Bicycle Mechanics - Italian bottom bracket

Okay,

I have been eyeing Italian frames, and love the heritage and the paintwork, but i finally found out what is different about their bottom brackets.

Originally i thought that the thread was a different pitch and they were just a tad wider, but the big deal is that they are threaded the same on both sides :(

that means that on one side the pressure of cranking the pedals when riding will try to loosen the BB cup!!!

So, is this a big deal or something where if the cup is installed properly it will never come loose.

If so, what is properly, torqued? red locktite? teflon pipe tape? grease?

Basically it is an OBVIOUSLY inferior design and I don't want to spend all my coin on a new frame to end up futzing with a BB that wont stay tight. So, will i regret it or is it a non-issue?

thanks,

Steve

If one cup that loosens in the direction of crank rotation is bad, then both doing so must be twice as bad! As in English bottom brackets!

Originally posted by Hot Pepper
If one cup that loosens in the direction of crank rotation is bad, then both doing so must be twice as bad! As in English bottom brackets!

No, english bottom brackets are so they will both tighten when pedaling, yes?

At least every single report i've read of an Italian BB coming loose it is the right one that loosens. And on an english BB its the right one that is reverse threaded.

If you read my statement, I said one side will loosen with pedaling, not which side would do so or any detail on exactly how that occurs. My guess is that the bearings involved reverse the thrust so that, counter intuitively, the cups will tend to be loosened in the opposite direction of the crank rotation. However, i know none of this for sure, only that the right cup tends to loosen up on an italian BB.

thanks,

Steve

Steve........don't even waste your time worrying about thing like that......they would have addressed this problem decades ago if their design was inferior.
So how's your stock portfolio?

There's a reason most bikes have reverse-threaded right hand cups, so they don't unthread. Seems kinda dumb to me to use a design that is proven to be inferior, no matter how nice the rest of the frame is.

Ummm.......so if this is a major flaw in the design, why does the cycling industry continue to market & sell the product, and above all, a good portion of the last TdF riders use them?

I have a couple of bikes with French thread, that have the same issue as you describe. The right side of the BB needs to be tightened to a very high torque, for it not to work itself loose. I didn't torque the BB enough once, it loosened up while I was riding. I then kept re-tightening the BB by hand every 300 meters or so, till I got to the shop with the proper tools, where I tightened the BB very hard - and never had a problem since. With English thread, you'll not have the loosening problem while you are riding, but it can be really difficult to remove the BB after a long time of riding, if it ever needs removal. The English thread keeps tightening the right side of the BB as you ride. There are many cries for help in this forum, where people are trying to remove the right side of the BB on older bikes without special tools.

Originally posted by George
Ummm.......so if this is a major flaw in the design, why does the cycling industry continue to market & sell the product, and above all, a good portion of the last TdF riders use them?

1) It is a bit cheaper for manufacturers to use clockwise threads exclusively. Originally, French and Italian frame builders presumably did not want to pay royalties on the British patent for self-tightening BB cups.
2) This is not a fatal flaw, because the problem can be addressed with heavy torque and/or Loc-Tite.
3) I need to think this one through a bit further, but modern cartridge bottom brackets may have less tendency to self-loosen than their traditional cousins.
4) Several Italian manufacturers actually have switched over to English/ISO threading.
5) The French must have considered it a problem, because at least Peugeot and Motobecane switched over from French to the even less-common Swiss threading sometime between 1975 and 1980.
6) I have experienced fixed cup loosening on my first Bianchi and on one of my old Peugeots. Conversely, it was extremely difficult to remove the original English-threaded fixed cup from my Capo.
7) The two benefits of French or Italian threading are:
a) You can always remove the fixed cup.
b) If you install adjustable cups on both sides of the BB, you can fine-tune your chainline.

English and Swiss bottom brackets are engineered correctly, with a self-tightening, anticlockwise-threaded fixed cup. (I know this seems counter-intuitive, but consider pedals, which are also self-tightening, even though the right side is clockwise-threaded. The epicyclic action of the ball bearings generates a torque opposite the direction of rotation. If we used plain bushings instead of ball bearings, everything would be very intuitively obvious, and right-side pedals would have to be left-threaded.)

In a metric world, I am still amazed/amused that British BB threading won out over Swiss! :)

I had un-threading on my Concorde Italian BB. until I finally torqued it hard and used a little blue loc-tite. Since then no problem. I had the setup with two adjustable cups and never really cinched them in tight enough. Instead I would tighten the rings to the shell quite hard. As mentioned above, the reason for the two adjustable cups is to allow for chainline adjustment, which is going to be of use to me in converting it to fixed in the future. I would thread my right side adjustable cup in to where I wanted it to be relative to the centre of my cog set, and then snug the left side to the BB. I should have applied much more torque when doing this, and then tightened the right side again. When this is done, it still allows me to undo both sides to clean and grease the BB. shell without too much effort.

It is interesting though that it is still in use. As John E. states, it is a flaw, but not a fatal one. I wouldn't discount buying a great Italian bike for that reason, but would prefer it were otherwise.

Very interesting posts on this thread. Very informed members must be the reason.

Thanks, John E............I learn something new here every day!

Here's a report of a right side, left hand threaded, bottom bracket cup loosening up fer ya, it happened to me personally.

Best reference on the web is @ http://www.sheldonbrown.com/harris/bottombrackets.html
This year I had to replace the BB cups and spindle on my 79 French racer and Harris Cyclery in West Newton, MA was the only place in the country I could have found one. If you get a chance to visit their shop, check also the all campy vintages they have on display..