From the Bike Shop: Repair Oddities

salty BB.jpg

If you’ve been a mechanic for a long while, you’ll have come across some odd things. Take this Campagnolo Record bottom bracket. We pulled it out of a Seven titanium road frame that had been owned in Florida. Titanium is well-known for its corrosion-resistance, but that doesn’t mean the parts will survive. I don’t know how much exposure to a saltwater environment is necessary to create this much galvanic corrosion of the aluminium cups, but one of the cups came out of the frame in powdery-white, misshapen fragments. I’m from Florida, and I haven’t seen this happen before.

Though one time while living in Florida I was overhauling a English 3sp bike, and the BB turned out to be a spider’s nest. No sir, I did not care for that.



11 Comments

While sea salt (and road salt) is nasty stuff, spiders are just pure evil.

Someone needs to tell that BB owner that the margarita salt goes on the rim of the glass, NOT inside the frame!

That much salt had to have come from a dip in the ocean…which reminds me of a friend who accidentally knocked his bike off the boat and into the Intracoastal Waterway.  He never bothered to drain the frame afterwards, and about two years later the frame virtually disintegrated from the inside out…powdery rust galore.  In some places, the chrome plating was the only thing holding the frame together!

If I happened into powdery white chunks from Florida, my first suspect would be neither sea salt nor galvanic corrosion.

Just sayin’.

Salty Bottom Bracket sounds like a companion to Alice B Toeclips.

Looks like standard tri-dork stuff to me.  Triathletes are notorious amongst shop rats for the horrible condition of their bikes.  These are the same people who the day before a race (if you’re lucky) want a full overhaul.  You’ll find all sorts of nasty stuff like that on a tri-geeks rig.

“I don’t know how much exposure to a saltwater environment is necessary to create this much galvanic corrosion of the aluminium cups, but one of the cups came out of the frame in powdery-white, misshapen fragments. I’m from Florida, and I haven’t seen this happen before.”

As someone with marine engineering, the answer is ‘not much’. Remember, they’re in Florida. If they’re near the coast, chances are that their rain has at least some salt in it. It only takes a tiny bit of saltwater to initiate galvanic corrosion, which will continue even after the exposure to the saltwater is finished. Looking at that BB, I’m guessing it was exposed to seawater approximately six months ago, and it was probably dry on grease in the packing when it was.

+1 to Raiyn’s comment. I had a wrench tell me once that he could take any given Tri/TT bike and tell immediately whether the rider was a triathlete or cyclist based on how trashed the drivetrain and bearings were.

Though one time while living in Florida I was overhauling a English 3sp bike, and the BB turned out to be a spider’s nest. No sir, I did not care for that.

I once hosted a colony of ants in a freewheel hub.

Spider’s nest - heh.  Good one.  My favorite was watching as one of my mechanics pulled the BB out of an old 3 speed (common theme?) and noticed what looked like a string dangling down from the seat tube.  He tugged on it, removing what it was attached to, which proved to be: a dessicated mouse carcass!  It took him a moment to see what he had in his hand, and his experssion was priceless. Fortunately, we don’t see that too often.  Val

I suspect the corrosion you see in the picture is caused by direct contact between the titanium frame and the bb material (presumably steel).

I can’t even imagine how much force it took to remove that bad boy…

titanium frame, aluminium cups, ti spindle. the guys in the shop thought that the white was salt, but I’m sure it’s mainly aluminium oxide.  in Florida, my family used to own a storm shutter company (to keep you neighbors lawnchairs from flying through your windows during storm season).  never seen that kind of corrosion in a bb, but I’ve seen plenty of it on awnings and shutters. 

the rest of the bike had barely any wear on it.

we have a 3’ cheater bar for bb extractions like this.  even then, the force broke one the cups apart.

Couldn’t this corrosion be cause simply by the owner’s sweat—void of salty sea water or salted rain?

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