another dull compatibility question!!

Discussion in 'Cycling Equipment' started by robsy, Sep 11, 2009.

  1. robsy

    robsy New Member

    Joined:
    Nov 29, 2006
    Messages:
    18
    Likes Received:
    0
    I know this has been discussed many times before but the info i have gathered is confusing and contradictory.
    I have a 7 speed drivechain and need new cranks. Will a 9 speed cranset work well enough with my 7 speec chain and fit my current BB? The bike is a 16 yr old Dawes with 400 EX components.

    Thanks!
    Robsy
     
    Tags:


  2. alfeng

    alfeng Well-Known Member

    Joined:
    Jul 23, 2005
    Messages:
    6,723
    Likes Received:
    126
    You can use almost any NEW crankset which your wallet will allow ...

    However, because your current Bottom Bracket probably has a square taper spindle you will need to buy a NEW bottom bracket, too.

    Which crankset(s) were you considering?

    Have you considered simply changing the chainrings and/or replacing the bike's current Bottom Bracket?
     
  3. robsy

    robsy New Member

    Joined:
    Nov 29, 2006
    Messages:
    18
    Likes Received:
    0
    not exactly sure at the moment. perhaps shimano tiagra but to be honest it doesn't really matter. My pedal dropped out the other day as the threading on one of the cranks is gone.
    I have been told before that 9 and 10 speed cranksets would be a problem with my 7 speed setup.
     
  4. Peter@vecchios

    [email protected] New Member

    Joined:
    Dec 30, 2007
    Messages:
    2,111
    Likes Received:
    4
    I use a 8s chain on a 10s chainrings crank(friction shifters and old C-Record front derailleur from 1986 or so) and it works just fine.
     
  5. robsy

    robsy New Member

    Joined:
    Nov 29, 2006
    Messages:
    18
    Likes Received:
    0
    So BB these days arent squared tappered?
     
  6. alfeng

    alfeng Well-Known Member

    Joined:
    Jul 23, 2005
    Messages:
    6,723
    Likes Received:
    126
    IMO, your source is generally incorrect ...

    The known (to me) exception MIGHT BE, but probably not, a 10-/11-speed Campagnolo crankset because instead of increasing the ramping on the chainrings, Campagnolo chose to machine the large chainring by a fraction of a millimeter to allow it to sit a little closer to the inner chainring ...

    And, because Peter indicates that he doesn't have a problem using 10-speed chainrings with an 8-speed chain, you shouldn't either.
     
  7. alfeng

    alfeng Well-Known Member

    Joined:
    Jul 23, 2005
    Messages:
    6,723
    Likes Received:
    126
    Welcome to the 21st Century.
     
  8. robsy

    robsy New Member

    Joined:
    Nov 29, 2006
    Messages:
    18
    Likes Received:
    0
    ah, but i have a 7 speed chain!
     
  9. alfeng

    alfeng Well-Known Member

    Joined:
    Jul 23, 2005
    Messages:
    6,723
    Likes Received:
    126
    There is generally NO DIFFERENCE between a 7-speed & an 8-speed chain ...

    BUT, if there is, then buy an 8-speed chain ... chains have to be replaced at periodic intervals AND your's is probably ready to be replaced.
     
  10. robsy

    robsy New Member

    Joined:
    Nov 29, 2006
    Messages:
    18
    Likes Received:
    0
    ok, i am more convinced now although a syou say i may have to buy a new BB also if i cannot find a square tappered crankset?

    If i were to buy a new wheelset with an 8 or 9 speed hub is it easy enough to use spacers with my old 7 speed cassette?

    thanks again
     
  11. alfeng

    alfeng Well-Known Member

    Joined:
    Jul 23, 2005
    Messages:
    6,723
    Likes Received:
    126
    Yes, a spacer is used when intalling a 7-speed cassette on a wheel with an 8-/9-speed freehub.

    BTW. Repacking the bearings on your current wheels is something you should probably consider before buying a new set of wheels.
     
  12. Peter@vecchios

    [email protected] New Member

    Joined:
    Dec 30, 2007
    Messages:
    2,111
    Likes Received:
    4
    7s chain and '8s' chain unless it's really old, are the same dimension but even so, no problem.
     
  13. robsy

    robsy New Member

    Joined:
    Nov 29, 2006
    Messages:
    18
    Likes Received:
    0
    its never ending...
    will an Octalink BB fit my frame i wonder.
     
  14. alfeng

    alfeng Well-Known Member

    Joined:
    Jul 23, 2005
    Messages:
    6,723
    Likes Received:
    126
    Yes.
     
  15. robsy

    robsy New Member

    Joined:
    Nov 29, 2006
    Messages:
    18
    Likes Received:
    0
    thanks for the help alf

    the reason i may get new wheels is because i would like some lighter more responsive ones. but to be honest i don't know whether it is more the frame which gives you a more responsive ride or the wheels.

     
  16. alienator

    alienator Well-Known Member

    Joined:
    Jun 10, 2004
    Messages:
    12,596
    Likes Received:
    160
    It's the rider that gives the bike a responsive ride. Lighter wheels don't provide a significant performance benefit.

    As for square taper BB's, Phil Wood still sells them, and the PW square tapers are some of the best you can get.
     
  17. curby

    curby New Member

    Joined:
    May 9, 2006
    Messages:
    218
    Likes Received:
    0
    Maybe consider finding the bottom bracket size of what you have in the frame, find a square taper crank that uses that size, -OR- your bottom bracket is due for replacement anyway, buy a FSA Gossamer crank and bottom bracket on eBay, I saw one this week new for $60-, get the bike shop to install it. -OR- really cheap alternative, have your crankarm fixed with a threaded insert, 20 years ago this worked fine for my loaded touring bike over all the mountains I could find! the bonding agents today are probably even better! I would probably not recommend this fix for a racing bike that I sprint out of the saddle constantly (piece of mind).
     
Loading...
Loading...