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French Bikes and JIS taper

Old 12-02-19, 08:27 PM
  #26  
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I picked up this '78 Peugeot with a Stronglight TS, didn't like the appearance of the TS and didn't want to deal with French pedal threads. I had a sort of compact double JIS taper Sugino GT 52/34 laying around. It worked great, on the Stronglight BB, and I liked the look. At the Eroica swap meet, I came across a good deal on a drilled Stronglight 99, a 52/40, so I put that on to preserve the Frenchness a little. No problem on this French bike dealing with JIS taper.

As bought with Stronglight TS.

Interim Sugino JIS taper crank, on original Stronglight BB. Shimano FD replaced broken and missing Simplex FD.

Back to a French Stronglight 99.

Last edited by Slightspeed; 12-02-19 at 08:42 PM.
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Old 12-02-19, 08:34 PM
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Originally Posted by non-fixie View Post
After reading Sheldon's article on the subject way back when, I've never bothered with the difference, and have mixed and matched to my heart's content. So far, I have never run into problems, other than spindles being slightly too long or slightly too short. Trial and error is what I do best.

BTW, I am looking forward to seeing more of that pretty Mercier.
Exactly this, my experience is not expansive by any stretch with this in particular although I have never failed to make it work either, many, many successes.

That being said I do have a substantial amount of practical mechanical experience, bikes, autos professionally, motorcycles, drag racing and more.

Cranks, spindles and BB's are not rocket surgery, the minutiae may seem so but most of this stuff is not new so free for all will usually get it done once you get a feel for it.
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Old 12-02-19, 08:42 PM
  #28  
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Originally Posted by ThermionicScott View Post
Aren't the current Stronglight cranks forged by Sugino?
Either Sugino or Sakae Ringyo, I believe.
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Old 12-03-19, 06:40 AM
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Originally Posted by seypat View Post
For the discussion, Shimano JIS on the left. Stronglight 93 ISO on the right. The are not very close.
On that note, wasn't it determined in another thread (I'm hoping CV-6 remembers it; IIRC, he was part of the discussion) that Stronglight's taper is also deeper on the drive side? If I recall, it was not ascertained whether this was just a deeper cut of the same LH taper, or whether the actual start width is narrower or not.

While I share verktyg 's opinion that a fairly used Stronglight crank can be installed on a JIS spindle if the taper matches up from previous installations, I really wouldn't try to put anything but another Stronglight crank on a Stronglight spindle. The spindle is just too different from the rest - even TA - and I usually find it better to pass them on (or hoard them) for when they're absolutely needed.

Since Germany_chris says Italian equipment can be found easily and cheaply where he is, why not go with a Campagnolo Nuovo Gran Sport or Triomphe crankset with matching French BB? Methinks these bits will be much easier to find in his location, suit the period look (if that's a consideration), and open up the opportunity to use compact gearing:




-Kurt
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Old 12-03-19, 07:08 AM
  #30  
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Here is the Stronglight spindle again. The downside is the longer side. Not much taper on the top, almost square. It is visibly more tapered on the bottom side. Measurements from top to bottom are 32-52-34. the taper length from the end to where the bevel starts(and the wear marks indicate the crank/arm stopped) is about 14mm on the upside and about 18mm on the downside. The size of the square/box that both ends start with appears to be the same size.(to the naked eye with a ruler next to it. Too lazy to go dig out a micrometer) It is under 12mm at the very edge and 12mm where the flat part starts. The taper width starts at 9mm on the upside end and less than 9mm on the bottom side end.

Last edited by seypat; 12-03-19 at 08:04 AM.
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Old 12-03-19, 07:26 AM
  #31  
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Originally Posted by cudak888 View Post
On that note, wasn't it determined in another thread (I'm hoping CV-6 remembers it; IIRC, he was part of the discussion) that Stronglight's taper is also deeper on the drive side? If I recall, it was not ascertained whether this was just a deeper cut of the same LH taper, or whether the actual start width is narrower or not.

While I share verktyg 's opinion that a fairly used Stronglight crank can be installed on a JIS spindle if the taper matches up from previous installations, I really wouldn't try to put anything but another Stronglight crank on a Stronglight spindle. The spindle is just too different from the rest - even TA - and I usually find it better to pass them on (or hoard them) for when they're absolutely needed.

Since Germany_chris says Italian equipment can be found easily and cheaply where he is, why not go with a Campagnolo Nuovo Gran Sport or Triomphe crankset with matching French BB? Methinks these bits will be much easier to find in his location, suit the period look (if that's a consideration), and open up the opportunity to use compact gearing:




-Kurt
That would be the best way to go. What about the RD situation? Would he need to drill out the hanger or can he use a claw and not bother with the hanger hole? As I remember, Velobase might be your site. Great website. The OP can get the info he needs there.
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Old 12-03-19, 07:40 AM
  #32  
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On that note, wasn't it determined in another thread (I'm hoping CV-6 remembers it; IIRC, he was part of the discussion) that Stronglight's taper is also deeper on the drive side? If I recall, it was not ascertained whether this was just a deeper cut of the same LH taper, or whether the actual start width is narrower or not.
I think you are correct I am editing my post with the picture and including the taper length measurements.

Last edited by seypat; 12-03-19 at 07:45 AM.
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Old 12-03-19, 09:05 AM
  #33  
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Originally Posted by cudak888 View Post
On that note, wasn't it determined in another thread (I'm hoping CV-6 remembers it; IIRC, he was part of the discussion) that Stronglight's taper is also deeper on the drive side? If I recall, it was not ascertained whether this was just a deeper cut of the same LH taper, or whether the actual start width is narrower or not.
Stronglight's taper is slightly different on each side, as Sutherland's chart shows:


Source: Sutherland's 4th Edition
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Old 12-03-19, 09:56 AM
  #34  
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That is a good chart- the shop I worked for in 1985 would not buy one... too much $$.
I did get them to buy a Campagnolo tool kit, so my lobbying was not completely lost.
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Old 12-03-19, 05:17 PM
  #35  
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In practice, when a taper "bottomed out" at the back side of the arm, I never had any problems with it, so I don't ever even look at "taper length" other than upon actual installation, noting whether some real bolt tension is realized before the outward flares of the spindle contact the back side of the arm.
The simple difference between JIS and ISO is that the JIS taper is about two-tenths of a millimeter larger across, resulting in about 2.5mm less insertion into the arm.
Thus, JIS spindles should be considered 5mm longer overall (not on each end) than an ISO spindle of the same actual length.
Comparing spindle tapers is easy and informative! One can compare insertion depth of two different tapers by simply locking the caliper at ~13mm and then measuring how far that each different spindle's taper slides between the locked jaws!
I measure spindle end dimensions by putting the caliper jaws flush with a table and then putting the end of the spindle flush with the table, between the jaws, shown below.
This way, the measurement will be at the same 1/8" from the end of the spindle, equal to the thickness of the caliper jaws.

The numbers I get are about 12.7 for ISO and about 12.9 for JIS.
The ISO spindles include Campag cartridge bb's, Sugino Mighty bb's, Suntour Sprint and Superbe bb's, and with old Stronglight bb's being very close as well.

Campag cup-cone bb spindles are in-between, but are significantly closer to ISO than JIS, measuring about 12.78mm in most cases. So not equivalent to JIS in terms of insertion depth.

JIS spindle tapers are claimed by one well-known source to be a copy of old French spindles, but in fact it is the old Sugino Mighty and Superbe tapers which are more of a close copy of old French spindle tapers (such as used on Stronglight 93 and 49d cranks).

Everybody working on bikes should have one of these $10-20 calipers, and spindles should be checked if for no other reason than to verify what I have said here, so that best approaches are used when trying to fit a particular crankset to a desired chainline dimension.

I've used JIS cartridge bb's with old French cranks, but it is essential to consider not only the taper length differences but also the asymmetric offset of the spindles that you will choose from versus the original bb.

For the picture below, actual spindle measurement shown, keeping the measurement away from any rounded edges at the end of some spindles. This is because of the thickness of the jaws forcing the measurement to be that same distance from the end of the spindle.

And again, it is also possible to lock the caliper jaws and then measure with a ruler how far up the taper of two different spindles that the caliper will slide. This will directly compare the insertion depths of the different spindle tapers.




Another piece of advice that I can offer is to keep a few used, but not-so-good-anymore cartridge bb's on hand for test-fit purposes.
So much time can be saved by doing a simple test-fit, and the used bb's typically retain their (steel) taper dimensions much better than (aluminum) crankarms do over perhaps decades of use.

Last edited by dddd; 12-04-19 at 03:19 PM.
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Old 12-03-19, 05:33 PM
  #36  
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Expect a bit of trial and error. Always. Worst that happens is you end up with spare spindles for next project. Do not even think about JIS/ISO. If the chainline is good and the crank tightens up it matters not what spec or proto-spec the crank is.

Completely unclear if the 93 in top photo is to be used or if it is that newer Japanese Stronglight. I can think of no reason whatever not to use a 93. Great crank. Chainrings are not that hard to find. The Stronglight BB that came with it original is one of the best brackets ever and is very easy to find at good prices. And the one that comes with the bike is not known to be bad. Campy will work under a 93. 1990s bracket like Verktyg shows will be easiest. But they are not all the same so don't plan on first time success. Older Nuovo/Gran Sport/Vittoria/Triomphe brackets a 93 will fit too far out . With an old Campag pista spindle it might work but that is too rare a part for this project.

If using the newer Stronglight crank any Sugino or Shimano at hand will work. Better would be to get a Stronglight cartridge made for that crank. They are all over ebay.fr and ebay.de and very cheap. Never much marketed in States.
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Old 12-03-19, 09:26 PM
  #37  
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Originally Posted by seypat View Post
That would be the best way to go. What about the RD situation? Would he need to drill out the hanger or can he use a claw and not bother with the hanger hole? As I remember, Velobase might be your site. Great website. The OP can get the info he needs there.
I only considered the crank; far as I know, the OP's only question.

Honestly, other than concern about wear on those non-hardened aluminum chainrings (and possibly sloppy shifts in comparison to modern ramped rings), I really see no point in changing anything - even for commuting - on this machine. If the game plan requires throwing everything remotely fragile out the window, this was the wrong bike to start with in the first place.

Also, if I had to choose any one part to replace for reliability's sake, it'd be that crack-prone SLJ front derailer (with a Suntour Cyclone/Cyclone Mk.II, if the infinite band diameter suits the tubing). And then I'd ride the wheels off of it...just as is.

Originally Posted by JohnDThompson View Post
Stronglight's taper is slightly different on each side, as Sutherland's chart shows:

Source: Sutherland's 4th Edition
Someday, I'm going to right a great wrong of mine and purchase a copy of that Holy Bicycle Repair Bible for once. Thanks for reminding me of the original source.

Originally Posted by dddd View Post
....[t]he simple difference between JIS and ISO is that the JIS taper is about two-tenths of a millimeter larger across, resulting in about 2.5mm less insertion into the arm.
Thus, JIS spindles should be considered 5mm longer overall (not on each end) than an ISO spindle of the same actual length.
Comparing spindle tapers is easy and informative! One can compare insertion depth of two different tapers by simply locking the caliper at 12.8mm and measuring how far that each different taper slides between the locked jaws!
I measure spindle end dimensions by putting the caliper jaws flush with a table and then putting the end of the spindle flush with the table, between the jaws, shown below.
This way, the measurement will be at the same 1/8" from the end of the spindle, equal to the thickness of the caliper jaws.
I'm at a loss for words at how sensibly practical dddd 's explanation is here. Pretty much applies regardless what crank you have.

I'm all up for making "12.8 your spindle, and work from there" the new approach for all bottom bracket taper questions. Who's with me on this?

-Kurt
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Old 12-04-19, 02:31 AM
  #38  
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Originally Posted by cudak888 View Post
On that note, wasn't it determined in another thread (I'm hoping CV-6 remembers it; IIRC, he was part of the discussion) that Stronglight's taper is also deeper on the drive side? If I recall, it was not ascertained whether this was just a deeper cut of the same LH taper, or whether the actual start width is narrower or not.

While I share verktyg 's opinion that a fairly used Stronglight crank can be installed on a JIS spindle if the taper matches up from previous installations, I really wouldn't try to put anything but another Stronglight crank on a Stronglight spindle. The spindle is just too different from the rest - even TA - and I usually find it better to pass them on (or hoard them) for when they're absolutely needed.

Since Germany_chris says Italian equipment can be found easily and cheaply where he is, why not go with a Campagnolo Nuovo Gran Sport or Triomphe crankset with matching French BB? Methinks these bits will be much easier to find in his location, suit the period look (if that's a consideration), and open up the opportunity to use compact gearing:




-Kurt
After looking at all the debate that is probably going to be the route I go down.
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Old 12-04-19, 03:01 AM
  #39  
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Originally Posted by cudak888 View Post
On that note, wasn't it determined in another thread (I'm hoping CV-6 remembers it; IIRC, he was part of the discussion) that Stronglight's taper is also deeper on the drive side? If I recall, it was not ascertained whether this was just a deeper cut of the same LH taper, or whether the actual start width is narrower or not.

While I share verktyg 's opinion that a fairly used Stronglight crank can be installed on a JIS spindle if the taper matches up from previous installations, I really wouldn't try to put anything but another Stronglight crank on a Stronglight spindle. The spindle is just too different from the rest - even TA - and I usually find it better to pass them on (or hoard them) for when they're absolutely needed.

Since Germany_chris says Italian equipment can be found easily and cheaply where he is, why not go with a Campagnolo Nuovo Gran Sport or Triomphe crankset with matching French BB? Methinks these bits will be much easier to find in his location, suit the period look (if that's a consideration), and open up the opportunity to use compact gearing:




-Kurt
After looking at all the debate that is probably going to be the route I go down.
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Old 12-04-19, 07:39 AM
  #40  
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Originally Posted by TenGrainBread View Post
The real takeaway is that modern ISO and JIS tapers are the same angle, but ISO tapers are longer. So if you have a crank that was designed for an ISO taper, it might bottom out on the shorter JIS tapered spindle.
I think this isnt true. If anything, a crank for JIS might bottom out on an ISO bb.

For a JIS bb with ISO crank, like I use, I had to account for the difference and get a bottom bracket a few mm shorter.
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Old 12-04-19, 10:39 AM
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Originally Posted by rosefarts View Post
I think this isnt true. If anything, a crank for JIS might bottom out on an ISO bb.

For a JIS bb with ISO crank, like I use, I had to account for the difference and get a bottom bracket a few mm shorter.
You're right, I got these backwards in my wording. Fixing.
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Old 12-04-19, 12:10 PM
  #42  
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My intent is to not change everything tbh even if the FD is kinda crappy Iím ok with that I donít shift that enough for it to be worrisome. Since Iím not sure if the RD hanger is threaded or not Iím not inclined to replace it.

the reality it the bike is pretty and itís nice but itís not a bike Iím willing to drop a grand or so on to ďfixĒ it. A 14 to 28 freewheel, compact crank, and my preferred contact points are as far as weíre going at this point.
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Old 12-04-19, 09:00 PM
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Originally Posted by Germany_chris View Post
My intent is to not change everything tbh even if the FD is kinda crappy Iím ok with that I donít shift that enough for it to be worrisome. Since Iím not sure if the RD hanger is threaded or not Iím not inclined to replace it.

the reality it the bike is pretty and itís nice but itís not a bike Iím willing to drop a grand or so on to ďfixĒ it. A 14 to 28 freewheel, compact crank, and my preferred contact points are as far as weíre going at this point.
Are you 100% sure that you can't get a Stronglight 99 crankset over there? I'll leave it to the ones who know off the top of their head to confirm, but it just might be a bolt-in crank to your existing BB, and have a small enough BCD for a 53/36.

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Old 12-05-19, 01:44 PM
  #44  
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Originally Posted by cudak888 View Post

...I'm all up for making "12.8 your spindle, and work from there" the new approach for all bottom bracket taper questions. Who's with me on this?

-Kurt
I've thought about such a measurement standard for years now, but I wanted to put emphasis more on comparisons of different spindle's tapers than on any actual numbers that might get bounced around as factual data.

My reasoning is that often these digital calipers do not effectively zero out accurately after years of use and abuse, so it's not all that uncommon for one to show 0.00 fully closed, yet give measurement readings on the low side due to some kind of hysteresis (effectively acting like freeplay) in the "electromechanical" mechanism inside one of these things.
For those who have a single new bearing ball of known size, their caliper can be verified as accurate since ball bearings are made to extremely fine inch tolerances. Only with such verification can the numbers be trusted!
However, when simply comparing spindles for differences in their "inserted length" into the crankarm, any caliper mis-calibration is not an issue since both measurements will have the same degree of error.

My oldest digital caliper reads "low" by at least a few hundredths of a millimeter, which is semi-significant in terms of fitting cranks, but could also be a source of online disagreement or statement of erroneous data to the forums. So I encourage those having such calipers similarly put emphasis on the difference between different tapers more than for stating exact dimensions (unless their caliper has been recently calibrated).

One other note here, I've measured Dura-Ace spindles which gave spindle taper width readings slightly larger than other's JIS spindles. However, these are machined tapers on the Dura-Ace spindles, and I detect a slight lengthwise concavity of the flats, which from my experience allows them to have identical insertion depth into the crankarm as other JIS spindles.

Also note that I revised my original post about all this to suggest 13.0mm as a better caliper jaw opening, the better to keep the caliper jaws away from any sort of spindle-end radii or deformity. So let's call it 13mm(?). This is still very close to the end of the spindle, where even small differences in insertion depth will appear more obvious.
So again, it's "13mm measurement point using a calibrated caliper", expressed as the jaw's distance from the end of the spindle.
Note further that this assumes a standardized jaw thickness of exactly 1/8", which is being subtracted from where the caliper jaw is actually contacting the flats. Complicated, yes.

So I think that if we "13.0" two different spindles, that we can actually see the insertion depth difference to a useful degree of accuracy!

Oh, and thanks for what I took as a compliment!

Last edited by dddd; 12-05-19 at 02:01 PM.
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