Bicycle Mechanics - Italian bottom bracket question

I'm in the process of rebuilding a 1988 Bertoni road bike and am a little stuck with the upgrade of the bottom bracket. I was told I could put in a Shimano Octalink cassette BB to go with a new Octalink crankset as long as I got Italian threading (70mm). I got the new Italian BB, but it doesn't seem to want to thread into the shell :confused: . Anyone have any experience like this or suggestions?? Any help appreciated, thanks!!

Hmm?, Suggestions- ( some may be too obvious)

Do some comparitive measurements with width and inside diameter of English or Italian BBs you may have on hand to determine if it is really Italian ( I've run into frames with Italian names and English BBs) Italians are wider on both dimensions

If it is the left hand side you're having trouble with, thread it right handed ( Italian BBs are theaded right hand on BOTH sides)
Did you receive the "right " BB?

Have your LBS "chase" (and "face "( see below)) the threads on the BB shell

Grease the threads on both the bb and bb shell, ( Shimano may suggest Silicone Seal as they did in years past on their Cartridge bbs for Mtn bikes)

Check for thread damage and use a jewelers file to correct, or go to LBS ( as above)

Have your LBS install it, a very good idea if your BB shell hasn't been "faced" ( a special tool is used to cut or re-cut (chase) the bb threads and to machine the outside edges of the bb to make sure they are completely parallel and paint free) with many of the newer bbs this is not as critical as it once was because the outside edges of the shell are no longer used as part of the mounting surfaces. ( I'm not familiar enough with your bb to know if this is the case)

Ride Far
Pat

Originally posted by pat5319
Hmm?, Suggestions- ( some may be too obvious)

Do some comparitive measurements with width and inside diameter of English or Italian BBs you may have on hand to determine if it is really Italian ( I've run into frames with Italian names and English BBs) Italians are wider on both dimensions

If it is the left hand side you're having trouble with, thread it right handed ( Italian BBs are theaded right hand on BOTH sides)

Both left and right side BB cups thread clockwise to tighten, so I'm assuming that would make it Italian (as also says my LBS).

It seems that the threads are fine since the old BB cups thread in and out very smoothly. Even though the threads on the original cups seem to be the same size and count as on the new Shimano BB cartridge, my fear is that Bertoni used some non-standard size or threading. Have you ever heard of that happening?

(Original BB spindle is stamped "Ofmega", so I'm asuming the cups are also Ofmega.)

My Bianchi has Ofmega cups, and they are Italian-threaded. I can almost guarantee yours are Italian-standard, as well. (Italian BBs are really weird: 36mm diameter, 24 threads per inch, and Whitworth groove angle. Not even Sheldon can tell me how they ended up with these dimensions! Perhaps Shimano cut their cup grooves at 60 degrees instead of 55, in which case you should be able to force a fit, as long as you promise never to convert back to the other thread pitch. This was also the reason we were told that a strong rider should never to put an Italian-threaded freewheel on an English-threaded hub, or vice-versa.)

By the way, that extra mm of diameter in Italian BB shells guarantees that any other BB cups, French, Swiss, or English, all of which are 35mm in diameter, will slide in and out without seriously engaging the threads at all.

I had a problem similar to yours with my (English-threaded) Austrian bike after I got it back from repainting (see classic/vintage thread for a couple of pictures of the new paint job). The (self-tightening/left-threaded) fixed cup had put up one hellacious fight on the way out and did likewise on the way back in, so a bit of thread-chasing was in order.

It is not unusual to have to fight the cups in on the new cartridge BBs. But if you feel uncomfortable doing it, have the LBS do it. There may be a burr in a thread that is causing a problem. You'll be able to tell this by removing the cartridge and inspecting the threads for damage when you feel unusual resistance. If you can't clear it up by running the original cup in and out a few times with a lubricant, have it tapped to clean the threads. If there is no thread damage, you should be able to work it in with out a worry. Just tighten , remove, inspect and retighten as often as necessary to avoid any damage.

Bertoni's were an Italian import by Ben Lawee Imports in CA. They would be pretty standard stuff with regards to threads.

Andare l'acquisto tutti i componenti italiani per quella bicicletta.

Originally posted by don d.
It is not unusual to have to fight the cups in on the new cartridge BBs. But if you feel uncomfortable doing it, have the LBS do it. There may be a burr in a thread that is causing a problem. You'll be able to tell this by removing the cartridge and inspecting the threads for damage when you feel unusual resistance. If you can't clear it up by running the original cup in and out a few times with a lubricant, have it tapped to clean the threads.

Thanks all for the enlightening insights! I completely stripped the frame down, cleaned the BB shell well, and am entrusting the installation to my LBS. They say that after retapping the shell they're confident it will go in just fine. I'll update in a couple of days. Thanks again :) !!

Just a thought: was the BB shell perhaps ovalized along the way? That would certainly make installing any BB hard.

Originally posted by Dave Stohler
Just a thought: was the BB shell perhaps ovalized along the way? That would certainly make installing any BB hard.

Interesting thought Dave. I'm guessing not, since the original cups spin in and out very smoothly. My LBS though, says that even though the original cups spin in and out okay, it's till possible the threads need to be cleaned up and prepped for the Shimano threading. Maybe that's the "chasing and facing" Pat suggested above. I'll see in a couple of days how it all came out. Thanks :) !