RacerX Posted March 15, 2011 Posted March 15, 2011 I had a rather bizarre Argus - towards the top of Wynberg hill (Bishop's Court) I could not get the chain on the big ring. I looked down and noticed that I could see some of the thread of my drive-side BB cup peeking out of the BB shell - the BB was spontaneously unscrewing itself, moving the crank to the right! The stomp up the hill must have got it loose and soon after my left crank was hard up against the BB shell (the left cup had moved inboard too, moving the whole BB to the right) and I could not pedal without badly scoring the left crank arm. I managed to limp to the end of the M3 where there was a "mechanic" next to the road. His crank puller was so stripped that he could not get my cranks off, so I walked off, thinking it was the end of my ride (the race part of the ride having ended on Wynberg hill). Anyway, long story short, a good Samaritan called Mark took me home in his bakkie where I fixed the bike and then he took me back to where I exited the course to finish the ride (it was my 21st Argus and I wanted that medal!). Thanks Mark! My bike is a lovingly-maintained (by me) 1998 Colnago Technos (steel - the real thing ) with an Italian thread Campag Chorus BB, also circa 1998. I last removed the BB when I had the frame touched up about three years ago. I always install BBs and cranks nice and tight. So the BB has been in there for three years without trouble, and nearly ten years before that. If you didn't know, Italian BBs have a right-hand thread on the drive side, as opposed to a left-hand drive-side thread of an English BB that is standard on most non-Italian frames. I had a look at what Sheldon Brown had to say about Italian BBs, and I quote: "Prone to problems due to the right threaded fixed cup,which tends to unscrew itself in use."http://sheldonbrown.com/cribsheet-bottombrackets.html The English BB standard is superior because the left-hand threaded drive-side cup is tightened by the pedalling action (as is the right-hand threaded non-drive cup on both It and En BBs). Pedals have opposite threads for the same reason. So, the real reason for my post is to warn any other owners of pretty Italian bikes with silly wrongly-threaded drive-side BB cups to pull your drive-side crank off now and then and tighten that sucker up! Also, any advice on what lube/other sticky stuff to use other than grease to help prevent this from happening again would be appreciated.
Tiny K Posted March 16, 2011 Posted March 16, 2011 Locktite - either the paste or the liquid (702 I think)
javadude Posted March 16, 2011 Posted March 16, 2011 I see even the Italian frame builders are going to English thread BB's, although this may be due to most of the frames being built in Taiwan nowadays. I say stock up on some Italian thread BB's while you still can.
javadude Posted March 16, 2011 Posted March 16, 2011 what exactly is locktite ? Its kind of like a glue liquid that you apply to threads to make sure things don't unscrew themselves. Not a permanent bond though because you can still use a bit of force to unscrew your bolt or whatever.
LeTurbo Posted March 16, 2011 Posted March 16, 2011 what exactly is locktite ? Get it from a car repair place like Midas. You know how sometimes, when you take a bolt off something, there's blue residue in the threads? That's Loctite - it just "glues" threads together without making nuts and bolts impossible to remove. Though admittedly I haven't used it for aout 20 years ....
Slowbee Posted March 16, 2011 Posted March 16, 2011 aaahhhhh, thanks Velo, thanks LeTurbo. does it only work on threaded stuff ? (sorry RacerX, bit of a hijack)
LeTurbo Posted March 16, 2011 Posted March 16, 2011 Slowbee, I know it's also recommendeed for the old "square taper" crankarms - basically anything that can vibrate or work its way loose
Slowbee Posted March 16, 2011 Posted March 16, 2011 Slowbee, I know it's also recommendeed for the old "square taper" crankarms - basically anything that can vibrate or work its way loose
Cyclocross Posted March 16, 2011 Posted March 16, 2011 Same loosening happened to me on an old Bianchi during a race many years ago after I had had it resprayed. Regular finger re-tightening didn't work and eventually after many stops was loaned a large pair of plumbers vice grips by a parent following the race. It worked but not the lightest tool to carry in your pocket!Permanent fix was to boot the old cup and cone bb and replace it with a cartridge bb which came pre-loaded with locktite on the threads.
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