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-   -   Complex Colnago bottom bracket issue - Warning! Carbon fiber content. (https://www.bikeforums.net/classic-vintage/1034569-complex-colnago-bottom-bracket-issue-warning-carbon-fiber-content.html)

Spaghetti Legs 10-14-15 03:16 PM

Complex Colnago bottom bracket issue - Warning! Carbon fiber content.
 
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This may not be vintage, but I think definitely classic as it involves my 1996 C40 - first year this was produced. It's been sitting in a box for years due to this problem, but I've gotten the itch to get it back on the road.I think the threads may be worn in the BB shell because when I thread the bottom bracket on the drive side, there's a little wiggle and when it gets to the point of tightening it to the frame the bearing will slip and loosen and I can't get it tight. I took it to the shop, not the LBS as there isn't one that can deal with Italian thread frames, this one is an hour away. The wrench, an older, experienced sounding gent, didn't think there was a save for this and that chasing the threads would not help. I'm currently exploring options for replacing the BB shell, which may be very expensive, if not impossible.

So to my question for you smart folks, or anyone else willing to offer an opinion:

In the meanwhile, I'm messing around and I thread a fixed cup from a 1980's Campy Record bottom bracket and it wiggles a little while threading, just like the Chorus cartridge bracket I tried, but the fixed cup will tighten down, and I can torque it pretty hard without giving way. BTW, I don't think the issue is with the Chorus bracket as I had the same problem with Ultegra and FSA BB's before consigning the frame to "the penalty box". So I'm reconsidering to maybe have the threads chased anyway, gamble the $20 to see if that helps. Option B would be to use the Record loose bearings with the cups that work. I want to put Campy 10 speed double on it, which requires a 102 mm axle. Is there an axle around from the 80's that would fit the bill and work with these cups? Would modern Centaur, which I believe uses a 113 mm axle, work with an old Record BB?

As always, thank you for your attention and advice.

JohnDThompson 10-14-15 07:21 PM

If the cups are loose already, chasing the threads probably won't help (reminds me of the old joke: "I've trimmed it three times already, and it's still too short!"). Probably the easiest option would be a threadless cartridge, but if you're a glutton for punishment, you can try to scare up some oversize cups, which may fix it for you:

http://www.os2.dhs.org/~john/oversize-cups.jpg

poprad 10-15-15 04:17 AM

The only solution I could offer would be to clean the threads on the BB and shell very well with a strong degreaser, then use a thin coating of epoxy on the threads to fix it in place. Obviously a permanent solution, so using the highest quality sealed BB would be required. I'd be willing to do that with an SKF or Phil if it were mine, knowing I'd never get it out again.

miamijim 10-15-15 05:11 AM

If the older cup properly torques down you should be good to go. I think older C Record BB's use a crazy short spindle, you'll have to verify.

iab 10-15-15 06:01 AM


Originally Posted by poprad (Post 18243117)
then use a thin coating of epoxy on the threads to fix it in place.

Or, use Loctite. I think the blue stuff is semi-permanent. Not quite as extreme as some epoxies and typically used on threadless BBs.

RoadGuy 10-15-15 01:14 PM

If you want something that's removable, that fills gaps, doesn't shrink, that does not require heat to remove, and yet will work at least once (or may be twice) if unscrewed, try ShoeGoo spread on the threads.

A weaker chemical solution would be a non-hardening teflon based thread sealant. Permatex sells one that comes in a can with a brush.

Or what about plain old teflon tape?

Thread locking compounds are seldom a good solution when there is a chance that the components will need to be separated at some point.

Spaghetti Legs 10-15-15 06:58 PM

Thanks all.

Right now plan A is a Phil Wood bottom bracket. I have one on the way and if I can get the cups to tighten down decently enough, I'll use some form of thread compound as I think a Phil Wood will last longer than the amount of miles I'll put on this bike (along with all my others) for the rest of my life. If it doesn't work I have a couple of bikes that I'll be just as happy to use it on. Plan B will be to figure a way to use the old Record cups. The downside of the cup and cone bracket is that they will require occasional removal for maintenance and I think these bottom bracket threads just need to be left alone.

Meanwhile, still looking for a Precisa or Colnago Flash fork for this baby!

Homebrew01 10-15-15 07:56 PM

I also vote for teflon tape as option 1. No harm in trying.


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