I should be taking all my local KOMs next year. Thank you for bringing this to my attention.

  52. Huh? Did i miss something here. My wife had a Shimano groupoon on her Pinnarello in the early 90's with oval chainrings! I. E. this is not new. It may be different in a way… but the concept was there back then. She got as lot of flack and derision from "purists" about them

  53. What is hard to understand here? Moving chainring back at downward stroke rotation increases leverage and thus torque. It’s like longer crank effect without longer crank.

  54. I'm wondering if the rider can feel the difference in
    his pedal stroke. Harder to pedal? Easier? or no change?

  55. 9:30 – will an oval chainring make me able to push 500 watts whilst casually chatting away like I'm on a coffee ride??

  56. 1st pioneered by Rotor? LMAO. My 92 road bike had Bio Pace chain rings. A name change doesn't make it new.

  57. A special thanks to GCN. I watched the video and sent an email Rotor about the possibility of going for a lunch time ride with them and they said YES. I am from New Zealand and on holiday in Spain for a holiday. This is a fantastic opportunity. I will let you know how get on. Thank you GCN!!!

  58. Does the chain tension change? I'd like to use one on my single speed cross bike.

  59. Really enjoyed this Vid. Thanks to ROTOR. insightful questions . Good information shared. Not a massive GCN fan , but I do enjoy Chris. Perhaps he goes a little deeper. Anyway . Well done and thanks

  60. Not sure about all of the negativity in the comments here and the "lack of science" comments. It's a big subject and to cover all of the information that different individuals might require would take a much longer and in-depth video than this one. I can only provide my experience with ROTOR products, with a little bit of what you might loosely call "SCIENCE". I run ROTOR 2in1 175mm cranks and BB on Specialized Epic MTB with a 32 or 34 (rare) tooth Q Ring in a 1×12 SRAM AXS setup. I race XC media(half +/- 50km) marathon and marathon (+/- 100km) as well as multi-day races (just completed the five day Roc Trophy at the Roc D'Azur in Fréjus France 232km). The products have been flawless. There is no excessive wear to either the Q Ring, the cassette the derailleur, jockey wheels, chain, clutch etc in any conditions. When I started with the products I used the app more frequently. There are two options, App on the phone or full software on the computer. The software on the computer is more in depth and is intended for indoor situations with your bike in a trainer or on rollers, where you (or your coach/ trainer) can see the readout in real time of your pedal stroke and metrics (torque, efficiency, balance through the pedals% etc). I have always used the App, as I don't put the full suspension MTB in the trainer. The App allows you to do various things, even just to record a ride (and in the latest version, this uploads directly to Training Peaks/ Strava etc, useful with Strava's latest actions). The more important (for me) has been the "Torque 360" element of the app, which is where OCA and OCP come in. I started on position 3 (as recommended). After undertaking the sessions as directed, the software determined that I should have the Q Ring in position 4, easily changed. The Q Ring allows for a smoother pedal stroke and less time in the "dead zone" coming over the top of the pedal stroke. This translates into a smoother pedalling style, especially when climbing. When grip is at a premium, or the going is rough, this has allowed me to maintain a smooth output and drop riders who are struggling to climb and find grip. It might be "easier on the knees" but I didn't have knee pain before and I don't have it now, so I can't comment. It takes about 10 hours riding to adapt to the Q Ring(s). This year I have been using "The Sufferfest" and the training program I have been following has improved my fast twitch muscles and their engagement and usage (175mm cranks = long pins). After completing the program and feeling like I had made gains and benefits, I went back to the ROTOR App and ran the Torque 360 again, lo and behold I am now recommended position 3, meaning my legs are firing earlier in the pedal stroke and releasing my max output sooner. I think that's SCIENCE isn't it? 😂 The ROTOR 2in1 system communicates perfectly with my Elemnt Bolt, providing all power and cadence metrics and allows me to have all of the metrics (and more) at my disposal in front of me. I have one screen showing all of my pedalling metrics for those days when I am concentrated on maintaining or making improvements in my pedal stroke. My experience has been only been positive, with the product hardware, the usage, the customer support and what I feel are benefits to my training, racing and power output. I can't say any more than that, or be any more "SCIENTIFIC" 😉

  61. Very interesting. I had a special Trek touring bike back in the eighties with an elliptical chain ring. It didn't work for me as I had decades of circular rings. I was amazed to see Froomie riding one. Back in the criterium days, it was spin to win. I saw Armstrong do it in his day and Froomie doing it now. Amazing the tech involved with cycling today.

Leave a Reply

Your email address will not be published. Required fields are marked *