Germany_chris

I'll pick up my new to me French bike tomorrow after two failed deliveries. Since I've never owned a French bike I'd like to know whether French cranksets like the Stronglight on mine are JIS taper. I know the threads are French, I know VO sells a French thread JIS BB but what I don't know is whether the stock crank is JIS.

ToniH. 

Beatiful Mercier.

3alarmer 

...no, they are not JIS in standard taper, but you can make the crank work on a JIS BB unit in almost every case. The JIS tapered end is a little longer. So if you measure what's on there now, and then order the same length spindle in a JIS, it might push the cranks out a little bit from where they now sit in reference to the stays. Usually, this is not a problem for people. But it's possible with some reading, measuring, and deep contemplative thought, to order one slightly shorter and get the crank to sit pretty close to where it was originally. It's kind of a crap shoot on this, because if you order the next size down and the chainring interferes with the stay, the things are not returnable once installed.

Read the stuff here.

Germany_chris

Got it..campy it is...Thanks!!

TenGrainBread 

What do you mean by "campy it is"?

Germany_chris

Quote:

ISO square taper spindles run longer, and taper down to a smaller end than J.I.S. spindles do. Most European-made square-taper cranks and bottom brackets use the ISO dimensions.

https://sheldonbrown.com/bbtaper.html

I have old an old Stronglight crankset which means ISO, so I'll just get a square taper Campy crankset..

Since I'm all Italian all the time with bikes it's not going to break my heart to go that route

Salamandrine 

They aren't JIS technically, but in practice it's close enough. JIS and ISO standards weren't used when that bike was new. They are in between JIS and ISO but much closer to JIS.

I've measured JIS versus vintage Stronglight last time I had both out, and they were close enough to be within production tolerance of being the same. JIS is a very tiny amount larger. Sorry I don't have the numbers in front of me. Cranks might sit out ~1mm more.

Thing is, Stronglight cranks are pretty soft alloy. It's nice because they don't crack, but if they've been maintained the crank tapers have likely spread open a little. Tiny bit fatter spindle of JIS nicely compensates for this.

non-fixie 

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.

seypat

What crank will you be putting on? If you are needing lower gears/a compact setup, put a Stronglight 99 on and run it as a compact double.

Salamandrine 

Yes, but Sheldon is incorrect about this. It was once the prevailing wisdom but it's wrong. I used to think they were ISO or close to it too, but they are not, and I was incorrect. I've since measured for myself.

There's another discussion about this in the archives from a couple years ago. I'll try to find it.

TenGrainBread 

First of all, Sheldon's evaluation of things is controversial here. Jan Heine claims that older French cranks from TA and Stronglight use a taper similar to JIS - that the standard we know as JIS today was developed by Japanese manufacturers copying the taper on such cranks. So it is far from clear that Sheldon is right about your Stronglight crank being ISO. https://www.renehersecycles.com/bott...s-demystified/. Some others claim that most older tapers don't match the modern ISO and JIS standards, but are close enough. There have been quite a variety of actual tapers measured.

The real takeaway is that modern ISO and JIS tapers are the same angle, but ISO tapers are smaller. So if you have a crank that was designed for an JIS taper, it might bottom out on the smaller ISO tapered spindle. Furthermore, if you have an old crank or spindle, it might not match what we currently call ISO or JIS. As I said, there have been a lot of tapers measured to various lengths. Most if not all are pretty much the same angle. It might take some experimentation to get the right spindle when replacing your bottom bracket, but in practice it's pretty easy.

My real question is, why do you want to replace the crank/BB at all? It looks like the bicycle already has a bottom bracket and crank installed. That Stronglight crank fits the Mercier frame much better than a Campy would.

verktyg 

I threw this Flickr album together one evening about 10 year ago while I was installing a BB in an old Gitane frame that i was building up to use as a SS wet weather beater.

https://www.flickr.com/photos/282672...57627678462359

Read my comments below the photos - I need to update this info.

I recently mounted a Stronglight 93 on my 1971 Raleigh Competition using a Campagnolo Veloce/Centaur BB cartridge. I used the longer 116mm spindle. These are still available dirt cheap.


The BB was 66mm wide rather than 68mm so I had to use two 1mm spacers behind the drive side cup.



Chain ring to chain stay clearance.





Worked perfectly!

Once a crank arm has been mounted, the soft malleable aluminum has deformed enough that all of the specs are out the window.

If it fits, it works!

verktyg

Germany_chris

This crank is what raised the question..it's Stronglight and compact...but JIS

seypat

Thanks, now the board can give you more info. Just my opinion, the replacement Stronglight is not as pretty as that drilled 93. But, if you need lower gears, I guess you have to replace it.

Germany_chris

Gent's...the idea is not to replace the bottom bracket..The gent I bought this from is a bike builder by trade and he said the BB is in good shape so ideally I don't want to remove it. I would like to find a crank that will "just work" it's not a money issue, it's not a preference/ego issue so if I can just bolt a #random campy compact on the bike that's great. Ideally I'd like to pull all the sexy drillium off the bike and replace it with more pedestrian (read Centaur/Veloce) components that can take the commuter abuse without tears.

seypat

For the discussion, Shimano JIS on the left. Stronglight 93 ISO on the right. The are not very close.

seypat

If that is the case, then all you need is a Campy crankset that will go on a 118mm ISO BB spindle. That is what is in the bike now. Check the Centaur/ Veloce specs to see if that is the BB length they need. Velobase is your friend. If Campy does/did not make a crank that used a 118mm spindle, then you will need to get a 68mm spindle with the correct length for the crank you choose. The 68mm is the width of the BB shell on the Mercier.
https://velobase.com/ListComponents.a...6-f75628ea75e7

On a side note, putting Italian components on a French bike is like putting those french components on an Italian bike. Uggh. And for your last sentence, think about what type of road/weather conditions existed in France when that bike was made. The roads were a whole lot worse than the ones you will be riding on. The people back then/over there actually used their bikes for daily transportation. A lot of them were the only form of transportation they owned.

Germany_chris

I'm "over there" so I can by oldish Campy for cheap. The thing is all those old French components are pretty and at this point not replaceable so if I pull them and throw them in a box I have beautiful, polished, unique parts but if I ride them in the sleet, rain, and salted snow I'll have crunchy junk (or at least not pretty) in a couple years. The flip side is if I spend a couple hundred I can have entry/mid level Campy that no one will miss when they get all crunched up.

I'll admit the bike as it sits gives me a pants tent (c'mon drillium and hammered fenders) I also don't want to ruin it. Yes I could throw a Shimano/Microshift mix on it but that's not me and outside my comfort zone.

I'm at a crossroads the purchase like most I make was all emotion, I bought a sexy bike IMHO but the reality is I bought bones. This isn't my first go round with emotional purchases and I love me some resto-mods so that's the direction it'll probably go no matter how rational I try to be. In the end if I can inniecycle the headset and Campy the running gear I'll have a French bike I understand and have the tools to fix even if it's not authentic.

Salamandrine 

I don't think simply riding this bike is going to destroy it. I commuted for over a decade on my old PX10, often in the rain, and the parts never got to be crunchy junk. Us old farts rode in the rain all the time and our old fashioned bikes never did melt.

If it were me, I'd ride this bike more or less as is, with a couple minor upgrades. I'd suggest something like this: First strip down this bike to the frame, and spray the tube interiors with your favorite anti rust spray. Replace all the open bearings with modern sealed units. Start by swapping the BB with a modern sealed BB. When the cranks are pulled, you'll be able to verify with a micrometer the actual spindle end size. Next replace the HS with a sealed unit. Swap in whatever wheels you like, again with sealed hubs. This will make things much better for sleet and rain and snow. Everything else, give it a good cleaning and lubrication, followed by a couple coats of wax. It will be OK. Try to keep it clean and rewax every year, and it will be just fine.

seypat

Oh, you want durable and cheap. You should have said so. Put Japanese stuff on there and be done with it. Even lower level Suntour or Shimano will shift better and last as long. Probably look better also.

Germany_chris

In Europe Japanese isn't cheap Italian is..

3alarmer 

,,,FWIW, when you call the experts at Phil Wood to ask what to order for certain Campy cranks during a certain time range (might be the late 70's ...I don't remember for sure), they tell you to order the JIS taper version. I'm also a trial and error guy on this, and I don't think there are any definitive answers. As already stated, people have been trying to come up with definitive answers for crank and spindle swapping the entire time I've been fitting and installing different cranks on bicycles. And I'm still doing it by trial and error. It's just that my trial and error is informed by a little knowledge....which is always dangerous.

But if you know that new compact Stonglight is what you're gonna use, for something that new they must have a stated option for the preferred spindle. If you try the thing on the spindle already on the bike, and you can't get it to work, your fallback plan B is to buy that recommended spindle in a French threaded version.

repechage

A few words on the VO French Bottom bracket... the spindle is plated and very smooth. I think too smooth. I test installed a Stronglight and TA crank sets and then removed the bottom bracket.
I am not sure what I will do. Concerned I attached the cranks dry, I could not achieve 45 nm in torque... it got 2/3 of the way there then... just felt as if I could keep on going.

ThermionicScott 

Aren't the current Stronglight cranks forged by Sugino?

Germany_chris

I dunno..