# Italian thread bottom bracket



## Marz (May 14, 2006)

Why is there constant mention made of the undesirability of the italian thread bb? 

I have read here that they come loose easily. How can that be when the right hand side cup, which is the different one to the english thread cup, screws clockwise, which is also the direction of travel of the crank when pedalling.

Call me dumb, but I don't get it. What am I missing here?

Thanks in anticipation.


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## bdaghisallo1 (Sep 25, 2007)

Yes the drive side cup tightens clockwise, the same direction as the pedalling action, but the non-drive side has the same right hand threading (the same as the driveside) which means that the pedalling direction is acting in the direction that loosens the non-drive side cup! On an english threaded bb, the cups have opposite threading so they can't loosen under pedalling.

I once had an italian Ciocc frame with an ita bb. Two times I was riding along and the cranks felt funny. Both times I looked down and the complete bb unit had migrating about 7mm left in the bb shell, meaning that the non-drive cup was hanging outside the frame, and the drive-side cup had threaded so far into the frame that my Campy Record cranks were grazing the bb shell.

The first time I figured I had pooched up the install. The second time I swore, on the spot, that I would never own another frame with an italian threaded bb. Many say that with proper installation and torque you "shouldn't" have problems like this with ita bb's, but with proper installation and torque you WILL NOT have these problems with an english/british threaded bb.


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## Marz (May 14, 2006)

I still don't get it. The non-drive side on an english bb screws the same way as the non-drive side on an italian bb, why doesn't that side screw out on an english?

I can usually understand mechanical concepts but this defeats me.

I have an italian bb on my De Rosa and so far no problems.


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## safetyaverse (Oct 18, 2007)

*I'm not expert, as I have only used an English threaded bottom bracket, but...*

I think the previous post is saying that with an English bottom bracket for any given direction of rotation the cups will either be pushing towards each other, or moving away from each other.

With an Italian threaded bottom bracket in the same situation one cup will be pushing towards the other, and the other cup will be moving away.

I imagine this is what causes the problem.


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## michael desimone (Nov 14, 2007)

l left my octa link ultegra bottom bracket in for 8 years no problems (italian thread)
sounds like 6 of one and half dozen of the other


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## bdaghisallo1 (Sep 25, 2007)

Check out Sheldon Brown's bb database for some more guidance:

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

If he thinks it's not good, then it certainly ain't!!! Do some more searching and you will find many tales similar to mine.

If you never have any problems then count yourself lucky. You will be among the very few!


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## wim (Feb 28, 2005)

Marz said:


> Why is there constant mention made of the undesirability of the italian thread bb?
> 
> I have read here that they come loose easily. How can that be when the right hand side cup, which is the different one to the english thread cup, screws clockwise, which is also the direction of travel of the crank when pedalling.
> 
> ...


Things sometimes come loose because of what's called precession. Precession means that a part can rotate itself loose *opposite* of the rotating stress direction, not in the direction your intuition tells you. A good example of intuition being wrong is when some people look at the left-hand pedal threading and conclude that those ignorant 19th century engineers didn't know what they were doing. They did.

Rotating stresses at the bottom bracket are more complex. In very simplified terms, rotating stresses at the bottom bracket are not as constant and less severe than they are at the pedal. There's less of a chance that precession will loosen the right-hand cup, so some designers felt that a left-hand thread wasn't needed. That's true, but only if the right-hand-right-threaded bottom bracket cup is torqued very tightly into the frame shell.


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## Guest (Nov 23, 2007)

bdaghisallo1 said:


> Check out Sheldon Brown's bb database for some more guidance:
> 
> http://www.sheldonbrown.com/bbsize.html
> 
> ...


So it is your contention that everyone who has ever ridden an Italian or Belgian made bike has suffered problems with the bottom bracket?

This is nonsense and although I hate to say it here - Sheldon Brown is not God on these issues.

There is nothing wrong with Italian threaded Bottom brackets, I have many of them and have used them for many years.

If they are properly installed, tightened down and installed with either Loc-Tite or Teflon tape on the threads, they will not come loose.


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## Dave_Stohler (Jan 22, 2004)

toomanybikes said:


> ...................
> 
> This is nonsense and although I hate to say it here - Sheldon Brown is not God on these issues.
> 
> ...


Yes, Sheldon and I once exchanged e-mails on the subject of making a half-step-plus-granny setup on my touring bike (compact 110mm BCD, rings of 52-48 and 32 teeth, 8-speed chain). He told me that it "would not work" because the rings I was using would allow too much space between them to keep the chain from falling in between them and getting stuck. He also had issues about the 32-48 tooth distance from granny to middle ring. I did a little research and found that a Shimano chain had just enough width to prevent said chain falling, and I never had a single problem with the chain going from the granny and middle ring, either way. Sometimes Sheldon is just a blowhard.....

As far as using Loctite, make certain it is the MILD type (222 or 242, nothing stronger). If you use Teflon tape, use as much as you possibly can, since teflon is actually a great lubricant, and just using a single layer might actually make it more likely to back out. Or, you can always use linseed oil, like wheelbuilders do. After a couple of weeks, it gets gummy.


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## bdaghisallo1 (Sep 25, 2007)

Yes, you guys are right, Sheldon Brown is not a god, and is sometimes a blowhard, but he does have a great deal of knowledge on the subject of bicycles. Having experienced problems with ITA bb's, I agree with his assessment of their inherent problems. There must be a good reason why, out of so many differing threading standards, british bb threading is, by far, the dominant standard these days. Sure you can be extra detailed and ensure that your ITA bb won't present any problems, but if you can go to a standard that eliminates those issues from the equation, isn't that the way to go?


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## JCavilia (Sep 12, 2005)

*precession*

To amplify slightly Wim's explanation: If a part is rolling around inside another part, it will rotate on its own axis in the _opposite_ direction from the direction of the larger motion. Draw a large circle on a piece of paper, then move a coin around inside it as if the coin were rolling on the line. The principle will be immediately apparent. 

That's what happens to a left-side pedal, and a right-side bottom bracket cup. English BB's have the right cup reverse-threaded, so it won't tend to loosen. Italian BB's tend to get loose on the right. An Italian BB can be made to work, but the reverse threading on the English minimizes this problem.

Bd, your first post mischaracterized the issue. Whatever happened with your BB, it wasn't the typical Italian BB problem, which involves the right cup backing out.


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## bdaghisallo1 (Sep 25, 2007)

> Bd, your first post mischaracterized the issue. Whatever happened with your BB, it wasn't the typical Italian BB problem, which involves the right cup backing out.


You're right. Now that I think about it, it was the right cup that backed out - this happened some 16 or 17 years ago so my memory is a little off. But it was the typical Ita bb problem. I did research the problem extensively back then, or at least as best I could before the internet.

Been running british ever since and no problems.

Cheers All.


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## Nessism (Feb 6, 2004)

The Italian threading is an inferior design but...works okay as long as the BB is kept tight and/or a thread locking agent is used. Done. Close this thread.


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## Mr. Versatile (Nov 24, 2005)

I agree that you'll have no problems with an Itilian BB if it'e installed correctly. If it ever comes loose ( mine has loosened 3 times in 14 years), just use a little Locktite 222 or 242 as Dave said above. Ta daaa. Problem fixed.


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## the Inbred (Feb 28, 2004)

seems this would have been a bigger issue when the use of loose ball bottom brackets was more common.


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## Kerry Irons (Feb 25, 2002)

*Back in the day*



the Inbred said:


> seems this would have been a bigger issue when the use of loose ball bottom brackets was more common.


It never really was an issue. It happened to me ONCE in 90K miles. The simple conclusion was that I had neglected to tighten the fixed cup sufficiently. Those who have IT cups loosen, now or then, simply did not properly tighten them.


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