cranks too close to frame
 

I think I've been here before, but I can't remember the solution or explanation.

Quick story is the Chorus cranks I would like to use with an 8S Chorus setup sits too close to the chain stay.

back story. I am setting up a nice maybe late 80s Bianchi. well actually no, it's not so nice. it has great bones but is in pretty grim condition, cosmetically at least. But before I commit to an expensive restoration and paint job i thought I would set this back up and ride it, to see how it feels, to see if it's my size (the frame construction is pretty weird, with these headtube and seattube extensions it's hard to figure out what size it actually is) and to see if there is Love between us.

It came to me as a 10S Campagnolo Record set up. but since it appears to have been left out in the elements for a couple of years, the brifters were seized. So I stripped it and started over.

I left the bottom bracket installed though (because I suspect it might be French thread and I don't want to mess with that, or try to replace it.) It seems smooth.

But 2 of the three sets of similar era Campy cranks touch the chainstay on the Drive side. A Mirage set seems to fit and I will just use that for the testing period.

but what's the deal? BB axle length?
why would some cranksets sit too far in and 1X fit OK? when all seem about the same vintage.

I would very much doubt a Bianchi would have French threads. Italian maybe, but probably not French.

Carefully look at the bottom bracket without the cranks to see if it lists the threading. You may have to remove it to verify.

Many of the early bottom brackets were off-center. Make sure it isn't installed backwards. I'm not quite sure of the reason for that, but I think some cranksets were made specifically for off-center bottom brackets. So installing them on a symmetrical bottom bracket would be problematic.

From your photo, it looks like the inner ring is closer to the chainstay than the outer ring. As long as nothing touches, it may be ok. Or, perhaps cranksets with smaller rings?

Where are the ends of the cranks, near the pedals with respect to the chainstays?

The inner chainring on my 2000 Bianch M Alloy Pro is excrutiatingly close to the chainstay... but it doesn't touch and all works correctly.

I wonder if repeated removal & reinstallation of cranks on a square taper BB might make it so that they press in too far.

If you consider the BB to be a "consumable", if you intend on keeping the bike I'd say try replacing that. It's most certainly *not* French, but either Italian (36mmx24tpi) or English (1.37"x24tpi), and the thread should be printed (or stamped) on the BB somewhere. Measure the shell, get a new BB, and so on.

I know of no Bianchi with a French threaded BB. Yes repeated tightening (of too much) of the crank retaining bolts will pull up the arms on the tapers a bit more then intended. But until the spindle come up flush with the retaining bolt's seating face there's nothing bad about this extra pull up (assuming the rings and arms clear the stays). Campy did use different arm spindle hole locations, WRT the arms and rings, over the years. Much like Shimano's LP and SLP did. Could be that you have mixed generations.


BTW looks like that Chorus large ring is well worn... Andy

You could always remove the bottom bracket and then install a shim behind the right hand fixed cup.

Also, please check how much of that seatpost is actually BELOW the top tube of the frame. If there's only a bit of the seatpost below thet top tube there's a good chance that you can snap off the seat tube where it extends above the top tube. I've see that happen when there was less than 2 INCHES of seatpost BELOW the top tube.

Cheers

For a certain, fixed, constant length of a BB axle: not all the cranks have the chainrings at the same distance.

My guess is you either need a longer BB axle, or the longer part of the axle was mounted on the left side, in which case you could just put the axle the other way round.

I too was surprised to think this frame might have French threading. But the first suspicion came from my local frame shop, Malcolm of Biseagal here in Toronto.
I'd taken the frame to Malcolm because I could not get the top cup of several headsets I tried to thread onto the fork steerer. Turns out it was 25mm OD which apparently is French and non standard. Malcolm had to rethread the steerer and he carved off an astounding amount of metal.

Plus the threaded part of the steerer does have a flat on the back and not a slot, and apparently that is typically French too.

Also, the bike did come from France.

Finally, I just measures the BB shell at it is definitely 68mm which could be French or English. 70 would be Italian and so I am suspecting French, given the fork steerer threading.

Odd duck this one.

My later campy square taper cranks had an offset bottom bracket, I think that Campy used offset bottom brackets on the higher end of their line (chorus, record and Super record) and used symmetrical bottom brackets on the lower end. Maybe that is why the Mirage fits. The different cartridge bottom brackets had different retaining rings and needed different tools to install them.

Your bottom bracket spindle may not be the correct length or taper for your crankset. Have you measured the spindle? Both for overall length and symmetry? You can look up what length is required for your crankset and compare.

Taper (ISO vs. JIS) is probably correct ...if the previous owner didn't install a mismatched spindle/crankset combo. Campagnolo cranksets are ISO. Most others, particularly from Asian manufacturers, are JIS.

And instead of judging your crankset/spindle compatibility by chain stay clearance, you may want to consider measuring chainline instead. Stay clearance varies from bike to bike. Chainline is pretty much standardized, and directly affects whether your derailleur can reach your inner and outer chainrings. Chainline for a road double should be about 43.5 mm, measured from the frame's centerline to the midpoint between your chainrings.

A Bianchi's not going to have a French bottom bracket, even if it was sold in France. It'll be either Italian or English, largely depending on where the frame was built. If it's an Italian frame, there's a pretty good chance the bottom bracket will have Italian threading. If the frame was contract-built in Asia, the bottom bracket will almost certainly be English threaded.

If the existing bottom bracket isn't a cartridge, you may find threading markings on the cups, which will identify what you've got:

1.370" or 1.375" diameter, 24 threads per inch, 68 mm shell width = English
35 mm diameter, 1 mm thread pitch, 68 mm shell width = French (or Swiss)
36 mm diameter, 24 threads per inch, 70 mm shell width = Italian

Not every crankset is designed to use the same spindle length. Even cranksets from the same manufacturer and era may require different spindles. It varies from model to model. That's why there are dozens, maybe even hundreds, of different spindle configurations. (Yellow Jersey lists a bunch of 'em.)

Here's a shot of the drive side of the BB.
Unlike any I've ever dealt with. I don't even think I have the tool to remove it.
What does the RIGHT mean in this case? "install this on the Right Side"? or "this side is RH threaded"?

Unfortunately any other markings are obscured.

This is all rather odd. Perhaps Bianchigirll would have an opinion.

I think I see where BIANCHI is engraved on the bottom bracket, so I'm assuming the main frame is genuine Bianchi.
However, the Celeste on the fork crown appears to be a different color than the rest of the bike, although it could be a photo artifact.

It is possible the fork was replaced at some point in the past, and the bike was given a French fork and headset.

The best way to know for sure the Bottom Bracket threading is to find it listed on the BB. If it is a ball type BB, it would be listed on the cups. If it is a cartridge type BB, it may be listed on cartridge, and will need to be removed to verify.

Anyway, I would have already removed the bottom bracket to inspect.

You haven't really discussed the crank arms with respect to the chain stays. That will tell a lot about symmetry.

Anyway, you have a few possible solutions:

• Just use the crankset that fits.
• Acquire a new bottom bracket or bottom bracket spindle to match the cranks you desire.
• Ignore the small ring being close to the stays if it isn't rubbing.
• Look for a smaller small ring (different cranks?)
• Perhaps find a small ring with a tooth offset closer to the outside
• Shim the bottom bracket as suggested above.

I'm guessing Right means Right side.

Clean the mud off and see what it says under the mud.

I'm seeing Campy Compatible Bottom Bracket/Cassette tools for about $10. Probably would be good to add to the toolbox.

While we're waiting on bottom bracket confirmation or measurement...

This doesn't make sense. You can't cut a French steerer tube down to another size because French steerers are smaller, not larger. French steerer tubes are 25.0 mm while Italian, English/ISO, and JIS are all 25.4 mm.

Even if French steerers weren't smaller, it would be a bad idea to convert to or from French threading because the thread pitch is slightly different. Italian, English/ISO, and JIS are all 24 tpi. French is 25.4 tpi (1 mm thread pitch). Because of the slight mismatch in thread pitch, you'd effectively strip the threads if you tried to change the pitch.

Hmmm

Italian crown race seats are frequently cut down to English/ISO

Cleaned up the face of the DS and indeed it is marked 1.370 x 24 TPI, so English.
Still, I wonder about that steerer threading.

you are correct. I got that all wrong. in any event, the cups would not fit the steerer. I don't know why.

those are VERY good suggestions. I hadn't thought about the seatpost issue.

Yes, but the crown race diameter is separate from the diameter & threading of the steerer tube itself.

For example, a JIS fork has a crown race seat of 27.0 mm. An ISO fork has a crown race seat of 26.4 mm. Both have 25.4 mm steerer tubes with 24 tpi threading.

[IMG]campy bottom bracket[/IMG]

[IMG]from my Masi[/IMG]

hopefully you will get these photos but they are my campy cartridge bottom bracket. it is similar to yours, even says right on it.

obviously I don't know how to post photos, so here are links to the photoshttps://www.flickr.com/photos/buster...posted-public/

https://www.flickr.com/photos/buster...posted-public/

Again. After looking at the images of your bottom bracket I'd try using a shim under the fixed cup of the unit. The shims should be available from a decent bike shop.

Cheers

Got it. and the tool to remove that BB is just a Campagnolo cassette tool? that I have.

Thanks for all your help and suggestions.
I got her built finally. Using the Mirage cranks with 8S Chorus setup for the rest.
Rides really really well.
and funny, once you get her dressed up with all the bits on her, I don't even notice the rust spots on the frame. Hardly seems worth refinishing (this provisional build was intended to test the size and ride quality before committing to a repaint.)
I think that looking at a bare frame just accentuates any flaws.

extra bonus - I got to deploy all my Celeste coloured parts.