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Please advice how to determine which BB size

slowrunnerslowrunner Posts: 5
edited June 2010 in MTB workshop & tech
Hi,

I have a Ridley Tiger mountain bike frame and I try to get a BB for it. I have send an email to Ridley to ask about the which BB standard is used in my frame but I have waited for a week, still no response from them.

I have measued my BB shell width is 68mm. Just wonder how do I know that I require British/ISO, Italian, French.


Please advice.

Thanks,
Adrian.

Posts

  • Its a standard 68mm bottom bracket.

    If using an interface BB + crankset (such as ISIS/square taper) you will also need to know what spindle length you need.

    Any 68mm external BB + crankset (such as Shimano HT2) should fit fine.
  • stuart_c-2stuart_c-2 Posts: 805
    How is the spindle length measured? (Where from/to?)

    I have a similar issue.

    Cheers
    "I ride to eat"
  • stu8975stu8975 Posts: 1,334
    Stuart_C wrote:
    How is the spindle length measured? (Where from/to?)

    I have a similar issue.

    Cheers

    Measure from one end of the spindle to the other, length required depends on what's recommended for the chainset you are using.
  • S_J_PS_J_P Posts: 908
    Most foolproof way to determine the correct dimensions is to remove the old BB and take a look. The dimensions should be printed on the BB surface.
  • S_J_P wrote:
    Most foolproof way to determine the correct dimensions is to remove the old BB and take a look. The dimensions should be printed on the BB surface.
    if you have a BB that is!
  • nicklousenicklouse Posts: 50,675 Lives Here
    or see what the cranks say you need, shimano list it in the manuals.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • I brought the frame only and I intend to transfer my current components on it. So I have no BB or cranket to refer to.

    My current bike fited with Shimano XT crankset (external cup 68mm British/ISO) and I just couldn't screw it in, seem like the thread doesn't fit. I searh on the internet and found that there are few standard in bottom bracket threading, like British/ISO, Italian and French. I need your advice how to determine which BB standard is used in the Ridley frame.

    Thanks.
  • stu8975stu8975 Posts: 1,334
    Ridley - model/year? they all seen to come with std MTB chainsets (well back to 2007) so doubt they would use a different thread. Pic of the BB shell/threads might help.
  • It is Ridley Tiger frame, I guess it should be 2005 model.

    I have the photo but sorry I have no idea how to upload it to this forum. Any suggestion.
  • S_J_PS_J_P Posts: 908
    Try googling "Ridley Tiger" & "BB" or "Ridley Tiger" & "Bottom Bracket", there's a whole host of hits, but in native Dutch, it may help!
  • slowrunner
    you do know the BB is Left-hand thread drive side?

    Italian BB are 70mm so its not that.
    French BB is 68mm but rather rare.
  • nicklousenicklouse Posts: 50,675 Lives Here
    slowrunner wrote:
    I brought the frame only and I intend to transfer my current components on it. So I have no BB or cranket to refer to.

    My current bike fited with Shimano XT crankset (external cup 68mm British/ISO) and I just couldn't screw it in, seem like the thread doesn't fit. I searh on the internet and found that there are few standard in bottom bracket threading, like British/ISO, Italian and French. I need your advice how to determine which BB standard is used in the Ridley frame.

    Thanks.

    you know you have a left hand thread one one side.


    bb02.jpg
    Drive side (right side) cup direction.

    MTB dont use italian BBs

    what fits in what

    http://www.sheldonbrown.com/bbsize.html

    scroll down.

    how to fit a BB
    http://www.parktool.com/repair/readhowto.asp?id=94
    and
    http://www.parktool.com/repair/readhowto.asp?id=95
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • I brought the frame to my local bike shop, the mechanic commented the thread look unusual fine compared to the 68mm British/ISO standard and he did measure the diameter, it is confirmed to be 68mm. He tried to install the BB external cup (68mm British/ISO), it just able to went it two to three turns and it felt tight so he stopped to force it in.

    So it could be either Swiss, French or fine thread 68mm British/ISO but unfortunately the bike shop do not have the Swiss or French standard BB to try it.

    Shall I told the mechanic to force the 68mm British/ISO to install on the frame? Please suggest what I should do

    Thanks for your advice.
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