Advertise on Bikeforums.net



User Tag List

Results 1 to 8 of 8

Thread: compact cranks

  1. #1
    Senior Member hendrick81's Avatar
    Join Date
    Apr 2008
    Location
    Sandy Eggo
    My Bikes
    2006 caad8, 2010 caad9 1, 2011 caad10 4
    Posts
    2,123
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    compact cranks

    What are the advantages and disadvantages of a compact.

  2. #2
    THIS SPACE FOR RENT
    Join Date
    Jan 2006
    Posts
    2,849
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Type compact crank into the search function, select "search titles only," and select the road forum as the forum to search, and you will get 119 threads.
    "I don't buy new frames, it just encourages them."

    -T.G.

  3. #3
    Banned
    Join Date
    Feb 2008
    Location
    Hampshire UK
    My Bikes
    Specialized + Pinarello
    Posts
    265
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Advantages - smaller range of gears
    Disadvantage - smaller range of gears

  4. #4
    Senior Member re-cycler's Avatar
    Join Date
    Sep 2004
    Location
    Piedmont of NC
    My Bikes
    2007 Serotta Fierte Ti ; 2003 raleigh m-80 ; 1983 Motobecane Grand Touring (being transformed into Townie)
    Posts
    354
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by cyclingvirtual View Post
    Advantages - smaller range of gears
    Disadvantage - smaller range of gears
    rock on.

  5. #5
    THIS SPACE FOR RENT
    Join Date
    Jan 2006
    Posts
    2,849
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by cyclingvirtual View Post
    Advantages - smaller range of gears
    Disadvantage - smaller range of gears
    To quote Botto, incorrect. It's a wider range (47% jump between the rings for 50/34 versus 36% for 53/39). Unless you mean versus a triple, but triples are so out of fashion that only people like me run them.
    "I don't buy new frames, it just encourages them."

    -T.G.

  6. #6
    Used to be a climber.. GuitarWizard's Avatar
    Join Date
    Aug 2005
    Location
    North Providence, RI
    My Bikes
    None at the moment
    Posts
    6,821
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I have a great range of gears with my 50/36 combined with my 11-26 cassette. Works very well for racing too.
    1999 Trek 2500 - hit by a car on it in May, 2011 and currently bikeless

  7. #7
    My leg made the cover! tjspahr's Avatar
    Join Date
    Dec 2007
    Location
    Franklin, IN
    My Bikes
    Trek, Arbourne, BMC, Orbea
    Posts
    460
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Landgolier View Post
    To quote Botto, incorrect.
    +1
    "If it first you don't succeed, try, try again. Then quit. There's no use being a damn fool about it." - W.C. Fields

  8. #8
    Bike ≠ Car ≠ Ped. BarracksSi's Avatar
    Join Date
    Jul 2007
    Location
    Washington, DC
    My Bikes
    Some bikes. Hell, they're all the same, ain't they?
    Posts
    13,858
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Landgolier View Post
    To quote Botto, incorrect. It's a wider range (47% jump between the rings for 50/34 versus 36% for 53/39).
    Right, it's a wider range, which is good; it's also a bigger jump between the two chainrings, which can be bad. The quality of that shift mainly depends on the crank itself (my 50/34 actually shifts a bit smoother & more dependably than the standard 53/39 it replaced), but the important part is that the ratios see a bigger jump.

    Say that, on the 53/39, maintaining your cadence through one FD shift means also shifting the RD three or, possibly, two cogs to get another ratio that's close to the one you were pedaling a few seconds earlier. On the 50/34, you'd have to shift the RD three or four cogs for the same result.

    That ratio jump also depends on the gearing of the cassette. If the whole thing is in one-tooth increments, it's hardly an issue; if it starts jumping by 2- and 3-tooth increments, you'll notice the gaps in ratios even more with a compact than a standard.

    So here's the pros & cons as I see them now:

    A compact can get you a wider range, and can give you a lower low gear and retain a tall high gear depending on the cassette. It can also give you a slightly wider range than, or similar range to, a standard crank if you get a narrow-range cassette, but with finer increments between each cog.

    But, changing chainrings on a compact, especially a 50/34, is definitely a bigger jump in ratios. You may end up staying on one chainring more often just to cut down on simultaneous front-rear shifting.

    Those are the aspects I'd weigh against each other.

Posting Permissions

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