MarkusForest

Hello all

OK so i own a 1990 Colnago Super (custom). It came with DuraAce group. I have recently came across a first gen Campy Chorus group (all but the BB). So I bought an Italian Chorus BB online. I am now trying to install it. But after about 1.5 turns with my hand it will not go further. Use a tool and it take alot of force to move another turn. First I though I bought the wrong BB thinking maybe it was English. I check the old DA BB and it says 36x24t, just like my new campy one. I cleaned and lubbed the threads. Quetion, should I keep turning in hopes of tightening it? Is this normal?

Comments and commenters will not be held responsible for anything here. This is all me. Just looking for someone who experienced the same.







Many thanks
Markus

Katiesmalls

If it were me, and will be very shortly according to USPS, I would keep tightening. Those threads were cut to have a cup removed very few times in a frame lifetime. Have someone hold the frame even resistance, so you don't bend the tubes in the repair stand and tighten it. In my opinion which is worth zero, as long as they are threading in straight keep going. Just in my experience switching Bottom bracket fixed cups is always an " ADVENTURE " especially Japan to Italian.

MarkusForest

Just doesn't seem right. Stopped work for the evening. Maybe gain new perceptive tomorrow.

wrk101

Never, ever, force parts that aren't threading in by hand. Frame is too nice to risk damage.

Threads should have been designed for routine removal for service.

Spaghetti Legs 

I have a circa 1996 C40 with a dodgy bottom bracket shell and I always worry about cross threading. The older Campy bottom brackets have shallower cups/threading than the newer cartridge bearings. Not sure if older Dura Ace is the same way. Consider resistance from essentially unused threads?

That being said, if I was sure the bearing was threaded in straight and I met significant resistance using decent leverage with a wrench, I would be nervous too. If all the threads look clean, it might be worth a trip to the LBS to get the shell tapped and faced.

jiangshi

Have it chased and faced. Best $40 you'll ever spend.

Dan Burkhart 

Yup. Might have to make a few calls to find somebody with Italian taps, make that PILOTED Italian taps, but if I found even a hint of resistance screwing in a BB, I would not proceed without this step.

repechage

Yes, but before that step... The threads on the new cartridge bottom bracket do not look clean in my book. They should be bright and shiny all the way down to the root of the thread valley, maybe there is grease in the thread valleys but I want to know it is only my grease, not grease and dirt. This also applies to the bottom bracket shell. Do that cleaning and see if it goes any farther in. If you still have resistance, then have the threads chased. Note though that the cartridge has more threads than the previous cup, spindle assembly, so the thread cutting and cleaning also has to be to the necessary depth.

Oh yes, try the new cups separately, before you try them as a left and right assembly. Bottom bracket shells are not always threaded concentric and parallel. The Campagnolo tool and some others will correct this as the two taps mate, some taps are without this feature.

Dan Burkhart 

Which is why I emphasized piloted.

JohnDThompson 

+1 this.

John E

If the cups are aluminum and the frame is steel, you will not damage the frame, but the chase-and-face recommendation makes a lot of sense to me, as well. You could also use the lockring to clean the threads on both cups.

Narhay

Are you sure you're threading the right cup into the right side?

I may have done the wrong cup into the wrong side once and it was exactly as you describe after a turn or so.

kingfishr

The original photograph shows the right side and label of the BB

JohnDThompson 

With Italian thread it shouldn't matter. Chasing the threads ought to cure the problem.

MarkusForest

Ok fantastic. A few pieces of advice i picked up here:

1 - do a better job cleaning
2 - run lock ring through BB to help clear out the valleys.
3 - bring to LBS to be chased and faced (must look this up for full description of what this is)

Thank you all for this advice. Once again, this community has shown patience and respect for a relative newbie.

From so-very-cold (-20c) Ottawa
Markus

repechage

I think that is a pretty good read on it. I would inquire with the local bike shop as to if they have the tools, Italian threadings are becoming archaic, typical tool sets would be by Campagnolo, cyclus or Park. VAR made them too but also made taps without a centering pilot. "Chasing" the threads is essentially running in a tap into the existing threaded bore and that corrects flaws in the threads, different and less aggressive than doing a complete tapping as there are threads there. However in this case as the cartridge unit has longer threaded segments than the cups you removed, I would that that unit with you to make sure they go deep enough to clear and possibly create enough threading for it. Who wants to make two trips in the described weather?

rootboy 

I don't see that you mentioned it, MF, but….did you buy that BB new? Or used. I agree that the threads don't look exactly hunky-dory.
If bought used, is it possible someone might have threaded that into an English BB at one time? I don't know about these things, just asking.
The threads look sort of like they may have been deformed slightly. Like the peaks are rounded over a bit. Just ruminating here.

jiangshi

That's not gonna happen, different diameters.

rootboy 

Ah, right. Wouldn't even start in an English BB, would it?
Thanks.

(I have mainly French stuff )

79pmooney

I was told years ago that Italian threads, esp Campy, were cut and that the Japanese threads were often "rolled"; that the Italian threads had a "V" shape and the Japanese threads had radiuses at both top and bottom. Hence to screw a Japanese part onto an Italian frame (or vice versa), on had to force the radius onto the Italian thread tops that first screwing. I have done this many times, to replace Japanese cones with Campy on hubs for example. (Is this the difference between JIS and ISO?) (The rolled threads are better, stronger threads as the grain of the metal is deformed much like in a cold worked part.)

Before I did this with an Italian Frame and Japanese BB, I would make dead sure that the threads were indeed identical except for the profile as you will have to turn the BB with a substantial wrench and you will never feel mis- or cross-threading.

Ben

rgver

Check the thread by comparing it to the DA by matching the threads together, they should sit nicely inside each other with no visible air gap between them, in other words use the DA as a sort of thread gauge. As suggested earlier clean, clean and clean, thread on the lockring, even try threading on the DA lockring.

repechage

As Campagnolo hub axles are 26 tpi... Having them match Japanese parts I would not expect.
On the bottom bracket parts, thre does appear to be a variation between the manufacturers.

randyjawa 

Important rule of thumb - don't force stuff!

Clean the threads on both the bottom bracket housing and the bottom bracket. Use a good thread lubricant and then start threading. Clean and try again. Sooner or later, unless there are other issues, the threads will fit and do so with minimal effort. If not...

Take the frame to a bike shop. It is possible that the threads, in the BB housing, have been damaged. Ask the boys/girls at the shop to chase the bottom bracket housing threads, then try the new bottom bracket fit. Should be all good by then, hopefully.

In closing, another rule of thumb - don't force stuff!

jiangshi

I thought it was tighten it until it strips, then back off a quarter of a turn!

miamijim

I just went through this with a French bottom bracket. You probably cross threaded Campy cup.


1. Re-install the Shimano BB...Does the fixed cup thread in all the way? If it does use the DA lock ring to clean up the threads on the Campy cups.
2. Does the Campy cartridge install ok? If the cartridge installs OK then install it first, maybe thread it in 2/3 then install the loose cup. Doing it this way allow the cartridge to act as a guide for the loose cup.