Alloy bottom bracket cup + ti frame corrosion

john

The Guv’nor
Admin
Retrobike Rider
Feedback
View
If interested this is what happens when you leave a bottom bracket with alloy cups (it was a un-91) in a titanium frame for 13 or 14 years. Pulled this out of my litespeed saturday night (just before the long mynd ride), as you can imagine it was a right twat to get out. Fortunately a combo of a workstand, massive scaffold bar, some GT-85 and WWF-esque effort shifted it. The non drive cup had corroded pretty badly, a fair bit of it was like powder.

The drive side cup was fine, came out no bother. Not quite sure why, would've installed the bracket with grease / copper grease. Perhaps I forgot on the non-drive, didn't put enough on or the fact it's slightly more exposed than the drive caused the issue.

Almost (but not quite) tempted to go an dig my materials text books out the loft to read up on this.

After a quick clean up the b/b shell looked good as new and the NOS UN-71 very kindly supplied by Robert went in no bother :)
 

Attachments

  • 2013-04-27 19.27.10.jpg
    2013-04-27 19.27.10.jpg
    614.2 KB · Views: 212
  • 2013-04-27 19.27.29.jpg
    2013-04-27 19.27.29.jpg
    655.6 KB · Views: 212
I was going to say galvanic corrosion, but that looks almost more like water has sat in your BB shell at some point?

Glad you got it out though!
 
Thanks for posting.......looks like a drain hole even in Ti would be beneficial. Not bad for 14 years though !
 
Back
Top