The jury is apparently still out on Osymetric chainrings and one

could ask whether it’s all just ‘hype’ and another expensive gimmick

that has been thrust in the face of the unsuspecting British ‘tester.’ It

wouldn’t be the first time for outrageous claims to be made about a

‘new’ product.  Who doesn’t remember the PMP ‘L’ shaped cranks

that set the time-trialling world alight in the mid 80s?  If they hadn’t

been used to such good effect by both national champions and

record breakers it would have been easy to be cynical and say they were a con and no better than the standard straight ones … but evidence and extensive research proved otherwise.  ;-)   

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Sir Nob of two Ghiblis of Testing Times fame and himself a lifelong supporter of PMPs (indeed, the author of the world renowned white-paper proving conclusively that ‘L’ shaped cranks were ‘faster’ than straight ones) has come out of the wilderness and his self imposed exile for the benefit of all willing to listen and carried out his own independent tests of Osymetric and Rotor chainrings. This is truly a world exclusive and will blow all the claims being made by the manufacturers and the riders being paid a mint to use them out of the water.



For those of you not ‘in the know’, Sir Nob is regular contributor to Timetrialling Forum. He is a pretty wealthy sort of guy currently living in any one of a number of properties he owns in places where it’s particularly difficult for HM Customs and Excise to get hold of him.  He’s the sort of person who doesn’t believe in a lot of the meaningless hype put out by manufacturers of cycling products and since he’s got lots of money and loads of spare time on his hands is committed to dispelling myths … if indeed that’s what they are. So to finally ‘clear the air’ with regard to weirdly shaped chainrings he has fitted sets to two of his bikes and covered a number of kilometers in variable conditions meticulously logging results as he went. So for your eyes only, this is what Sir Nob has to say …



His findings …

Osymetric Rings

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For the purpose of my tests I fitted the standard rings (Campag) 54/44 in black. 

Although they can also be obtained in silver, I fitted black because black ones are

faster (conclusively proven in previous tests of mine).

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Installing the rings on the spider was a struggle in itself as the BCD holes did not

appear to be properly aligned (so already not a good sign!). I would therefore highly

recommend carefully checking the alignment before purchase. After fitting them, it

very quickly became apparent to me that they were not sitting flush with the spider and,

in my opinion, this made them look a bit ugly (it’s a proven fact that nice looking bike

kit is faster … read my highly acclaimed test results!). Once on the bike they were very

fidgety to set up and I needed a spacer block on the front mech to keep the chain clear

of the bottom of the front mech. Shimano Ultegra front mechs are believed to be one of

the ‘best’ fitting mechs as they have good clearances on the set up. Personally, I’m not

a fan of Shimano as Campag is so much faster (conclusively proven in independent

tests carried out … by me) as is Tiso which was my chosen front mech.  The Tiso

needed a little longer to set up so as to ensure no part of any of the chainring’s teeth hit

any part of the front mech cage.

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The block on the test bike was a 12-17 set up and with the 54 ring I found it very

smooth to pedal once I got over the initial ‘feel’ which was a bit on the ‘roller-coasterish’

side.  Although this was very noticeable to start with, after 15-20 minutes use it

appeared to become smoother … in fact I’d say it felt effortless once a good cadence

was reached.

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There were problems though!  These started when I engaged the 12 and 13 sprockets and the ring started to flex a lot, hitting both sides of the front mech cage.  No matter what I tried to do adjustment-wise, it wouldn’t stop rubbing. This was a big let down as it’s very clear that the rings are not as thick as they should be – they flex far too easily for my liking. A thicker TT version is available but I think I’d already made my mind up about the Osymetrics as (they say) it’s the first impressions that stick and to be honest I wasn’t impressed.  Having said that, I see no reason why the TT rings made from the thicker gauge alloy should flex any where near as much as those I tested … but I was keen to move on (on the first impression basis).  In any case, I still had the Rotors to try, my dinner was nearly ready and I was running out of test-time because it was going to get dark soon. 

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For the technically minded … 54x14 is the gear I used for the majority of the test and this resulted in a good solid, smooth ride.  Chain alignment was spot on. After each ride, breathing was a little rapid but eased down after 2-3mins once off the bike. Again recovery was quicker than with using round rings and legs felt pretty good too. I did try the inner ring and on the flat which resulted in a VERY jerky action especially when pedalling at a faster cadence. Under those circumstances, it definitely didn’t feel smooth at all. I would imagine on a climb it might well come into its own but I don’t have hills here to try it. I will of course up-sticks and move on to one of my hillier residences where I can carry out more tests if I ever receive any indications that the taxman is homing in on me, but for now I like the weather where I am and the flat roads are a bonus for someone with a time trialling background like mine.

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As far as the Osymetrics are concerned, in my opinion, the standard ones are poorly manufactured and I doubt that any quality inspection has been carried out.  The material is much too thin which results in a lot of flex.  They are a bit on the costly side too (although, of course, money is not an issue for me).

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Conclusion? If they did a TT version to fit Campag, I would definitely buy a set although I still believe the manufacturer needs to improve the quality issues.

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Rotor Rings

I was keen to get hold of a set of Rotor Rings as the ‘blurb’ promised smoother pedaling

action along with a number of other benefits listed on their website. For the purpose of

my tests, I opted for a set of Campag 53/40 rings which I found to be very well machined

and extremely easy to fit on my Campag cranks.  Mounting and ‘dialing in’ with the front

mech was very, VERY easy as everything only needed the tiniest bit of adjustment to

take into consideration the shape of the ring. Shifting from small to big ring was fine

although not as smooth as the original Campag round rings. It did however still feel quite

positive. Hardly any adjustment was needed on the rear mech and the chain line

remained the same. Flexing of these rings is hardly worth mentioning because they are

manufactured extremely well and solid.



Since testing the Osymetrics I took the view that a moving target was harder to hit

(with the taxman in mind) and decided a short break to another of my luxury homes was

maybe due. The terrain used for the testing of the Rotors was therefore slightly different

in that the roads were hillier but I’d lost a bit of weight (due to the worry of possibly

‘getting clobbered’ by HM C and E) so was able to adjust quite quickly.



There are 5 settings on the road rings, the recommended ‘starting’ setting being No. 3

which is where I started.



There is an awful lot of ‘blurb’ to read on Rotor’s website and contrary to man’s

impulsiveness to disregard instructions, ignore all the do’s and don’ts etc etc and just

crack on with it, I would highly recommend taking time out to read and inwardly digest it all if you really want to reap all the benefits.  It’s not a miracle aid to immediately win every race you enter and you’re not suddenly going to drop your buddies on the chain-gang … sadly. But there are gains to be made … so it’s worth persevering.



During my test I immediately noticed was how much smoother the pedalling action was.  It felt as if I was being tempted into using bigger gears, which I resisted sticking mainly to 53x17. My plan was to do 4 x 8km circuits to see what difference would be at the end but I actually continued to do an extra circuit (which had absolutely nothing to do with the very official looking vehicle parked outside my home … honest!). I believe this was due to the shape of the rings as I found pedalling action so much smoother I just wanted to ride a little further … which I did. During the circuit I also tried sprints where I noticed a difference in acceleration and responsiveness which was certainly in evidence sprinting out of sharp corners. It also felt as if different muscle areas of my legs were being put to work although I didn’t experience any post-ride stiffness that I tend to get with round rings after a similar ride.

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First impressions? I like them as I feel they are improving my pedalling action and are working all areas of my legs. Less lactate seems to be building up than before. Breathing seems a lot easier at this stage but more time on them needs to be done. I’ll continue riding them because Rotor’s website suggests that you’ll need to ride around 500kms, adjusting the setting as you go, before you find the one that suits your particular pedalling action.





How do the Osymetrics square up against Doval, the new kids on the block?  Go HERE to see what I think.

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