Colnago Master Bottom Bracket Issue (NYC)
 

I have a late 80's/early 90's Colnago Master Piu with 1st gen 8speed dura ace. Recently, my cranks have started shifting laterally, about 2-3mm. I checked/tightened the chainrings so that isn't the problem. I have taken it to four different bike shops in Manhattan and they have all concluded that it is a bottom bracket issue but none have a square taper Italian BB and 3/4 shops tell me they do not know when they can get one. The last one was not confident when they would have it in and asked for me to check-in a week from now.

I remember relying on this forum and Sheldon Brown's (RIP) site back when I built the bike in 2009. I consulted Sheldon Brown's site again and just wanted to see if people could confirm that I need a 70mm x 113mm bottom bracket to match with my 8-speed groupset?
https://sheldonbrown.com/bbsize.html#dura

Would this work: https://www.ebay.com/itm/SHIMANO-BOT...8AAOxy9tpR84Fz

My plan was to originally upgrade my entire drivetrain to SRAM Force 22 and a new wheelset once Covid-19 died down and prices came back down but i just got laid off on Friday so that isn't an option anymore.

As an aside, are there any folks in the NYC area who have a spare Italian bottom bracket kicking around that i can buy or a spot/set up for me to attempt the BB change myself?

If I recall correctly about the rules of the forum, I have included a pic of my bike.
https://cimg4.ibsrv.net/gimg/bikefor...0368304a46.jpg

Check the backside of a crankarm for a model number. If you have FC-7400 or FC-7402 the BB you linked should work per Sheldon's chart.

If all else fails, you could put a Phil Wood BB in there :)

Remove the drive side cup. put teflon tape on the treads, smear some grease on the shell of the BB, and crank it down real tight! Italian threaded BB can do this if not tightened properly.

Thanks! 7400 crank arms so I might go ahead and get the BB and hope a store can put it together.

I was hoping it was just a loose BB but multiple shops thought it was a broken BB. I would love to explore the loose BB option but like most folks living in NYC, I don't have access to any equipment beyond basic servicing tools.

Weird that a bike shop can’t source an Italian thread BB in a timely fashion. That BB you linked is a UN26 which is bottom of the line. In your shoes I would splurge an extra $10 if you can to go with the UN55. They usually have them for around $25 shipped on Amazon. Good reliable BB.

As far as the problem you describe it sounds like the BB might have backed out on the drive side but that is an unusual problem if the BB has been in place for a long time. If it’s gonna happen, IME, it’s usually within the first 100 miles or so after an install. If it is otherwise working fine, I’d be at a loss to explain why it’s doing that without some kind of god awful noises coming out when you pedal.

Thanks. Good to know. I was unsure on the BB hierachy. I'll try and source a UN55 in the 70mm x 130mm but haven't had much luck yet. I was shocked too that most LBS in Manhattan did not have an Italian threaded square taper or couldn't order but my own search so far has proven difficult which i guess confirms their statements.

Not a god awful sound, but definitely a noticeable skipping sound as if the crank wasn't catching at each pedal-stroke. Definitely makes more sound during climbs. As you said, I installed the BB ages ago (back in 2009 in undergrad) and this is a relatively new issue.

2-3mm lateral shift means either a loose cup (DS cup in pic appears properly seated) or some serioisly worn out ball bearings. If it’s bearings there will be more damage to the spindle.
As Spago said,unusual for a cup to back out later in life.
Literally ANY italian threaded 113-115 mm Shimano or Shimano compatible BB will interface just fine with that crankset. UN55 is better and there are more italian threaded ones out there (checked eBay and they are out there for like $30 plus shipping)
Velo Orange sells one that I think is rebranded Tange and they are also good.
Spend more or less, your choice. Personally, I would buy the needed tools and do it myself if my LBS was unable or backed up.

Have you checked with Larry's Freewheeling on 110th? You'd need to speak with Larry himself, the young folks are nice but have no idea what you're talking about. He may have something in his stash.

Thanks. I'll explore this option. Checked Velo Orange and unfortunately they do not have anything Italian threaded larger than 110mm. Out of curiosity, how are both the 130mm and 150mm compatible. 2cm extra seems surprising, or am I assuming I'll need to readjust the front derailleur?

A forum member, Jethin has mentioned he may have a BB and might be able to help me replace it.

I'll check this store out tomorrow and ask for Larry - hopefully he's in. It is relatively close to me. I checked out Velo NYC, Bicycle Renaissance, Sid's, and Zen bikes.

Good luck, let us know. I'm in the neighborhood too.

Yep, happy to help if I can, though I’m a bit of a ride from you. And I second Larry’s. Anyway I’m sure we’ll get you fixed up one way or another. ;)

If you need to borrow BB tools, and can live in or can travel to the Upper West Side (Columbia Univ. area) and will take social distancing as seriously as I do, then I may be able to help -- that is, I could do without the tools for a day when you've got all the stuff together to accomplish this.

One thing that you might want to look out for is: Sutherland's Manual says that, like vintage Campagnolo BB spindles, Dura-Ace 7400 spindles are asymmetrical: the drive side projects farther from the shell and/or bearings than the non-drive side does, for a spindle that's nominally 113 wide (standard road double). However, most garden-variety (leaving out, say, high-end products like Phil Wood cartridge bearing BBs are symmetrical -- both ends are the same length. Thus, you may need to get a longer cartridge BB to have the same chainline that you did with a loose-ball BB.

https://cimg5.ibsrv.net/gimg/bikefor...316d29c353.png
You can see from the above that the asymmetry is fairly significant -- the left side (A) is 8 mm shorter than the right. Assuming that the dimension B is centered on the BB shell, I think if one were to take the B and C dimensions, and even things up, an equivalent symmetrical spindle that would give the same chain line would be 121 mm, 8 mm longer than the 113 Dura-Ace original.

Additionally, there's the characterization by Sutherland's that the closest taper "type" is "Campy", while most garden-variety cartridge bearing units have a JIS taper. Campy is very close, but JIS is "technically" a bit stubbier on the end, meaning that you might find that a JIS 121 mm spindle would be too long; but my guess is, just a few mm too long, not 8 mm.

A third variable here is how worn (leading to oversize, and sitting closer to the BB shell than it did originally) the female socket of your drive-side crank arm is.

Within reason, you can make a shorter spindle achieve your ideal chainline by adding a thin but hard shim of good quality under the flange of the drive-side (fixed) cup, padding it out. But again, that's going to help for maybe 1-2 mm. If you were using a Phil Wood, whose design has some built-in adjustability, then maybe a couple more? Dunno myself, you'd have to check with them.

Upshot: you might need to fit a cartridge bearing BB by a bit of trial-and-error to achieve the right chainline for your bike. Once you have one, if it doesn't seem to be actually working in the length department, then at least you'll have a good model for buying the second one with more assurance of success.
Disclaimer: I don't know much at all about Dura-Ace stuff; (or Phil Wood stuff) I just find this subject of tapers interesting, and have a copy of Sutherland's for reference. YMMV.
Sorry, but BBs can be complicated, even though they look deceptively simple. Thank your lucky stars that you don't have one of those new-fangled contraptions, which are probably even worse.

Finally, do you realize that your profile says "Seattle" and not NYC?

Thanks for the Larry's recommendation! Stopped by there this morning. Larry was out but one of his employees had a look, diagnosed it as a loose cup issue ( i should have included more pics for you guys) and tightened the cups/bb. Only issue is apparently I've now developed a front derailleur issue. I've toyed around with limiter screws in addition to the cable but the derailleur is refusing to shift out of my high gear - not really a problem I guess as I rarely ever used the low gear - and a problem I'll leave till I'm working again.


Thank you for the kind offer - i actually live in the UWS too. As I mentioned above, larry's shop seems to have fixed the BB issue - at least for now. I appreciate you offering your tools out but I'm sure I would have botched the job even with multiple tutorials.

I know my profile says Seattle. Definitely due for a change. Its leftover from when I started the account and I was in undergrad. I've actually lived in three cities since but always intended to move back to Seattle hence the lack of change.

You're welcome, and if you need a hand with anything else bike-related that I can provide, don't hesitate to reach out.
Front derailleurs are easy compared to bottom brackets, seems to me. Limit stop to limit stop, so long as it's set up parallel to the big ring, cage close to it, and not bent. Maybe not, with brifters though, or a Shimano product (known for idiosyncrasies, incompatibilities and unceasing but unnecessary change).
About Seattle: I understand completely -- my son lives in Seattle, it's a great city, we visited regularly before the pandemic, and if I weren't a confirmed NYC-dweller with some roots now that keep us here, we'd think about moving there too.

I would encourage you to take Charles up on his offer, make sure the BB doesn't need an overhaul, may not but should be inspected after loosening issue to make sure.

He can probably help with the shifting issue as well, you are in a place to get this sorted and with help the outlay will be minimal for long term success. ;)

Cool, glad that's handled. All three of us in the UWS. If only group rides were a thing...and it was less than 90 degrees out.

I took a worn-out cone nut into a super-fancy NYC bike shop a few months ago hoping they could match it. They sent me to the back where I met this kid who couldn't have been a day older than 20--gorgeous kid, looked like a model. He took one look at it, looked me straight in the eye, and said: "Oh, you're going need a new wheel."

Sorry for the OT rant. There are also a lot of good bike shops here in NYC. R & A Cycles out here in Brooklyn seems to specialize in fancy Italian bikes like yours. They also seem very knowledgeable and helpful, and while you're there you can ogle all the $$$ bikes and frames hanging from the walls and ceiling.

This is not even funny to me, that probably works on the majority of customers and you can be sure that the resident C+V guy scoops up all the stuff that gets "upgraded" to modern crap.

Don't get me wrong, new stuff suits the modern crowd and that's fine but the disposable, threadless, cartridge cookie cutter crap has rendered skilled techs to parts replacers with no real respect for the skills that built their trade, instant gratification rules the day. Too bad. :crash:

Can you see which part is moving laterally?
If the cranks are moving on the axle, you might need new cranks more than a new BB.
If the axle is moving laterally you could try to take it apart. Older BBs sometimes have exchangeable bearings.

Good luck!

Yeah, it was hard to know, in this case, whether he wanted to sell me a new wheel or whether he genuinely believed that I needed one. In any case, another shop was able to match the nut and the wheel is still working great on my main road bike--not even a very old bicycle; I was psyched to discover that it didn't have sealed bearings in the first place. (I would post a picture of it, but most of you would be horrified.)