Advertise on Bikeforums.net



User Tag List

Results 1 to 8 of 8
  1. #1
    Senior Member
    Join Date
    Feb 2008
    Location
    El Cerrito, California
    Posts
    109
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Yet ANOTHER Bottom Bracket question:

    I'm running a stock Truvativ Powerspline BB 68x108 with Truvativ Touro 48t Crankset.

    I'd like to replace both.

    Would my chainline be affected if I got a BB that is 68x107?
    I'm so new to Bottom Brackets, I'm replacing this BB/Crankset because it's a year old.
    Or do I need to? I've ridden it hard since last January...

    Any suggestions or advice is great help, thanks!
    The first time I asked about purchasing a 2008 TK2 frameset, all they would tell me is that it was expensive and only for track riding. They actually wouldn't even give me the price. They just kept saying we sell it for MSRP, and went on to sell a langster to some bro with a poped collar.
    -SaveTheRock

  2. #2
    Senior Member
    Join Date
    Mar 2007
    Location
    Rohnert Park, CA
    My Bikes
    Pake track, Soma DoubleCross, LeMond Etape, Maruishi RoadAce 303
    Posts
    1,248
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    No, you don't need to replace them if there is nothing wrong with them.

  3. #3
    aka mattio queerpunk's Avatar
    Join Date
    May 2005
    Posts
    5,323
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by chore4n View Post
    I'm running a stock Truvativ Powerspline BB 68x108 with Truvativ Touro 48t Crankset.

    I'd like to replace both.

    Would my chainline be affected if I got a BB that is 68x107?
    I'm so new to Bottom Brackets, I'm replacing this BB/Crankset because it's a year old.
    Or do I need to? I've ridden it hard since last January...

    Any suggestions or advice is great help, thanks!
    First - why replace them? My roommate rode that crank/bb hard for three years without needing to replace it.

    Secondly, this doesn't make any sense:
    "Would my chainline be affected if I got a BB that is 68x107?"
    Here's why. The spindle of a bottom bracket doesn't affect a chainline alone. It's the crank and spindle put together that determines how far away from the bike's centerline the chainring will be located. That is chainline. Asking if a bottom bracket will do something to your chainline is a meaningless question without saying anything about what crank you'll use.

    Don't go out and buy a bottom bracket. Go out and buy a crank, and then buy a matching bottom bracket that will get you near enough to an appropriate chainline.

    Some people get all anally retentive about chainlines, but getting within 2-4mm is plenty accurate.
    the hipster myth.

    i practice vagabondery.

  4. #4
    big ring MIN's Avatar
    Join Date
    Mar 2007
    Location
    philadelphia
    Posts
    5,839
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Random fact, I measured the Touro chainline at 41mm (road standard for inner position). Most rear hub chainlines are 42mm plus the cog offset. For instance, my Formula with EAI cog yields a 43.5mm chainline.

    And +1 to mattio.

  5. #5
    Senior Member RoyIII's Avatar
    Join Date
    Apr 2008
    Location
    Waxahachie, Texas
    My Bikes
    Gios Compact Pro (mostlyChorus 10), Gios fixed gear, Pedal Force RS2 (Chorus 10)
    Posts
    452
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Leave it alone, is my 2 cents. Instead of fooling with the bb, go out and ride!

  6. #6
    :)
    Join Date
    Nov 2006
    Location
    duluth
    My Bikes
    '07 Pista, '09 Fantom Cross Uno, '8? Miyata, '67 Stingray, '0? Zoo mod trials, Tallbike, Chopper, '73 Schwinn Collegiate, '67 Triumph Chopper, '69 CB350, '58 BSA Spitfire, '73 CB450
    Posts
    3,391
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    If a bb doesn't last a year, something is truly wrong.

    People have ridden 1+ year long trips from Argentina to Alaska on the same bb (with fully loaded bike).

  7. #7
    Senior Member
    Join Date
    Feb 2008
    Location
    El Cerrito, California
    Posts
    109
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Okay, I've decided not to replace it.
    But it feels so strange...and makes sounds that I've checked on Sheldon Brown's site, but I still haven't concluded what the sounds are.
    Well, if it works don't jock it, right?
    Thanks guys.
    The first time I asked about purchasing a 2008 TK2 frameset, all they would tell me is that it was expensive and only for track riding. They actually wouldn't even give me the price. They just kept saying we sell it for MSRP, and went on to sell a langster to some bro with a poped collar.
    -SaveTheRock

  8. #8
    Large Member Geordi Laforge's Avatar
    Join Date
    Nov 2008
    Posts
    1,497
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    what is the condition of the bottom bracket? what sounds are you talking about? are you sure the sound is coming from the bb? remove them and check.

    if the bb is not serviceable and it's not spinning like it's supposed to, then yes, you should replace it with another.

Posting Permissions

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