Oval cranks?

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  • Oval cranks?
  • quintet100
    Member

    Hi
    Anyone use oval cranks on their mtb? Are they any good.

    Premier Icon shortcut
    Subscriber

    Oval cranks? Or chain rings.

    quintet100
    Member

    Sorry chain rings

    Premier Icon FOG
    Subscriber

    had some back in the mists of time and to be honest I couldn’t tell any difference. There is one still on my winter roadbike

    robsoctane
    Member

    I remember something like Q red chain rings? Didn’t that Swiss guy that wins all the XC use them? Also, they came on Raleigh MTBs in the early days.

    If you buy one please review it for use

    Premier Icon Capt. Kronos
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    By heck… is it the late 80’s again!

    Premier Icon njee20
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    There are Rotor Q-rings and Osymmetric, neither are Biopace! 🙄

    pate
    Member

    I’m using Rotor Q-rings on my 29 er and my road bike and find them very good.

    b45her
    Member

    fabian barrel uses an oval ring on his mondraker foxy

    robsoctane
    Member

    @njee20: where Biospace rings oval? I thought they were. I know Q rings are oval. I didn’t mean that Q and Biospace are exactly the same rings! They’re both oval though, right?

    Anyway, have you tried them njee? Any good if so?

    Premier Icon turboferret
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    Just to be pedantic, there is a difference between elliptical and oval.

    I don’t think oval rings would be great.

    Cheers, Rich

    tazzymtb
    Member

    Use elliptical rings rotor Q and BETD rings. They do make a difference, and no they’re not biopace as the ellipse is in a different position an the were designed to do different things.

    used by lots of teams and race folks even wiggo had ellipticals.

    lots of in depth threads with links to research reports and stuff on this here forum about then if you have a look

    oh and according so some that don’t use them and haven’t tried them, they’re snake oil and it’s the 80’s again 😉

    Premier Icon DoctorRad
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    ‘Properly’ orientated oval rings – that is with the long axis through the power stroke, unlike BioPace – work very well for low gear / high RPM applications, especially when climbing or when carrying luggage.

    The proof of the pudding for me is returning to round rings and finding them ‘dead’ and harder work…

    barkit
    Member

    from Osymetric website :
    What is an OSYMETRIC curve?
    OSYMETRIC curve is not an oval or ellipse, is a dual cam, a TwinCam.
    What is a Twincam : 2 curves are symmetrical about a single point.

    Why is OSYMETRIC not an oval or ellipse?
    Neither the ellipse or oval and can solve the optimization of the strength of the leg using a crank.

    As tazzymtb said Wiggo used them for the last tour de France. Especially during the time trials; that being said if they are not better that round chainrings, at least they are not worse.

    Premier Icon big_scot_nanny
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    I remember hiring a bike from Ellis Bringham in Aviemore in about 1989, and on looking down could not figure out WTF was wrong with the bloody chainrings!

    Many years later I became aware of Biopace, and suddenly everything was clear. 😀

    but really, are they better? Really? Or is it more like me thinking white components make me faster (by 15% or so)?

    Kev

    barkit
    Member

    but really, are they better? Really?

    Do not mix biopace with Q-Ring or Osymetric rings. They are three completely different systems despite trying to tackle the same problem.

    Think that on a round chainring you have huge variations in terms of required energy input (depending at which position you are on the ring) to keep a given pace. Actually, the round chainring is less adapted than a chainring like Osymetric that compensates the variations.

    rewski
    Member

    I had biopace in the 80s, everyone including my LBS used to say I’d go through chains a lot quicker, that never really happened, nor did the perceived benefits to be honest, would be interested to try Q rotors, but they’re at the bottom of the a very long list of other bike gadgetry.

    cynic-al
    Member

    I can recall 1 test linked to on this topic only, and it was clearly biased. Also, a few people have bought them and think they are better.

    So for me, the jury’s out. The only benefit I can see is that you get through the dead spot more quickly. I don’t find time in the dead spot a limiting factor in my performance – can still easily get to max HR on round rings.

    I still say if they were deomnstrably better this would have been norne out in testing and EVERYONE would be using them.

    barkit
    Member

    I don’t find time in the dead spot a limiting factor in my performance

    I do, especially on technical climbs so that’s why I would fancy those just to give them a try. Maybe this is just a hype but I don’t think so, the idea makes sense to me.

    I still say if they were deomnstrably better this would have been norne out in testing and EVERYONE would be using them.

    That is not true, there are many examples of rather bad systems being widely used while better ones are available, they are however often not widely used for several reasons.

    Osymetric claims you are up to 10-12% more efficient which is already very good I think (if true). They also argue that you can easily check this figure yourself power measuring devices.

    cynic-al
    Member

    barkit – Member
    Osymetric claims you are up to 10-12% more efficient which is already very good I think (if true). They also argue that you can easily check this figure yourself power measuring devices.

    I bet they do. But why aren’t the teams using them decimating their competition? 10% is a HUGE performance increase.

    It’s a joke.

    Premier Icon D0NK
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    10% is a HUGE performance increase

    aren’t these figures for best vs worst case scenarios? In cycling there’s so much emphasis on rider ability that once you get to elite level any technical improvement is tiny whereas for you and me it would be a marked improvement (10% still sounds a lot tho).

    no idea whether funky shaped rings are any good, I get the power and dead spots but if you ‘help’ the dead spot aren’t you increasing your effort on the usual power part, helping you in one area but gimping you in another? evening out the torque out which presumably would be great in a motor but bodies are a bit different

    barkit
    Member

    cynic-al – Member
    why aren’t the teams using them decimating their competition?

    In theory yes, I think DONK just provided the perfect reply to your question. I remember the Sky team used to hide the brand on the chainrings so their competitors would not notice and copy them right away.

    DONK – Member
    if you ‘help’ the dead spot aren’t you increasing your effort on the usual power part

    It’s a matter of optimzing your effort; your remove “resistance” where you are the weaker (i.e. around the dead spot) and you add what you substracted in terms of diameter at the moment where you reach your maximum power. With a round chainring, there is some “waste” every turn.

    Premier Icon DoctorRad
    Subscriber

    I don’t find time in the dead spot a limiting factor in my performance

    I do, especially on technical climbs so that’s why I would fancy those just to give them a try. Maybe this is just a hype but I don’t think so, the idea makes sense to me.[/quote]

    Back in my Calderdale days, my elliptical rings certainly helped with technical climbs. They get you through the dead spot quicker, and mean you have an higher effective gear through the power stroke, which means the back wheel is less likely to lose traction. What’s not to like?

    My granny ring was 40% ‘ovality’ which means it was effectively a 20-tooth through the dead spot, and 28-tooth through the power stroke. Unfortunately, with the demise of EggRings, you can no longer buy rings which are this elliptical, but every little helps.

    Premier Icon DoctorRad
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    It’s a matter of optimzing your effort; your remove “resistance” where you are the weaker (i.e. around the dead spot) and you add what you substracted in terms of diameter at the moment where you reach your maximum power. With a round chainring, there is some “waste” every turn.

    They increase the integral of the product of your legs’ force input and the mechanical advantage of the crank/chainring combination over a complete crank revolution.

    Or something… 😉

    barkit
    Member

    They increase the integral of the product of your legs’ force input and the mechanical advantage of the crank/chainring combination over a complete crank revolution.

    It couldn’t have been explained any better 🙂 !

    Premier Icon Northwind
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    I think I’d be interested to try them, but they seem pretty pricy for what they are… £71 for an unramped chainring?

    cynic-al
    Member

    If it was priced reasonably it wouldn’t have the same allure.

    matt1986
    Member

    I can’t see the benefits of it neither can the people I know who have used them for road racing

    Premier Icon DoctorRad
    Subscriber

    I can’t see the benefits of it neither can the people I know who have used them for road racing

    Road racing is not where they excel. As I said above, most effective on technical climbs and when carrying luggage.

    tazzymtb
    Member

    wouldn’t know about gearies but on a singlespeed they do make a difference, you can go up 2-4 teeth on the front for the same perceived effort, the top speed spin is much more comfortable without feeling that your knees are wrecking and on steep thrutcy climbs they can make the difference between cleaning a climbing and walking. you don’t have chain drop issues either as long as you know how to set the tension. SS elliptical rings can be had for 35-45 quid so not a massive price either.

    I hate riding round rings now, just feels gash.

    walleater
    Member

    Some of us mounted Biopace rings ‘incorrectly’ BITD which pretty mimics the current rings. Then we learnt to pedal with a cadence of more than 30rpm and discovered how amazing new fangled round rings were….

    tazzymtb
    Member

    Then we learnt to pedal with a cadence of more than 30rpm and discovered how amazing new fangled round rings were….

    does not compute, elliptical rings help high cadence and smooths out your pedal stroke 😕

    Premier Icon Northwind
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    cynic-al – Member

    If it was priced reasonably it wouldn’t have the same allure.

    Oh you nasty, accurate cynic!

    walleater
    Member

    does not compute, elliptical rings help high cadence and smooths out your pedal stroke

    Since when is pedalling at high cadence not smooth on a fell fitted bike? I’d argue that a coaching session would help much more.

    tazzymtb
    Member

    I’d agree to a certain extent, but again my comments are based on SS, on a road bike, turbo or tack bike I can spin high cadence smoothly. Spinning out an SS mtb is never as smooth, for me personally a wibbly wobbly thing makes it smoother and gives me a higher cadence or more i can hold the higher cadence that bit longer. Like i always say, it works for me others may **** hate it. But don’t compare it to biopace and then poopoo it without giving it a go.

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