Kilroy1988 

Hello folks,

My brain isn't working today. Typically, I do my own homework but I'm literally doing homework for grad school all morning... Anyway, the last component I need for a build that I hope to complete this winter is a Stronglight bottom bracket to match up with a Stronglight 93 crankset (double) on a standard English bottom bracket on a Mercian.

If anyone has something suitable or if you can point me to an eBay auction that would match the specs I need. Thanks and much appreciated!

-Gregory

Kontact 

Stronglight branded of Stronglight 93 compatible?

VRJAKE 

Cups like this for early 1970's with a 118mm Stronglight spindle. Most on ebay now are French thread, with some Italian, but English thread BB's do exist. Note the 123mm spindle is for a triple.

https://www.ebay.com/itm/26628015849...Bk9SR6y6lYr9Yg

Kilroy1988 

I suppose I'm open to either but I had a Stronglight branded one in mind. I should have more time to research the issue later this afternoon, but any additional options or explanation would be useful. Thanks!

-Gregory

Kontact 

Any 118mm ISO spindle BB should work. Including finding just the spindle and combining it with someone else's cups.

Otherwise, ISO BBs other than Phil Wood and Campagnolo are hard to find, and I don't think Campy had a 118mm spindle. I've had good luck with Chin Haur cartridge BBs, and they actually have a range of ISO spindle versions.

nlerner

I'm fairly sure that a TA BB with a # 344/118mm spindle will work. I believe I have a complete set I can send your way, @Kilroy1988. Let me know if you're interested.

redshift1

Edco Competition bottom brackets ( N.O.S. ) come up for sale more often than you would think. I'm pretty sure 116 mm axle length would work with old Stronglight cranksets and the chainline is adjustable if you need that. I've seen Edco's in 114mm, 116, 120 and greater axle lengths but just can't recall if I've seen 118 mm.

e.g

https://www.ebay.com.au/itm/36440227...Bk9SR56dlJr9Yg

Kilroy1988 

Thanks for the help, folks. My brain is less foggy now and I realize my error in assuming that the cups might be their own thing too. Neal (Neil?), let me check something out in the morning among my stash and I'll get back to you... Thanks again and cheers!

-Gregory

El Chaba

There are combinations of things that *can* work like mixing brands of bottom brackets with cranks and even spindles with cups. I avoid potential problems by trying to match brands. You can also encounter problems with mixing cranks and bottom brackets from different time periods as some companies changed the spindle interface size from time to time. I would seek out a Stronglight Competition bottom bracket in BSC with a 118 mm spindle. Keep in mind that there was no such thing as “JIS” or “ISO” at the time of manufacture of the crankset in question.

Hobbiano 

I don't know if this is what you need or if it is the correct threading or not, but there's two 118 mm Stronglight Competition bottom brackets in the C&V marketplace right now: The listing starts with "French parts".

Kontact 

I believe there was JIS, and then there was a tacit "ISO" that was a duplication of Campy taper. When ISO was formalized, it matched that taper.

Kilroy1988 

Okay, so it turns out I have a Sugino bottom bracket that I've actually been meaning to remove from the frame in question, and it has a 119mm spindle. The Stronglight crank arms seem to fit over it well, however, on the non-drive side there's ~30mm between the shell and outside of the arm, and on the drive side it's 40mm to the outside of the arm. I assume it'll tighten up another millimeter or two once they're pressed on. Does that seem like a reasonable distance to the outside of the arms and should it be slightly more on the drive side? I'm assuming this Sugino 119mm spindle is really meant to take a JIS triple...

By way of comparison, I have a 1982 Pro-Miyata sitting here and from the outside of the arms to the BB shell on either side is ~32mm with a double and it's more or less even on both sides.

Would a Stronglight 118mm spindle make the distance to the outside of the crank arms more even than this or would there be a slight offset on the drive side in that situation as well?

I hope that question makes sense. Thanks!

-Gregory

panzerwagon 

Please may I be next in line in case @Kilroy1988 passes? I have the exact same setup on an upcoming build— stronglight 93 on a mercian of unknown year (mid 70s).

merziac

Mock it up and try it, if it works, run with it, if not continue to mix and match.

I have never been unable to resolve this with parts on hand or one quick trip to the co-op, ever.

The only really sticky point is if you must have cups that convey the branding you want, still not that tricky IMO.

merziac

Also,

IMO and I know some/many here take issue but persnickity is not your friend, ISO and JIS has helped many times going the right way almost always.

I firmly believe that this far down the line, most cranks have been removed and installed enough to make it a moot point, if it helps you then go with it, if not find a better match.

That being said, diligence and common sense must be front and center, if the spindle only goes in the arm halfway to 2/3rds or less and you still crush all hills with abandon then maybe reconsider this tack, I have never had such a worry.

Kilroy1988 

Hello sir,

The crank arms seem to fit snugly onto the JIS taper but the 119mm Sugino arm seems to allow the Stronglight crank arms to sit unevenly, which is why I suspect that for whichever cranks were truly meant to fit the Sugino it was meant to take a triple rather than a double. I am just wondering whether the offset on the drive and non-drive sides on a Stronglight spindle would be comparable or whether the arms would fit more evenly on both sides.

-Gregory

merziac

Good day? to you as well.

I have little input of this sort, again, my haphazard process of mix and match/run what ya brung has always served me very well but I have purposely resisted the urge to make too much sense of it as it muddies the water and impedes my hack sense on this.

That being said I often do get well off into the minutia of this sort of thing as you probably know but not here.

Many here seem to have had encyclopedic knowledge on this, not sure why none have chimed in yet.

Kilroy1988 

I took apart the Sugino bottom bracket that was on the frame this evening. It's an MT-68, which is an older Sugino model for a mountain triple... It's not in bad shape but not really what I envision keeping on the bike.

However, I'm going to pass on nlerner and his gracious offer because I've decided to just wait until the right Stronglight unit comes around. panzerwagon I wanted to let you know that I'm passing if you'd like to reach out to Neal (Neil?) about that bottom bracket.

I've got bigger problems right now after getting an adjuster barrel screw stuck in the rear dropout and shearing it on both sides during attempted removal...

-Gregory

3alarmer 

...

dddd

A much closer (as in immeasurably different) approximation of the ISO taper would be the Superbe taper AKA the Mighty taper.

The pre-cartridge Campagnolo taper is invariably at least .05mm larger than either the later ISO or the period Mighty/Superbe taper.

The Stronglight Competition taper from the early 70's is, like the ISO and Mighty/Superbe tapers, between .05mm and .1mm smaller than the Record bottom bracket taper of the same period.

For use at least by lighter riders like myself, a 115mm symmetric JIS cartridge bottom bracket can work fine with Stronglight Competition doubles, with the chainline and Q perhaps slightly trimmer than original spec. Most front derailers easily pull inward far enough to give robust downshifting using such a 115mm bottom bracket.
I have similarly used 107mm and 110mm JIS cartridge bottom brackets with Sugino Mighty crankarms, with no issues over long periods of intense (including off-road) riding with my 140lb carcass on board. The chainrings run true and the bolts don't loosen.

I used a 116mm Edco bottom bracket on my Raleigh 753 Technium using Stronglight 93 arms, and the taper matched well without the bolt head bottoming on the spindle. But the crankarms did slightly graze the very straight-shaped chainstays of this frame on both sides under hard pedaling efforts. I suspect that this frame is wide in that area however, so would not rule out use of the Edco Competition 116mm bottom bracket with Stronglight Competition crankarms, especially as the chainline seemed perfect.

The old 118mm Stronglight bottom brackets seem to be increasingly scarce, so it's always nice having alternatives to turn to, at least in the short term.

One more option worth investigating would be the post 1978 Record bottom bracket, it's the longer style so better matching the slightly longer spindle of the Stronglight Competition bb. It's slightly thicker taper should (favorably) add just under 1mm to the mounted chainline of a Stronglight crank.

For purposes of comparing spindle taper sizes, one can lock a caliper at 13mm and test how far that any two spindle's tapers will insert past the jaws of the caliper.
This gives a direct comparison of the spindle's insertion depths into any crankarm, resulting from the relative thinness of the spindle tapers.

A JIS spindle's greater taper thickness will add about 3mm (per side) to it's effective length as mounted in an ISO or Stronglight Competition taper crankarm.
This can make up for a JIS cartridge bottom brackets zero-offset symmetry and shorter overall length.

Kontact 

Except it doesn't seem to work that way, probably because JIS is a shallower taper angle. There are many examples of people using 115 JIS in 115 ISO cranks and getting normal chainline.

dddd

What crank would you referring to that is a "115 ISO crank"? The Stronglight Competition double cranks used both 118 and 120mm spindles, and both had some bit of driveside offset.

Popular opinion on the taper angles is that ISO, Stronglight, old and new Campy and JIS are all 2-degree tapers.
Exceptions to 2-degree taper angle is somewhat rare. Lambert/Viscount could have zero degrees, and some inexpensive early Japanese cranks had I believe a 3- or 4-degree taper (thinking it was SR, does anyone remember?). Lastly, some Italian brand, Ofmega perhaps, supposedly had a non 2-degree taper.

Mentioning here the rarity (of anything not 2-degrees) because I've only ever seen the zero-degree Lambert taper in the wild, none of the others.

Kontact 

A "115 ISO cranks" is a crank that the manufacturer says is ISO and specs a 115mm ISO spindle for. And 115 is just a random number. In my case, I have been using a Mavic 631 which is designed to use a Mavic BB with an ISO taper of 114mm length, yet I've been riding it with Shimano 114mm BB and normal chainline.

The lesson here is that endlessly repeating "they are all 2 degree tapers" will quickly fool you into thinking that you can predict what length JIS spindle will substitute for an ISO/Campy one, but that's because - like idiots - we have all been repeating something from Sutherland's that isn't true: JIS and Campy/ISO are not the same taper angle.

Anyone can observe this by simply holding the taper of several spindles against each other. Yet, I am seemingly the only mechanic on earth that has done exactly that.


So repeat the 2 degree thing all you want - it is baloney. And creates a false impression of what kind of predicted press depth different spindles are supposed to produce. But JIS is obviously a finer taper angle.

dddd

Not everybody here "blindly trusts Sutherland's", many have found good reasons not to always accept their simple or generalized explanations.
To their (Sutherland's) credit, having to document stuff like this in the realm of bicycle "standards" was never going to be easy, and I don't think that they have spent much time in recent years updating or correcting square-taper spindle data, especially their very old data.

Two degrees is something I have found to be reliably relied upon when trying to arrive at a best first-try spindle length using ostensibly non-matching components.

Measuring the offset of an existing spindle that is to be replaced with another brand needs to be done correctly, it's not that simple and requires a small bit of math, though becomes simpler after the bb assembly has been installed in the frame.

Complicating the "offset" issue is the way that some define "offset". Offset is often referred to as how much longer that the driveside spindle end protrudes versus the non-driveside end. But note that offsetting the bottom bracket in the bb shell by 1.5mm results in the driveside end then protruding a full 3mm further than the non-driveside end, thus making me suspicious of any published "offset" figures.

With the offset dimension correctly measured and applied using a consistent method, and with the spindle taper type (size, i.e. thickness) correctly identified, I've had no problem getting good chainline on the first go, even when I am using a JIS taper in place of something else.

JIS, Campy (including their newer cartridge style ISO-sized spindle tapers) and Stronglight are all always actually 2-degrees, something that can be relied on 100% of the time.

Kontact 

Okay, so you are yet another "expert" that refuses to actually hold two spindle ends together to observe their difference in taper angle.