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Old 08-01-12, 01:37 PM   #1
Tandem Tom
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Bottom Bracket-English or Italian?

I am looking at some frames and some have English and some Italian threads. Are there pros and cons at work here? I am a newbie.
BTW one comment I heard from the LBS was that the Italian thread items could be more $$.
Thanks!
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Old 08-01-12, 01:39 PM   #2
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Italian threads aren't as common and could unscrew itself without thread locker. Go with English.
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Old 08-01-12, 01:49 PM   #3
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could unscrew itself without thread locker.
Has anyone who installed one seen it happen? I struggle to understand how rolling balls can unscrew anything halfway tight.

IMO the only reason you need to avoid Italian-threaded frames is the BBs are like 1 in 50, if that.
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Old 08-01-12, 02:07 PM   #4
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Has anyone who installed one seen it happen? I struggle to understand how rolling balls can unscrew anything halfway tight.

IMO the only reason you need to avoid Italian-threaded frames is the BBs are like 1 in 50, if that.
The process through which the threads loosen is called precession It is the same reason left pedals are reverse threaded.
Precession works similar to how a spirograph toy works - when a smaller cylinder rolls around the inside of a larger cylinder, it is actually turning the opposite direction to the rolling relative to the larger cylinder. Int he case of a bottom bracket, the larger cylinder is the bottom braket shell and the smaller is the bottom brakcet cups. Pedalling forces will tend to make the cups roll around the bottom braket shell. THe shell remains stationary and the cups rotate in the reverse direction of pedalling. English BBs have reverse threaded right hand cups so the reulting action of the cup turing opposite the pedalling will tend to tighten both cups. On Italian (and other obsolete both-sides-right-hand-threaded BB styles) the right hand cup can loosen itself off. I would expect if the BB shell is made with excessive clearance and the cup has too loose a fit this will be more likely. On properly made Italian threaded BBs, if the cups are properly torqued then loosenign off is unlikely.

Very few modern frames are made with Italian threading. More modern road bikes come with some style of pressed-in bearings than Italian threads these days.

Last edited by DCB0; 08-01-12 at 02:12 PM. Reason: added link to spirograph and precession
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Old 08-01-12, 02:15 PM   #5
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I never used threadlocker on my Italian bb shells and never had problems. How many people have struggled to get a bb cup out of a frame? I think a lot more than have seen a problem with a loosening cup.
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Old 08-01-12, 02:32 PM   #6
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I never used threadlocker on my Italian bb shells and never had problems. How many people have struggled to get a bb cup out of a frame? I think a lot more than have seen a problem with a loosening cup.
Come to work one day this winter and see how much penetrating oil, torching, and cursing it takes to remove a stuck BB cup from a rental bike that has been ridden on the beach and along salt marshes.

I have worked on a few Italian BB that have unscrewed themselves. One on a Schwinn 564 that eventually got a threadless BB installed to finally fix the problem. (Not really threadless, but a cartridge that threaded back onto itself rather then into the BB shell)
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Old 08-01-12, 04:03 PM   #7
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My 2006 Colnago C-50 Campy Italian bottom bracket did partially unscrew itself shortly after I had built the bike up from a frame and fork. I had not used a torque wrench on the BB. After torquing it to specs it has never loosened again.
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Old 08-01-12, 05:24 PM   #8
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I had one back out, some medium strength loctite fixed it.

- Joel
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Old 08-01-12, 05:53 PM   #9
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My 2006 Colnago C-50 Campy Italian bottom bracket did partially unscrew itself shortly after I had built the bike up from a frame and fork. I had not used a torque wrench on the BB. After torquing it to specs it has never loosened again.
+1. Not a Colnago but an older Olmo; the drive side backed out on a ride (had to stop every 5 miles to hand tighten it). When I finally arrived home and re-greased it, I gave it my best with 14" BB tool and it's never been a problem since;be advised it is common practice to leave the fixed cup in place when re- greasing Italian loose ball BB to save wear and tear on the cup and frame.

BTW: I couldn't figure out how to attach a torque wrench; how is this done?

Last edited by onespeedbiker; 08-02-12 at 10:46 AM.
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Old 08-01-12, 08:15 PM   #10
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My 2006 Colnago C-50 Campy Italian bottom bracket did partially unscrew itself shortly after I had built the bike up from a frame and fork. I had not used a torque wrench on the BB. After torquing it to specs it has never loosened again.
That's the "secret" of installing an Italian bb properly. Unfortunately, unless it is torqued adequately, it will back out as you and other posters have experienced.
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Old 08-02-12, 04:41 AM   #11
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I'll see a couple of loose Italian bottom bracket cartridge bearings come loose each year, while wrenching about a dozen small cycling events. One thing is that you need two splined removal tools for Italian BB installation, whereas you can get by with a single one for English. BTW, I cannot remember the last time I saw a traditional cup/cone Italian BB come loose.
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