Results 1 to 11 of 11
  1. #1
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    179

    Worn out BB bearings suitable replacement?

    I have an 05' Giant trance that came with a TruVative FireX crank and Truvative ISIS BB. I'm thinking that the bearings are on their way out as I keep developing play from the crank in the BB. I've tightened up the nut(s) for the BB and after a ride its loose again. I've read that the TruVative Crank arms have a reputation of coming loose, but this not the arm in relation to the crank. It is the crank riding in the BB.

    So in short, what is a good replacement bottom bracket for this crank setup? Should I replace it with another TruVative BB or are there better alternatives in a compareable price range?

  2. #2
    mtbr member
    Reputation: Shalom's Avatar
    Join Date
    Nov 2008
    Posts
    2,002
    Any ISIS BB should do the job.

  3. #3
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    179
    Thanks for the response. I'm seeing that there are multiple sizes available on Pricepoint. How do I know what size I should use?

  4. #4
    Rub it............
    Reputation: frdfandc's Avatar
    Join Date
    Sep 2007
    Posts
    3,822
    Your going to have to measure the shell of the bottom bracket (frame) and then measure the spindle of the bottom bracket (overall length) to get the correct one.

    Depending on the frame it will either be a 68mm shell or 73mm shell as those are your only 2 choices. Spindle length should be 113mm.

    If the bolts holding the crank arms to the spindles keep coming loose, then the crank arm/spindle interface could possibly be damaged. So a new BB will not fix this problem. The crank arms will need to be replaced IME.

    I prefer the Shimano SLX Hollowtech II or the new Sram 1400 non-series GXP crank systems to be a great replacement for the FireX.

  5. #5
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    179
    Thanks frdfandc. I checked very carefully after reading about the common problems w/ crank arms on Truvative cranks and the arms are secure and tight on the crank. So no problem there. This is where the actual crank runs through the BB that I keep developing play.

    After finding a BB data base online it appears that the Truvative BB that I have is 113mm. The BB I found on Pricepoint shows as 68/73x113. It seems this would be the correct dimensions for my bike. I will double check the shell measurement on the frame when I get home.

  6. #6
    Vitamin Bike Added
    Reputation: MTBCanuck's Avatar
    Join Date
    May 2011
    Posts
    545
    Let me build on this question by asking about spindle length. I have a stock giant iguana with a spindle length on the BB of 118mm. 188mm seems longer than the standard, can I get away with a 113? Currently in the market for a new BB as well.
    Keep the rubber side down

  7. #7
    Rub it............
    Reputation: frdfandc's Avatar
    Join Date
    Sep 2007
    Posts
    3,822
    Quote Originally Posted by MTBCanuck View Post
    Let me build on this question by asking about spindle length. I have a stock giant iguana with a spindle length on the BB of 118mm. 188mm seems longer than the standard, can I get away with a 113? Currently in the market for a new BB as well.

    BB spindle length is dictated by the crank set itself. One brand my require a 113mm spindle length, another might need 118. Stick to what is in the bike. This will help prevent the crank from making contact with the frame. Anything narrower the inner or middle chain ring could contact the chain stay, or the crank arm from hitting the chain stay.

  8. #8
    mtbr member
    Reputation:
    Join Date
    Sep 2011
    Posts
    3
    Do you think its possible to put an external bearing bb on my 2008 trek jack? I takes a shimano ES25 octalink now. Are there any advantages to external bearing bb's? Thanks

  9. #9
    Rub it............
    Reputation: frdfandc's Avatar
    Join Date
    Sep 2007
    Posts
    3,822
    Quote Originally Posted by kpman View Post
    Do you think its possible to put an external bearing bb on my 2008 trek jack? I takes a shimano ES25 octalink now. Are there any advantages to external bearing bb's? Thanks

    Not really. Maybe a tad lighter. But you would also have to replace the entire crank. A larger expenditure of funds.

    If your looking for a good ISIS BB, Crank Brothers make a nice one.

  10. #10
    mtbr member
    Reputation: Dougal's Avatar
    Join Date
    Jan 2004
    Posts
    3,141
    Truvativ ISIS Bearings are replacable. The size is 21.5x31.7mm. Some BB's use a double wide version which is 14mm wide. This is a bike specific bearing size, you won't find it at an industrial bearing supplier.

    I'm just replacing the bearings now in a firex ISIS crankset I've been riding since 2004, the BB is from around 2005 and yes 113mm is the right size axle. Initially I had a 118 and the chainline was wrong.
    Owner of www.shockcraft.co.nz and NZ Manitou Service Agent.
    www.dougal.co.nz Suspension setup & tuning.
    SPV Devolve

  11. #11
    mtbr member
    Reputation: Dougal's Avatar
    Join Date
    Jan 2004
    Posts
    3,141
    Quote Originally Posted by kpman View Post
    Do you think its possible to put an external bearing bb on my 2008 trek jack? I takes a shimano ES25 octalink now. Are there any advantages to external bearing bb's? Thanks
    Octalink is a shimano standard and only shimano make BB's for it. Your cheapest option is simply to buy another shimano octalink BB.
    External bearing BB's have stiffness advantages but due to their design have issues with water egress which can result in very short bearing life.
    Owner of www.shockcraft.co.nz and NZ Manitou Service Agent.
    www.dougal.co.nz Suspension setup & tuning.
    SPV Devolve

Similar Threads

  1. suitable delirium replacement
    By delirian in forum Knolly
    Replies: 19
    Last Post: 09-05-2011, 03:55 PM
  2. Are my bearings worn.. already?
    By Roasted in forum Wheels and Tires
    Replies: 6
    Last Post: 09-08-2010, 03:53 AM
  3. Is this a suitable replacement RD?
    By buickid in forum Drivetrain - shifters, derailleurs, cranks
    Replies: 12
    Last Post: 01-14-2010, 09:09 PM
  4. Pivot/bearings are worn out when???
    By Dunc in forum Downhill - Freeride
    Replies: 4
    Last Post: 02-23-2009, 02:50 PM
  5. Anyone with worn DU bearings?
    By Steve-O in forum Shocks and Suspension
    Replies: 5
    Last Post: 03-24-2004, 12:14 PM

Posting Permissions

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