The background - I installed a Miche Primato track crankset with its matching Slovakian-made sealed bearing bottom bracket unit on my Mercian Vincitore c.2005 or so. Maybe c.2010 I thought it was the source of a creaking noise, so I acquired a second unit and swapped it out, realized it was my pedals after all, and swapped back in the original cartridge unit using the original aluminum alloy retention cups. Everything worked well for many years and it was a set-it-and-forget-it deal.

Until late last year, when I realized the drive side had unthreaded itself so much that the left crank was rubbing the BB shell. I limped home and discovered the right/drive side cup threads had failed. I attributed it to age and swapped in the pristine, new cup, set that beautiful buttery smooth cartridge unit back in place and declared it done.

Until today, when 40-odd miles later I discovered the new mounting cup doing the same thing. Ugh.


This system uses two separate mounting cups that are separate from the cartridge bearing/spindle unit. Here is what caught my eye - drive side all the way out, left crank rubbing the BB shell.

I discovered the threads were damaged and no longer held the cup firmly in the BB shell.

Meanwhile, the LEFT side had somehow screwed itself deep into the shell. I didn’t see that coming!

Threads are trashed here - AND on the replacement unit I fitted. Ideas?


So, first question - what causes this to suddenly happen after many years of flawless operation?

Second, bigger question - this BB system is the older symmetrical 109 mm ISO type Miche used prior to 2013, when they switched to JIS taper. With this crank I get a pretty much ideal 42 mm chainline.

If I go to a JIS BB, which pretty much everything is now, will a 103 get me close enough? Or should I just say, “Enough,” and replace the crankset with something else with a more normal BB?

First question: What is the threading? Italian? English? Important to know to help with diagnosis
I doubt that ISO vs JIS is a factor

Doh! English/BSC -



And I thought it was 109 but apparently it is 107 mm ….

ISO vs JIS matters for potential replacement if I continue using these cranks.

Strings,
I have a conventional Campy BB laying on my desk that needs to go. 109 spindle length, alloy cups with 3/16th inch bearings. I offered it for sale with no takers, so... gimme a call 812-336-3283 Smiles, MH

My take is that the drive side cup wasn't tightened well enough against the drive side of the bottom bracket shell. Precession is a female dog

Precession should cause the drive cup to rotate in a counterclockwise direction (ie opposite the direction of the crank rotation) - which is why the drive-side BB cup is reverse threaded to start with

I have Phil bottom brackets on a few French and Italian bikes. On those, I not only use Loctite on the threads, but add lock rings on both cups if possible to keep the dang thing where it belongs.

ummm... where's the Lockring on the NDS????

whether miche included one or not.... there SHOULD be a lockring on the NDS, and the DS cup will typically have a SHOULDER that butts up to the frame...

solution: get a better BB assy.that includes a shoulder and lockring.

I have Campag cartridge BBs in both BSC and ITA threads, and while the DS cups are flanged (ie a “shoulder”), the NDS cups don’t have lock rings - they’re just screwed in to the specified torque

If the drive-side cup threads are ruined, this suggests that the cup didn't unscrew but was rather forced out, stripping the alloy threads. If the non-drive side cup has screwed itself further into the BB shell, that cup must have done the pushing - it's not going to get "sucked in" as the drive-side cup moves out. I wonder are we seeing some aggressive non-drive side precession screwing the NDS cup in and forcing the DS cup out? I've never seen this happen before, but how else were the DS threads damaged?

do they migrate like the one imaged?
i always add a lockring if there's room.
there's usually room....

btw... BOTH threaded BBs currently offered by Miche show a SHOULDER on the DS cup..

and look at the image on the BOX the op posted... Shoulder and Lock Ring.

neither Campag BB had room for an NDS lock ring nor was one provided. Nor did they migrate as the BB here appears to have done. But I agree that there there appears to be a lock ring in the package illustration. Maybe the OP can shed some light on whether the BB came with one

i'm wondering where the shoulder on the DS cup went.

i think the solution is to get a new BB with a shoulder and lockring.
also wondering what anti-seize/grease was applied to the BB threads....
and i'd be taking a really close look at the threads in that frame too.
a good reface of the BB might help.

That appears to be the direction forward. The stock Miche Primato BB from that era has no lock rings, nor is there space for them. When fitted to the frame, holding the cartridge in place, the stock mounting cups fit flush within the BB shell -



- not the best photo, but this is how these fit. And until the very end of last year they worked without issue for decades.

That describes what I am seeing. The original alloy drive side cup wobbled loosely in the shell. The replacement cup threaded in smoothly and correctly when I installed it. When I removed it yesterday it was shedding threads and wobbled like a loose tooth.

And the operative word here is current. Trawling online I learned that my cranks and bottom bracket are the first iteration of this crankset - ISO spindle, 135 BCD cranks. I bought this setup c.2005 from the guy who runs/ran Business Cycles, and not for the first time have I regretted letting him talk me into these instead of the TA Alize track crankset with the Axix BB and 130 BCD. Anyway, c.2007 Miche went to 144 BCD on the Primato Pista, and for 2013 they went to a JIS taper on the spindle. I am sure they redesigned the BB along the way to include flanges or lock rings.

Again, no lock rings came with either of the BB sets, nor is there room to fit them. And fwiw, I used Campagnolo bottom brackets on other bikes with zero problems.

It looks like my options are to either spend more than I wish to for a TA Axix 107mm bottom bracket with an ISO taper that fits my current cranks, or to seek out a different crankset that accepts a more easily found JIS bottom bracket. Unless I find a shorter JIS BB that will yield the correct 42mm chainline.

Phil Wood also uses a mounting ring on each side of their cartridge. Phil's installation instructions include:
https://cdn.shopify.com/s/files/1/03...s_V1.2.pdf?354

Perhaps try that to prevent a recurrence of that problem.

Not all cartridge bottom brackets use lockrings, e.g. Phil Wood.

that's the one someone mentioned locktiting in place earlier, correct?
hint, hint.

and it seems the miche BBs have a problem beyond that... the cup threads fail.

conclusion: bottom brackets without lock rings and shoulders are bad ideas... and avoid miche when choosing a new one.

interesting that the box doesn't match the BB that rusty bought... maybe someone else thought a BB with no shoulder or lockring was a bad idea, and swapped in the earlier, discontinued parts....

the shoulder and lock ring help reduce thread loading and wear.
and i'd still like to know what anti-seize or grease was placed on the BB threads before installation.... whatever it was not only prevented seizing, it allowed the cups to continue to move during riding.

I used some sort of grease on the threads when I needed loctite. Still - it held for many years. But thread loading and thread failure happens sooner or later.

In the unlikely event I can find a right hand Miche cup, I’ll clean and de-grease and use blue loctite. But odds are I am looking at replacing the whole BB at the very least.

even miche ended that shoulderless/lock ring-less BB... take that as a sign.
eventually, if you keep using that lousy designed BB, you will also damage your frame.
from what the images show,It already needs refaced.
there are several nice new BB options available.
i wouldn't include Miche in your shopping.
there's good reason they're now a "Hey, don't forget us!" status company
and the "new crankset" on their site is just plain UGLY.
it makes the latest DA/Ultegras look positively gorgeous.

I suspect the thread in the bbkt shell is belled out, my 1979 Holdsworth did the same. As a temporary fix I secured the bottom bracket with epoxy, and used it like that for a couple of years until I had the shell sleeved when the frame was refurbished.

If that's the case, another option would be a threadless cartridge, such as offered by Velo-Orange, YST, and likely others as well. If you want a threaded option, the shell can be reamed and full-depth Italian thread cut for an Italian thread cartridge.

This looks like a job for the Saint Sheldon Pass Around Tool (SSPAT). Chase the threads and install a new BB. A couple of options here in MH's shop, What I think is a Chorus 109 standard BB or an Athena cartridge type at 116. I am not sure about the change in chain line but the 116 is probably long enough for lock rings on both sides. Lemme know, Smiles, MH

That will work if the only issue is that threads needed chasing, But taps, even in a chasing operation, can only remove metal; they can't replace missing metal. If the threads are bodged enough that a cup can't get secure purchase, no amount of chasing will cure that. A threadless cartridge or tapping fresh, full-depth Italian threads (assuming the original thread isn't already Italian) would be the proper fix.

I don't think the BB threads in the shell are damaged. When I checked the left side with a known steel BB cup they worked correctly. When I threaded in the replacement cup on the drive side initially, it felt totally normal. When I removed the drive side cup (both times) it came out along with the fine wire that had been the aluminum threads on the cup. I will obviously confirm things with a STEEL, known drive side cup before hand. But I think what happened is the left side somehow screwed itself in (precession is a new term for me to absorb), and in so doing literally pushed the whole bearing cartridge against the relatively frail threads of the alloy cup until they failed. I suspect that having a left side cup with a lockring and a drive side cup with a flange will resolve this issue once and for all.

FWIW, I double checked the original paperwork from when I ordered the frameset from Mercian - and yes, they chased and faced the shell before shipping it to me.

Mad Honk is sending me some BBs to try, and I will be reporting on the result both in this thread and in a new one I will create.

John and Strings,
Since we know the parts were aluminum I would at least clean the threads with a wire brush before doing any re-assembly. I use these wire attachments on my impact drive and give it a circular motion inside the shell. The bits are about $5 and last for a few uses. It cleans things pretty well. Smiles, MH

Wire rush attachment for impact driver.