Bicycle Mechanics - 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.

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.

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.

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.

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?

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

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

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.

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. :)

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.

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.

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.

Because you like the pain....

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?

??? I always see them at the same price as English for the same BB. What are you on?

Only place I see them, is ebay, and there they sell for 3 to 6 times as much as I can get an ISO BB:


http://cgi.ebay.com/Shimano-Dura-Ace-7800-7801-7803-HT2-BB-Cups-Italian_W0QQitemZ320107747542QQihZ011QQcategoryZ56195QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/FSA-MegaExo-Italian-Road-BB-Cupset-New_W0QQitemZ320105520634QQihZ011QQcategoryZ56195QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/Shimano-Ultegra-6600-6603-HT2-BB-Cups-Italian-New_W0QQitemZ320105490563QQihZ011QQcategoryZ56195QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/Shimano-105-Octalink-BB-ITALIAN-Triple-NIB_W0QQitemZ190106403466QQihZ009QQcategoryZ56195QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/Dura-Ace-Triple-Bottom-Bracket-Italian-BB-7703-NEW_W0QQitemZ250106648519QQihZ015QQcategoryZ56195QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/Shimano-07-Dura-Ace-BB-SM-FC-7800-ITALIAN-bottom-braket_W0QQitemZ280089008797QQihZ018QQcategoryZ56195QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/Dura-Ace-7703-BB-Bottom-Bracket-Italian-Trpl-New-in-Box_W0QQitemZ330109165727QQihZ014QQcategoryZ56195QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/BB-cup-set-Stronglight-Competition-Italian_W0QQitemZ140092133768QQihZ004QQcategoryZ56197QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/CAMPAGNOLO-RECORD-07-ULTRA-TORQUE-BB-CUPS-ITALIAN_W0QQitemZ270109200584QQihZ017QQcategoryZ56195QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Strangely, square taper italian BBs seem very rare.

they still make threadless bb you know.

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.

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

Al

Spending the time/money to modify a frame just to save a couple bucks on a bottom bracket is questionable.