So i'm converting an old UO-8 to fixed gear and thought someone in this end could help. I'm getting the Velo-orange french threaded BB. my problem is I intend to put a crank on this bike that is ISO when the BB is JIS. I'm aware that the crank will be off(outward) by 4.5mm if put them together, but I need to get the chainline as straight as possible and only have this crank. would getting a 103mm BB(the smallest VO offers) be ok considering the extra hang off of the crank? Or, may filing out the square in the crank be an option. I'm in this one too deep to turn back now!

It's all going to depend on the specific crank itself and which position you'll be using for the chainring. You should post more information.

I'm assuming that the u08 has a 126mm drop spacing? I'm trying to do something similar with a fuji s-10. Measuring the the rear chainline using sheldon's method gives me something like ~47.5mm (this is with a 120mm fix/free hub and a 1/8" cog with spacers)... My understanding is a 103 bb will yield a 42mm chainline if using the inner mount on a road double crank. So if your crank will be pushed out about 4.5mm, wouldn't this give you a pretty okay chainline? My problem with the fuji is that the bb shell is 73mm and all the cartridge bb's I'm finding are for 68mm shells.

Why not just get an ISO crank? Old-generation Campy Chorus are pretty darn cheap. With a crank with too much Q-factor, I tend to feel like I'm duck-paddling rather than pedaling.

Too many variables in play....

He's got an ISO crank. The question would be why he doesn't just find an acceptable JIS crankset instead, for the JIS taper on the VO BB. That's the way I'd go. And an old JIS crank is likely even cheaper than the aforementioned chorus... OP, what's special about the crank you intend to use?

OP, chainline can be manipulated several ways. For example, if the BB is asymmetrical (IE, the spindle extends out further on the drive than the non-drive side) you can flip the BB around to move the line in. You can do this with a French thread BB such as the VO because the threads are the same on both sides. Or you can re-dish the rear wheel, which also involves moving spacers on the rear hub so the hub is no longer centered in the drops. Or you can move the remaining ring over on your cranks; this can only be done if you've converted a double to a single (Via use of shorter chainring bolts).

When you get into these projects, esp. with older Frenchies, you sometimes have to deal a bit imaginatively with problems as they crop up.

edit: and whatever you do, don't file the crank insert. Sounds like a bad idea on several levels. Really, without seeing the set up in question, it's hard for even a skilled mechanic to make an sort of determination. One of the more irritating parts of the fixie revolution is folks asking over the internet for the spindle length to get a perfect chainline. I recall one fellow who wanted the perfect chainline on an old PX10. He came back and reported he'd found the perfect spindle for the SL crank as a fixie, and now had a perfect chainline, but the non-drive side arm was now hitting the stay (he'd ignored advice telling him he need a longer spindle, and insisted a 103 or some such would give his bike street track cred, or somesuch). You really need to be on the scene, observing, to offer much usefull advice-- as Miami Jim said, too many variables. So you may have to use more than one of the above solutions, or even one that ain't mentioned-- but not the filing, no no no.

the reason I don't get a new crankset is because I just bought the crankset I have now for more than I would the BB. in that case I'm pretty firm on keeping the crank and just mixing parts that will turn out ok. has anyone ever filed a spindle down or filed out a square hole wider. Or considered it.

The UO-8 will have 120mm spacing in the rear.

I would NOT file down the taper of the spindle. First, it's hard to do accurately. Second, I believe that steel is pretty hard, so you'd need a heck of a tool to do the job.

+1 It has 5 speed spacing, 120mm as I recall.

Unfortunate, but the bb is the key to rehabbing a UO8, not the crank. Need to replace the crankset, as bb alternatives are limited on the UO8, unless you get really lucky.

100% correct, and I'm sticking to that story.

Phil Wood can solve your problem, but it will cost you about $150.

It's too bad you can't get EDCO French bottom brackets any more. The one on my Peugeot allows a few miilmeters of adjustment so you can dial in your chainline like a Phil, but at half the cost.

I will repeat: DO NOT FILE DOWN THE CRANK OR SPINDLE It is a very bad idea. Buy a different crank. Or use the one you have as is and deal with the extra stick-out, and adjust chainline with another method.

what about rethreading to italian and finding an italian ISO BB? I've heard it is possible to rethread a french to italian. would this be easier to find?

No comment on rethreading but yes, Italian BB's are very easy to find.

Why no comment on rethreading? OK, I'll make comments...

It's true that Italian threading has a larger inside diameter than all the other threadings. We would use Italian threads when we had a trashed bottom bracket. It's a decent revival technique.

But it requires expensive tools, and not many shops have them. Once you find someone able to do it, I don't know what he'll charge you. Ask around.

I didn't know Italian thread BB's are easy to find. Why is that? Is Italian threading still in common use?

Yes, Italian threading is still current.

Start with a 107. if that's too small, get a 110. if it's super wide, use a 103. 107 and 110 french BB's are our best selling sizes by far. it's probably half our sales overall.

What spindle was in there originally? or was it a cottered crank?

No comment because I've never done it!!!

As wrk101 has mentioned, Italian BB's are still current. A quick Ebay search yields 56 hits for Italian, 2 for Swiss (swiss made not neccessarily swiss thread) and 5 French (only 2 complete).

Since this thread is back, I also have an on-topic question.

A customer is asking me about upgrading his U08 with cottered cranks, and would like to use road double cotterless cranks. I have a few JIS cranksets from which to choose. I was considering the Velo Orange French Bottom Bracket; what spindle length would be best for a road bike double (Shimano 600 or possibly a Sugino set)?

Thanks

It depends on the crank profile but its going to be in the mid to upper teens. What ever the particular crank would normaly take in British BB should be what'll with the VO BB +/- for the symmetricalness of the VO piece.

Thanks Jim!

I wouldn't do this myself, but I asked about it at a good LBS, and the price for rethreading Italian it makes a Phil Wood solution look cost-effective.

There are several alternate ways to deal with chainline, based on what OP is willing to do.

Mount the chainring to the inside of the crank arms (in the small ring position). Doesn't look Tarck, but works.

Use one of the (BMX? MTB?) rear hubs with 47.5 nominal chainline rather than 42.

Build rear wheel using a road hub with with equal or even reverse dish (no flipflop) and spread the rear stays enough to allow chainline to slide over. Spoke angle will be lower than with a tarck hub, but no worse than a road bike, for sure. This requires measurement, calculation, and good communication with bikeshop if they're building the wheel; but as long as you've set the hub spacers and cone/locknut setup for them, and the spacing of rear stays is centered, it should be easy enough.

Go singlespeed rather than fixed. Use a freehub rear hub (instead of a tarck hub) - not as kewl visually, but allows very flexible chainline with a single cog and a spacer kit.

From my experience trying to get a 42-ish chainline on a JIS road crank (Shimano 600EX 6208) using a symmetrical JIS cartridge bearing BB, 68 mm wide bracket, keeping the chainring on the outside, I'd recommend starting with the 103 mm. If it's too narrow (crank hits drive-side seat stay, for instance) then move it over using a freewheel/BB shim behind the drive-side "cup". The 103 may not work with an ISO crank anyway, but I doubt you'll find anything narrower than that.

There's no cut-and-dried solution here that doesn't require fiddling and expense, trial and error. If OP didn't want such grief, should have started with a Bianchi Pista, rather than a UO8!

Still looking around and I recently came across some old french BB's. I also just discovered(which I'm suprised no one mentioned) that T.A., old Stronglight, and Nervar spindles all used ISO spindles. Right now I'm looking for them instead, but only under the circumstances that the BB is NOT loose ball. For I have a strong disliking to loose ball bearings and the possible problem of losing them

"There's no cut-and-dried solution here that doesn't require fiddling and expense, trial and error. If OP didn't want such grief, should have started with a Bianchi Pista, rather than a UO8!"

Funny thing to that is my first fixed gear conversion was (and is still riding) an 86' Bianchi campione del mondo(The italian made one). got it for free on junk day in near mint condition. I've ridin it very hard for about 6 years now 2 free 4 fixed!

Its a uo8 so I'd buy a shimano un52 bb and just force it into the shell
A bottom bracket tool attached with a crank bolt to the bb and a big wrench approach
Will get that bb in there really tight. Sure it may deform the threads a little but it's a uo8.