SurferRosa

We've all seen this concerning square taper standards:


The above section could be more clear if it simply read that Campagnolo switched to ISO around 1994. And new cartridge bb's with the JIS taper actually offer the better fit for vintage Campagnolo cranksets over their ISO counterparts.

dddd

I don't find that ISO taper is a problem with vintage campag cranks, at least not in terms of the engagement.
At worst, on a really stretched crankarm, one might have to grind a mm off of a spindle end.

But the bigger issue is whether you will find an ISO bb with the right length AND offset to work with your old cranks on your particular frame.

I'll add that Sugino Mighty and Suntour Superbe tapers are identical in width to ISO tapers as found on Campagnolo cartridge bottom brackets.

And I agree that ISO is closest to old French tapers compared to old Campag or especially compared to JIS (which is a bit more than .2mm thicker than ISO).

I tend not to worry about "taper length" as it has never been an issue for me (If the crankarm touches the inside flare where the taper ends, it typically happens after significant press-fit has already been achieved).

One more thing.
At most, the difference in engagement depth/travel due to mixing the biggest JIS taper with the smallest ISO taper will be <3mm on each side.
Phil used a hybrid JIS/Old-Campag taper that split the difference, so affected chainline by at most about 1mm this way or that. I have one here, measures 12.8mm instead of 12.7mm (old Campag) or 12.9mm (JIS).

For those with a caliper, comparisons between different tapers can be made as shown (JIS Dura Ace 7400 spindle shown).
Also, by locking the caliper jaws at say 13mm, one can measure how far up the taper that two different spindle tapers allow the caliper jaws to slide up the taper.
For numerically accurate (versus comparative) measurements, be sure to check/calibrate the caliper's measurement using a new ball bearing. Simply zeroing a cheap or worn caliper may result in undersized measurements.

merziac

I have never worried about it one way or the other, mix and match, trial and error, yes it fits, yes it works, done.

As a professional mechanic I can't even begin to count the number of times I have ignored the books, testing, processes, etc when they did not work for me.

Many times it was the same as the BB conundrum, dig in, tear it apart, find the problem that the testing wouldn't find or devise a workarond that solved it.

jonwvara 

What an empiricist! Shocking.

John E

The older the equipment, the more that tends to be true. Minor revisions sneak in, and incompatibilities result, even when the "official" word says everything should play nicely together.

Salamandrine 

Yeah, when you have a bunch of repairs in front of you, there isn't time to argue about theoretical standards, which BTW didn't used to exist when I was a mechanic, they were not applicable to BB spindles.

You simply made sure that that picture in Sutherlands was complied with: end of spindle not bottomed out, spindle end not too far from the inside flat of crankarm, and lastly, the crank is not bottoming out inside by running out of spindle flat.

IME production variation was pretty significant, more than people realize.

I appreciate the measuring advice. If I have time this weekend, maybe I'll measure old campy vs old stronglight vs modern JIS. As I recall when I did it before, both campy and stronglight were in between. Stronglight closer to JIS.

squirtdad

there are also a bunch of other niggling little details depending on the year like asymmetrical spindles. in my limited experience with a campy clone ofmega (which adds even more confusion, but the 1984 model was pretty much identical to campy) it ended up being simpler to find the proper BB vs try to get a cartridge to work (and i had a really good LBS try with a miche cartridge)

SurferRosa

That's great, and I appreciate your post. But here's the problem. When someone reads this ...


... and he's looking for a new cartridge bb for a "vintage" Campy crankset, he needn't shop for what was just recommended by Sheldon. He should be looking for a JIS one. They actually fit a little bit better than ISO, are more plentiful, less expensive, and easier to procure.

miamijim

What makes it confusing is, and correct me I'm worng, that both ISO and JIS have the taper angle. The childs toy, with the colored rings, ISO is like the top rings while JIS is the bottom rings.

robertorolfo

I was just about to ask why Gipiemme, Ofmega and Miche were left off the list. All ISO?

SurferRosa

I didn't include everything he wrote on that webpage. He does discuss Ofmega.

https://www.sheldonbrown.com/bbtaper.html

dddd

Depends on what you mean by "fit".

The Campag and ISO spindles have much wider flats, i.e. flats that extend much further out toward the corners where torque is best transmitted with lower contact force!

So for hard use, I believe that the ISO and old Campag and euro spindles are or should be friendlier to the arm's square tapers.

I wish that I knew why JIS introduced the narrower flats(?).

I at 145lbs do use JIS bb spindles with Mighty and Stronglight 91 cranks on a couple of bikes.

SurferRosa

I mean a best "match," as discussed on this page (among others I've recently run across):

https://www.classiclightweights.co.u...bracket-axles/

I wish I knew that to be true. I don't know why this isn't more simple. There's no reason for the confusion. Too much misinformation, starting with that page from Sheldon Brown.

merziac

I think this is a common pitfall when seemingly good info is in short supply. I also think it was probably more sound back in the day when these things were new(er) and it may have actually mattered in practice but really only did on paper, who knows.

There are times when you have to make a stand and where you are actually standing will influence that greatly, Sheldon was standing right in the middle of it so there he was.

I have always thought it would be great if maybe Jobst, Ritchey, Merz, Zinn or many others would have publicly drilled down on this as well.

But anybody that disagreed with Campy or Sheldon would not have fared well, especially back in the day.

Sheldon was probably going off the party line from Campy mainly and we know how that goes when they want theirs to be special/better/just plain pita, etc.

I think it is simple, that's why I do it my way, when it doesn't work I adapt based on the runup of the problem and see if I can solve it.

Not disparaging either of the greats Campy or Sheldon, love them both and am glad they came but trying to underscore the need and ability to think outside the box or party line when necessary.

Salamandrine 

Possibly they were thinking that it would reduce the stress riser of the sharp corner in the square cutout of the crank arms. I really don't know though. Could have been cost savings. Who knows. Just spitballing.

dddd

What I do notice about JIS spindles is that most appear to not be machined, like net forged shape, without the machining marks seemingly always found on ISO and old Euro spindles (with some lower-cost exceptions to be sure).
This has me thinking that the narrower taper flats look to produced using lower-cost methods.
Consider for example that the Mighty and Superbe tapers were always used only on the higher-tier model cranksets.
It could be that the cast crankarms, having much thicker sections about the hole, would not so easily deflect outward from the more-leveraged stresses imposed by narrower JIS taper flats. I wish that I knew more about how the various quality-levels of spindles were produced, for a clue as to why narrower taper flats would be chosen for the JIS spindles.
Note also that certain JIS spindles like 74xx Dura Ace apear fully machined and with wider flats!
And that lower-cost Euro spindles (made for UO9's and the like with cheap, cast Strongligh TS cranks), featured narrower flats more like JIS and showing no machining marks.
So much that I don't know when it comes to spindle manufacturing.

It's just something worth considering, if the usage is to be of relatively high stress. I've had no problems though, no loosening or anything like that, and I ride hard in hilly terrain on mis-matched tapers for some years now.

I'm currently using a symmetric 107mm Shimano bb with my Mity Tour cranks on my Pro-Tour, and am considering trying a symmetric Campagnolo 111mm cartridge bottom bracket for it's ISO taper and for it's lateral adjustability in the bb shell.

BFisher

Similar discussion here. Post #10 may shed some light (or not?).

Kabuki12

I actually measured a Japanese BB spindle versus a Campy spindle on my optical comparator and found the taper to be identical but the Japanese spindle was .0025” per side larger. I wanted to put a Campy NR crank on my Kabuki to replace the SR Apex unit. I indicated it in on my universal tool grinding machine and ground the spindle to duplicate the Campy spindle(from another bike) and it worked great! Then about a year later I ended up with a Campy NR BB and switched it. It can be done but then I am a tool grinder and have very nice precision grinders so it is an easy fix. I have also Reground the bearing surface with success.

SurferRosa

Nor am I. Sheldon's site taught me most everything. But that little quote about Campy being ISO could be a really easy fix that someone should get to chop, chop.

I mean, who cares about post-'94 ... anything?

<ducks>

JohnDThompson 

FWIW, Sutherland's (4th edition) shows the Campagnolo taper as slightly shorter than ISO:

scarlson 

Ha, this thread came about two months too late for me! That Sheldon thing just f###ed with my s##t too!

I had a Campy Nuovo Record-era BB on my Vitus 979, along with some TopLine cranks, which fit nicely on it. Got a nice Ti BB that I found was ISO. No problem, right? Put it on and did not check how far spindle went in. Crank came loose mid-ride.

I switched to JIS and everything was fine. So I learned two things: TopLine/Grafton/Speed Stick cranks are JIS and so is old Campy.

The funny thing is, now just a few weeks ago a friend comes over with 105 cranks falling off his (French threaded) Vitus 979. Sure enough, they're bottomed out. This one seems cut-and-dried JIS needs JIS situation. I make him buy a $12 JIS spindle and some bearing balls off Ebay to put in, but to get him going in the meantime, I find that the spindle in my collection that keeps the cranks farthest away from bottoming out is an old TA. And I have all sorts of Sugino and Specialized stuff in there too. Weird, right?

The machinist in me wants to agree with Salamandrine. The variation must be fairly large. Considering with a 2-degree taper on each side, differences in width make wild changes in length, so this must make things tricky for manufacturing. Like a 0.1mm change in width results in a 1.4mm change in length, by my calculations, and the forging dies must wear out and make progressively larger spindles over the course of their service lives. And they've got to harden these spindles after all this, which can result in yet another dimensional change depending on the process. What a mess! I'm left thinking it's a wonder that any of the cheaper stuff fits anything else without being precision ground!

Charles Wahl

Given enough use, anything will fit on a JIS stub, no? So that's the way vintage is going, until the universe stops expanding.
Here are some data points taken with a Mitutoyo dial caliper (analog) with no particular calibration history (good enough for cycling):


I found these on an old paper, can't remember when I started down this rabbit hole; within the last couple years I think. I didn't bother to go to two decimal digits, obviously. Maybe I'll continue and finish this one day.

bikingshearer 

Don't forget that Sheldon himself says that on multiple occasions he mixed ISO cranks with JSO tapers and vice versa with nary a problem. Reading his stuff on this subject as a whole makes it clear that he thought mixing and matching will work just fine far more often than not, with a chainline perhaps 3mm off one way or the other, depending on which is ISO and which is JSO.

I do remember that when I first got into cycling c.1973, one never heard any distinction between the tapers. A crank was a crank, a bottom bracket was a bottom bracket. All I recall hearing about at the time was differences in quality (actual or perceived) and nada about taper differences.