Advertise on Bikeforums.net



User Tag List

Results 1 to 9 of 9
  1. #1
    Senior Member kamtsa's Avatar
    Join Date
    Dec 2008
    Posts
    1,815
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Help me selecting a chainring for my bike

    My touring bike has a DualDrive 3x9 with SRAM DualDrive, single 46T 110mm Suginu chainring, ERTO 406 Kojak wheels and SRAM pc951 chain. This results in a gear inch range of 19.6” to 106”.

    I would to move down the range by changing the chainring from 46T to 40T. I found on Amazon several 40T 110mm chainrings but am not sure which will be the best fit my bike and what are the differences between them, quality wise:

    http://amzn.com/B001GSQV9O
    http://amzn.com/B001CJXDS4
    http://amzn.com/B001GSOHF4
    http://amzn.com/B000C15JYY

    Any suggestion? Will any 40T 110mm chainring fit my bike? Does the quality of the chainring matter (I don’t have FD if it makes a difference) or are they all the same?

    Also, how much should I shorten the chain when going from 46T to 40T?

    Thanks,

    Kam

  2. #2
    cab horn
    Join Date
    Jun 2004
    Location
    Toronto
    My Bikes
    1987 Bianchi Campione
    Posts
    28,295
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Did I read that correctly? You're running a single chainring on a triple crank? Anyways, that surly *stainless* chainring would be the best out of the ones you listed. Although the rest of those (al rings) are fine as well. Do the proper chain sizing when you throw the 40t on. e.g big/big method. This gives you the correct chain length.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

  3. #3
    Senior Member
    Join Date
    Jul 2006
    Location
    El Segundo, Ca.
    My Bikes
    '93 Performance R203, '83 Bianchi 980
    Posts
    215
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    believe the op is refering to a rear hub that has an internal 3 speed and a 9 speed cassette, hence
    no FD, agree with the stn stl gear and shorten chain as needed.

  4. #4
    cab horn
    Join Date
    Jun 2004
    Location
    Toronto
    My Bikes
    1987 Bianchi Campione
    Posts
    28,295
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Oh you're right. Brain fart...
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

  5. #5
    Senior Member kamtsa's Avatar
    Join Date
    Dec 2008
    Posts
    1,815
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thanks operator and roberth33tiger.

    Kam

  6. #6
    Senior Member
    Join Date
    Dec 2004
    Location
    Athens, Ohio
    My Bikes
    Custom Custom Custom
    Posts
    5,104
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Surly would last the longest. Then the Profile, FSA and last Sugino

  7. #7
    Senior Member
    Join Date
    Aug 2005
    Location
    Pittsburgh, PA
    My Bikes
    '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
    Posts
    26,171
    Mentioned
    13 Post(s)
    Tagged
    0 Thread(s)
    Be sure the SRAM hub doesn't have a minimum gear ratio specification, i.e. the smallest chainring/largest cog combination they recommend. If you gear it too low there is a possibliity that the excess torque could damage the internal gearing.

    BTW, 19.5 gear-inches is REALLY low. Do you need a still lower gear?

  8. #8
    Senior Member kamtsa's Avatar
    Join Date
    Dec 2008
    Posts
    1,815
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by HillRider View Post
    BTW, 19.5 gear-inches is REALLY low. Do you need a still lower gear?
    Actually I need more strength ;-)

    Seriously, some of the hills I climb are unsustainable for me. That is, I can climb them for limited distance and it is getting harder as I go.

    Kam

  9. #9
    Senior Member kamtsa's Avatar
    Join Date
    Dec 2008
    Posts
    1,815
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by HillRider View Post
    Be sure the SRAM hub doesn't have a minimum gear ratio specification, i.e. the smallest chainring/largest cog combination they recommend. If you gear it too low there is a possibliity that the excess torque could damage the internal gearing.
    Let's say for a given hill and my current lower gear I go at 3mph. If I reduce the chainring to 40T and go at speed <= 3mph, the torque on the IGH is not increased, right?

    My goal is to keep the same cadence as now but to reduce the force on the pedals (that is, lower power and lower forward speed).

    Does this make sense?

    Kam

Posting Permissions

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