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Rust Never Sleeps


Page Turner

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...I thought I wold post some photos of an interesting repaint I'm doing currently.

I've had the bike for years now, and enjoy riding it enough that it made the cut for a repaint, which is somewhat laborious in nature, and very time consuming.

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Anyway, it had one of those Mavic 616 "free floating" bottom brackets in it when I got it.  They're supposed to last forever. This one was still working well, but the paint is pretty bad on this bike. It had already been restored once by Cycle Art, and the guy let his brother "use" it for a while, and the brother kind of trashed it.  I knew it had been less than well cared for, for a time, but I bought it anyway because I liked the guy, and it was too big for him.  I think he used the money to fly to Portugal.  But I digress.  Here is what it looked like upon disassembly of the BB.

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So I blocked the crank shell holes and the bottle boss holes, filled it 3/4 or halfway up with Evapo Rust (as seen on TV) and this was the result after hanging for a couple of days:1072859890_Cooperrestoration2001.thumb.JPG.2fbadb5b799ce757cc8e95f13d05aef6.JPG1149123058_Cooperrestoration2002.thumb.JPG.90dd51eedd126e6106d95ea6b9c418d0.JPG1294383395_RonCooperrepaint3002.thumb.JPG.7691d090f54ed9e22b1b32e2f40e2b21.JPG1759793399_RonCooperrepaint3003.thumb.JPG.8458e3a010b68335d1b903314867b6c9.JPG1718210873_RonCooperrepaint3004.thumb.JPG.8fb4e237eb71fc2083ca6b018c6a0819.JPG

 

I blew it dry with compressed air, and then oiled the interior with a corrosion protection oil similar to frame saver (but cheaper and sold at Home Depot)

Here is what the stuff I drained out of it looked like after two days. (It's normally a clear, yellowish green tinged liquid)

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1 hour ago, Razors Edge said:

Rust??? On a bike? In 2018? Huh????

:D

Tom

...whatever genius designed that Mavic "lasts forever" bottom bracket unit, they put the fucker in an aluminum alloy shell ( to save weight) and it's  a slip fit like a seat post in the shell, so you've got bare aluminum in contact with steel, in the wettest spot on the bicycle.  To make it even more prone to galvanic corrosion (and to cost more and save more weight) they made the rings that lock it in place from titanium.  So there's a lot of potential between those guys on the galvanic scale.  Here is what it looks like, extracted and buffed up on a wire wheel a little. 

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I doubt I'll use it again, but I didn't want to do a destructive removal with a hammer. You can see where the aluminum sacrificed itself, like the zincs on a big ship.

The spindle will work with some other cranks, but this one was, I think, specific to a Mavic Starfish crank, and I don't have one of those It was marginal with that Shimano crank, but it rode OK and never came loose.

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5 hours ago, donkpow said:

What will you use to chase the BB threads?

...the simplest solution, which I hope will work, is to use a piloted set of standard taps. Then just run a standard sealed unit better quality cartridge in there with JIS ends.

If the threads don' re-cut to where that appears secure, next step up is to ream it a tiny bit and tap it Italian.  I have both those sets of BB taps from back when Cyclus tools were pretty cheap out of England and Holland.

 

The co-op has them, too. They bought the deluxe Park version.  But I hardly ever go in there any more, because the open hours are a PIA. For someone without those tools, Velo Orange makes and sells a threadless unit now for just such an application. But it's not cheap, just a little bit cheaper than buying a set of BB taps.

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...as anticipated, chasing the existing threads did little to encourage a sense of secure threading for a BB installation.

So this is the result of re-cutting the threads to Italian dimensions. As an added bonus, this seems to have eliminated most of the 45* chamfered edge that was cut to install that Mavic.

 

 

Ron Cooper restoration 4 001.JPG

Ron Cooper restoration 4 003.JPG

Ron Cooper restoration 4 004.JPG

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53 minutes ago, donkpow said:

You don't run into problems with the counter thread (right twist) of the right side?

...not as long as you use piloted taps. Start the adjustable cup side first, then mate the pilot shaft and start the drive side after the other one is well seated.

It's usually better to ream off the old threads before you tap, but in this case, they were so eroded that I just tapped right over top of them. Use approved thread cutting technique (plenty of cutting oil and back it out a half every turn or two to let the chips drop out.)

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