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  1. #1
    Sir Fallalot wroomwroomoops's Avatar
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    HOW TO convert Italian to ISO (BSA) BB? (if it's even possible)

    I like a frame that has an italian BB. I want to standardize my equipment, though, and was wondering if italian BBs can be modified to take british (ISO) cartridge BBs.

  2. #2
    Senior Member Retro Grouch's Avatar
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    I don't think that it's going to work, at least not very easily. The Italian BB is a little larger in diameter so there isn't enough metal there to tap it out to English threads.

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    Sir Fallalot wroomwroomoops's Avatar
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    Quote Originally Posted by Retro Grouch
    I don't think that it's going to work, at least not very easily. The Italian BB is a little larger in diameter so there isn't enough metal there to tap it out to English threads.
    Thanks a lot, Grouchy. That's what I was afraid of, myself. Still, I wonder if there's some kind of adapter.

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    * vpiuva's Avatar
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    Not only is there not enough metal, there is no metal. Outside thread measurement of english = 34.8mm (1.37"), inside of Italian is about 35.2mm. Any adapter and machining necessary would cost more than the benefits gained.

  5. #5
    Sir Fallalot wroomwroomoops's Avatar
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    Quote Originally Posted by vpiuva
    Not only is there not enough metal, there is no metal. Outside thread measurement of english = 34.8mm (1.37"), inside of Italian is about 35.2mm. Any adapter and machining necessary would cost more than the benefits gained.

    Yeah, the numbers don't lie.

    damn


    Alternatively: cheap source of BBs (I think they're called "cups" in case of italian BBs)? Anything I have to watch out for, as a purely ISO user, when working with italian BBs?

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    all the major companies still make italian BB's for most cranks out there so there should be no problem finding an Italian BB that will work

  7. #7
    weirdo
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    First you buy a lot of that Alum-alloy from the infomercial...

  8. #8
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    Quote Originally Posted by wroomwroomoops
    Alternatively: cheap source of BBs (I think they're called "cups" in case of italian BBs)? Anything I have to watch out for, as a purely ISO user, when working with italian BBs?
    Yep, Italian bb's are right-hand threaded on both sides. This gives the drive side cup an unfortunate tendency to loosen spontaneously so you have to torque it REAL TIGHT. A lot of mechanics like to use low-strength Locktite when they are installing Italian cups as an added precaution.

  9. #9
    Senior Member DannoXYZ's Avatar
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    What I've done is get an English-threaded BB shell. Mill off about 1mm from the outside. Then bored out the Italian BB by just enough for a tight 0.05mm interference fit. Then use a hydraulic-press to push it in. Tacked a couple spots of brass on the inside to hold it in place. Mill 1mm off both ends and faced the new English-threaded BB.

    If you've got the equipment, it shouldn't take more than 30-minutes.

  10. #10
    Sir Fallalot wroomwroomoops's Avatar
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    Quote Originally Posted by DannoXYZ
    What I've done is get an English-threaded BB shell. Mill off about 1mm from the outside. Then bored out the Italian BB by just enough for a tight 0.05mm interference fit. Then use a hydraulic-press to push it in. Tacked a couple spots of brass on the inside to hold it in place. Mill 1mm off both ends and faced the new English-threaded BB.

    If you've got the equipment, it shouldn't take more than 30-minutes.

    That's how it should be done. I have none of the equipment, though.

  11. #11
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    Quote Originally Posted by DannoXYZ
    What I've done is get an English-threaded BB shell. Mill off about 1mm from the outside. Then bored out the Italian BB by just enough for a tight 0.05mm interference fit. Then use a hydraulic-press to push it in. Tacked a couple spots of brass on the inside to hold it in place. Mill 1mm off both ends and faced the new English-threaded BB.

    If you've got the equipment, it shouldn't take more than 30-minutes.
    WOW, all of this work to avoid using an Italian bottom bracket?

    Or was the Italian bb shell ruined and this was a way of saving the frame? Even so, it's a lot of work and great expense unless you have the tools to do thee work yourself. This had to be a very valuable frame or one with great sentimental value.

  12. #12
    Sir Fallalot wroomwroomoops's Avatar
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    Italian BBs seem awfully expensive, compared to ISO. And yet, the only frames I seem to be interested in lately, are italian. Why oh why do I always do this.

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    Because you like the pain....

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    * vpiuva's Avatar
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    Quote Originally Posted by wroomwroomoops
    Italian BBs seem awfully expensive, compared to ISO. And yet, the only frames I seem to be interested in lately, are italian. Why oh why do I always do this.
    ??? I always see them at the same price as English for the same BB. What are you on?

  15. #15
    Sir Fallalot wroomwroomoops's Avatar
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  16. #16
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    they still make threadless bb you know.

  17. #17
    Senior Member halfspeed's Avatar
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    Shimano and Campy both still make square taper Italian threaded bottom brackets. Campy Veloce if you need iso, Shimano UN54 if you need jis taper. Try aebike.

  18. #18
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    I had no more problems with mine after I torqued it to specs.

    Al

  19. #19
    Senior Member Snordalisk's Avatar
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    Spending the time/money to modify a frame just to save a couple bucks on a bottom bracket is questionable.

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