Oval chainrings- Mtbr.com
Results 1 to 5 of 5

Thread: Oval chainrings

  1. #1
    mtbr member
    Reputation:
    Join Date
    Apr 2014
    Posts
    100

    Oval chainrings

    I just want to make sense of this new advancement in chain-ring technology.

    As I understand it, what makes an oval chain-ring more efficient is because the oval shape allows more leverage in the power stroke of the pedaling motion, and to a lesser degree, less leverage during the up-stroke of the pedaling motion.

    So, in order to improve pedaling efficiency, an oval shape allows more force to be exerted during the down-stroke motion, but less energy to be exerted during the up-stroke motion.

    I see this as only half an improvement, since energy is being lost during the up-stroke motion. Not only that, if more force is being exerted during the down-stroke motion, wouldn't this put more stress on the teeth in that area?

    How long will an oval chain-ring last in comparison to a circular one?

  2. #2
    mtbr member
    Reputation: fefillo's Avatar
    Join Date
    Jul 2014
    Posts
    403

    Oval chainrings

    Quote Originally Posted by Pocket Lint View Post
    I just want to make sense of this new advancement in chain-ring technology.

    As I understand it, what makes an oval chain-ring more efficient is because the oval shape allows more leverage in the power stroke of the pedaling motion, and to a lesser degree, less leverage during the up-stroke of the pedaling motion.
    Yes.

    Quote Originally Posted by Pocket Lint View Post
    So, in order to improve pedaling efficiency, an oval shape allows more force to be exerted during the down-stroke motion, but less energy to be exerted during the up-stroke motion.
    Yes.

    Quote Originally Posted by Pocket Lint View Post
    I see this as only half an improvement, since energy is being lost during the up-stroke motion. Not only that, if more force is being exerted during the down-stroke motion, wouldn't this put more stress on the teeth in that area?
    Probably.

    Quote Originally Posted by Pocket Lint View Post
    How long will an oval chain-ring last in comparison to a circular one?
    Who knows. At best some marginal percentage less than a circular ring, at worst half the life of a circular ring of the same amount of teeth and material.


    Sent from my iPhone using Tapatalk

  3. #3
    mtbr member
    Reputation: borabora's Avatar
    Join Date
    Feb 2011
    Posts
    1,069
    I know nothing about oval chainrings but this being an internet forum I am nonetheless happy to offer my expertise:

    Whenever your feet are in the "most power" position (probably 3 and 9 o'clock) you benefit from a large chainring while when your feet are in the least power position (12 and 6 o'clock) you want a small chainring. An oval chainring can help solve that little conundrum as an oval is a circle with a variable radius...:-)

  4. #4
    manufacturer
    Reputation: tehan's Avatar
    Join Date
    Jan 2007
    Posts
    877
    Hi,
    Just found this thread by accident.
    I want to put few things straight.
    To not to repeat what is written on our website under oval chainrings I will write the info you look for.

    Oval rings help even out your pedal stroke. You are not machine to put same torque over 360deg pedal motion. You only use effective stroke from 3oclock to max 5 oclock. That is all. Shocking, I know but this has been proven hundreds of times in laboratory tests on famous cyclists like Armstrong by independent Universities...

    Now. Oval chainrings will not wear out quicker than round rings. Having 32T oval is like pedaling one of 31T round equivalent but technically where you push in "power zone" you actually pedal 34T round ring in that range. So 32T oval will not wear out quicker than 34T round. Does that make sense to you?

    I can promise you that our oval ring will outlast any other chainring you have had in the past. Our rings have reputation to last about 3x longer than original Sram xx1 ones for eg. If you are an average rider you will get minimum 12 months of it at least (provided you will change chains min 3 times in that period to not to prematurely damage the ring and cassette - that is a standard practice btw, not an "oval" requirement).

    If you look at the chainring in motion you will realize that at any given point chain is wrapped on exactly half of the ring (same amount of teeth). So there is exactly ssame stress level to oval as it is to round. Sounds not logical but a proper oval shape if cut thru center at any given angle will always produce 2 equal half's - same as circle.

    Now back to durability. If you ride 30T round chainring now and swap to 30T oval - the oval will live longer. This is because at the power point (3-5 oclock) there is bigger radius (equivalent of 32T round ring) compared to 30T round. So chain sits on the chainring with more relaxed angle = less wear. The bigger the chainring is the less wear and friction you get. This is well documented in Singlespeeds. Yuo can use same ratio with small rings and big rings to get same speed and effort. But only with bigger rings you get leas wear as chain is at less of an angle. Think how you wrap the chain on 11T cog versus 18T cog for example.


    hope that clears some of your concerns. I believe that if you want to change something in your bike to gain improvement then out of all things you can buy to your bike, Oval rings are the ones where you will see most dramatic change on performance and joy from ride.

  5. #5
    mtbr member
    Reputation: RS VR6's Avatar
    Join Date
    Mar 2007
    Posts
    5,177
    From what I understand...the majority of the wear on narrow wide rings come from chainline. Its the sides of the outside facing teeth that wear. So the more extreme the chainline is in the larger cogs...the faster the chainring will wear. I guess if you use the large cogs often...then your chainring will wear faster.

Similar Threads

  1. AbsoluteBlack 32 or 34T 104BCD Oval Chainrings
    By jp08865 in forum Where are the Best Deals?
    Replies: 2
    Last Post: 11-23-2014, 02:43 PM
  2. Oval chain rings for SS
    By Lampshade29 in forum Singlespeed
    Replies: 5
    Last Post: 08-19-2014, 01:16 PM
  3. Oval shape tires
    By jwhan in forum Fat bikes
    Replies: 7
    Last Post: 08-03-2014, 07:45 AM
  4. Training On Oval And Round Chainrings?
    By GraemeTee in forum XC Racing and Training
    Replies: 14
    Last Post: 02-01-2014, 12:38 PM
  5. Replies: 1
    Last Post: 10-08-2012, 01:26 PM

Members who have read this thread: 0

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2020 VerticalScope Inc. All rights reserved.