Just realized my Bianchi BB lugged shell has huge weld at the seat tube insert! Safe?
 

First of all if I'm doing something wrong forgive me for being a noobie. There are two questions I have. The first is high priority.
I purchased this bike about a month ago and got a great deal on it. I got such a good deal on it, I overlooked this huge weld around where my seat tube inserts to the BB shell. I obviously saw the large black painted area, but attributed it to someone covering up chipping paint caused by sweat corrosion, etc. I've been building the groupset on it and saw this when I was changing my crank. I'm well invested into this project as it will be my commuter/weekend/everything bike. I'd love to keep riding it if this thing is safe. Any thoughts/advice?

Secondly, I just bought a nice late 80s/early 90s campagnolo chorus crank to replace my other campy chorus crank... the new one has a nice stamp on it and its shiny.. I knew when I was buying it that I would probably need a longer spindle. The only problem is, I am having a hard time determining what spindle length I need.

Thanks in advance
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First off, good thing you spotted the weld now, rather than later, or never. The weld though looks pretty good, I mean, that's some solid skill at work there. I'd wager it's fixing a crack and doing a good job of it, but, if it's fixing rust or something then I'd want to check it out from the inside when you change the BB spindle and see what's going on. You can always chemically strip that area since you're just removing the black, not the original paint, no real loss there.

Agree; the weld looks solid. A failure at the bottom of the seat tube is unlikely to be catastrophic; it'll just feel like the bottom bracket is adjusted too loose. Ride on and keep an eye on it for cracks developing.

For the spindle I'd find the part numbers for both the BB and the cranks you purchased and try to find them on Velobase. You may be able to see what the standard equipment is for them and compare. You'll need to measure the spindle with calipers just to know what you're starting with. I bet if you found the cranks on Velobase it would give you some options for BB lengths that came equipped with those arms. Looking at that, knowing what you'd have I'd find the next longest recommended length or more, depending on how off you think you are. I enjoy the educated guesswork =)

This is a very common failure point on steel frames -- been there, done that with my 1971 Nishiki Competition, on which the seat tube lug broke away from the BB shell after 20 years and 40k miles of use. This is definitely NOT a safety issue -- I merely heard a creak on every turn of the crank and felt a little slop through the pedals.

Okay great! That's great advice about stripping the area because whoever did the paint job sucks at taping off. Also, it's great to know that you all think it's a good weld job because I wouldn't have been able to tell.

Stellar idea, I wish I had a set of calipers. The crank has a 93 on its underside and I wonder if that's more than likely the year. If so the crank was produced in the same year as this bike, so I can possible get away with just finding the original bottom bracket with spindle and see how it matches up to my take off in size and then just search for that spindle. All great advice! Thanks once again!

Am I seeing cracks in the left chain stay lug? And I big crack developing in the BB shell itself to the left of the seat tube?

http://www.bikeforums.net/attachment...8&d=1438459714

We don't know if the weld is a good one or not, whether the right welding rod was used or to what degree brass contaminated the weld.

I would not expect this to last terribly long relative to the original bb shell, but this bike has some serious mileage under it's belt in all likelihood.

Seeing how it's a mig weld, the contamination was likely pretty negligible.

Regarding the cracks you think you're seeing. I could simply be the paint cracking from the flex in the steel frame. At least that's what I hope it is. That would really suck if the seller sold you a bike with cracks in it. I'd think he'd be afraid of a brick through the window or something. People do suck, but hopefully this is a good weld and everything is solid. I think you need to blast the paint off of this big mess, pull the BB and see what's going on inside and out.

Fortunately for you Bianchi frame sets sell for very cheap. Around our parts the bike coops and vintage cycling resellers can't get rid of their older vintage frame sets, except very cheaply. I think its amazing that people buy low end road bikes from the LBS when they could have a Dura-Ace/Ultegra Bianchi, Klein, Cannondale, or Trek bikes for half the price, and with good wheels. I'd rather have a good bike than a new bike with cheap plastic components.

I think what you are seeing is residual paint that's lifted off of the metal rather than cracks. Scrape off the paint is those area and look for signs of cracks in the bare metal.

I'm jaded because I worked around high qrality welding in the aerospace, medical, food processing, semiconductor manufacturing and other high tech areas as well as heavy construction welding.

For those who may be unfamiliar with the terminology, metal welding almost always refers to heating a part or parts to high enough temperature that the material melts in the weld zone. A filler material made of a similar metal is heated to the molten stage and added to build up the welded area or fill gaps. The melting point of steel is ~1370°C (2500°F) but welding temperatures get hotter.

It can be done with a lot of different technologies including an oxi-acetlyne torch or various methods using electro-arc resistance welding with and electrical arc to provide the heat.

Brazing or soldering on the other hand uses metal alloys that melt at lower temperatures that the base metal and microscopically embed in the surfaces of the part or parts to create a strong bond when the brazing metal cools. Brass or bronze brazing alloys used on bike frames have a melting temperature of ~1500°F to ~1800°F.

Welding thin wall steel parts is tricky because it's easy to overheat the material and burn through the tubing.

The weld in question looks REALLY cobby. It appears to have been done with electo-arc "stick" welding rather than more sophisticated TIG (Tungsten Inert Gas) welding. Most welded bike frames are assembled with TIG welding.

As @dddd mentioned, it's easy for the lower meting temperature brass to contaminate the steel weld. My welding instructors would have beat me soundly about the head and shoulders with a bundle of welding rods if I ever did a weld like the one on this BB...

That said, the kludged repair may last longer than the rest of the bike... On the other hand, why did it crack in the first place? Overheating during the initial brazing is the usual culprit. Or... it could have been a defective BB shell to start off with.

Now that I've offended everyone with my OCD aesthetics...


The only spec that I could find for a late 80's early 90's Chorus BB length is 111mm. I'm running Campy 111mm wide Veloce sealed bearing BBs with Chorus cranks on a number of bikes. They're inexpensive and so far have worked well.

They come with British (68mm wide) or Italian (70mm wide) threads with steel cups and a solid axle, steel cups with a hollow axle and aluminum cups with a hollow axle.

Note 1: Once a crank arm has been installed on a BB spindle and used, the aluminum deforms and all of the crap about ISO, JIS and so on is just that! If it fits, IT WORKS!

Note 2: The Brits call lugless brazed frames "bronze welded".... The US and the UK, two peoples divided by a common language!

verktyg :troll:

Chas.

Verktyg, very close to my perception of things shown.
So far it is holding together, if it lets go again then a problem but one where the rider will live to tell the tale.
Kind of surprised the owner did not realize the repair, oddball two tone is a dead giveaway.

OTOH, this weld is on the thicker, bulge-formed bottom bracket shell. As others have mentioned, this is a fairly common failure point on such shells, usually a result of the seat tube not fully extending into the socket in the shell. This means the crack, and subsequent weld are below the level of brass penetration so contamination shouldn't be an issue.

I think the "cracks" are actually the edge of the original paint, where it was removed to do the repair. They should have feathered the edges, but they also should have found a better touch up color than black, :lol:.,,,,BD

Thank you for educating me, haha. Your comment was very helpful. I think I am going to go on riding it bc all in all I have no more than $135 into the frameset.
As for the crank and spindle issue, I measured my current BB at 102mm in length and concur with you about the one needed being 111mm as referenced by
VeloBase.com - Component: Campagnolo FC-01CH, Chorus.

So I googled to see if any were for sale and came across this listing:
Campagnolo Chorus Bottom Bracket Square Taper 68 mm x 112 mm English Thread | eBay

Could this guy be wrong? I have not seen any of this era bottom brackets in 112mm. It's possible that it is 111mm. In any case, if it is 112, would it be satisfactory? Also, is it a good idea to change just the spindle and leave the same cups since my current BB is Record?

The original 102mm wide BB in your frame is for later model Chorus crankset.

111mm is the "correct" spindle length for the earlier Chorus cranks.

112mm vs 111mm spindle length can be a matter of manufacturing tolerances... or the seller didn't or couldn't measure it correctly.

Contrary to urban myth and wishful thinking, bottom bracket components and crank arms used wide manufacturing tolerances and were never that accurate!

THESE WERE BICYCLE PARTS... NOT SWISS WATCH MOVEMENTS! (I'm yelling at the true believers in the cycling world, not you)

http://bikeforums.net/attachment.php...hmentid=468653

A few years back I was putting together a cheap SS beater bike for wet weather riding. After ~40 years of messing around with BBs I decided to do a quick and dirty documentation of my trials and errors on this project:

https://www.flickr.com/photos/282672...7627678462359/

Read the info below the photos for details...

I accurately measured over 40 BB spindles and BB cartridges plus BB cups and a lot of crank arms. These included Phil Wood, Campy, Stronglight, Shimano, Suntour, TA, Avocet and other brands.

http://bikeforums.net/attachment.php...hmentid=468655

The Phil Wood BBs were the only ones that repeatedly met the published specs. All of the others were consistently way out of spec.

"Make to print, beat to fit, paint to hide!"

That said, plus or minus 1mm or 2mm difference in the spindle length isn't going to matter to anyone who isn't OCD (Obsessive Compulsive Disorder).

Once the soft aluminum crank arms have been tightened onto the spindle, the internal squares distort to fit the taper.. It's a force fit! After that, all the bunk about ISO, JIS and so on is just that... See my flicker album in the link above.

Crank arms that have been frequently removed and replaced or ones that have been run loose can be scrap... They will fit too far onto the spindle:

http://bikeforums.net/attachment.php...hmentid=468654

There are a number of the Campy 111mm Chorus BB cartridges currently listed on eBay:

http://www.ebay.com/sch/Bottom-Brack...and=Campagnolo

You will need a BB tool to install the cartridge. Make sure to thoroughly clean out the threads in the BB shell and the cartridge - even if you take it to a LBS to install (especially if you take it to a shop).

Park makes a tool that sells for ~$9.00

BBT-5/FR-11

http://bikeforums.net/attachment.php...hmentid=468668

verktyg retrotrogrouch :troll:

Chas.

What @CHAS sez. I typically follow his advice. I often get into trouble when I don't.

Sometimes I'll post something and he'll come in and sternly correct me. It's like being admonished by your high school science teacher. You sit and take your medicine, because you know he's right.