It's just an alternative idea for a setup. Sometimes you do things like what dddd proposed because you have stuff in the parts bin or just want to see if something will work that nobody said will work.

Jyl, as the OP, the pictures are very interesting, and thanks for doing a test! I have a few questions, if you have time:

What is that interesting frame???

What is your chainline measurement?

Is the Q of the crankset equally distributed left and right?

I appreciate your comment about the FD travel limits, but I think we can't really judge that if you're not using a triple FD - I'd expect they have different travel limits than the double FDs.

So, a little more information may help:

The bike in question is my Terraferma 650b. It has a 28.6 mm seat tube and down tube. The rear is spaced 130 mm and I am using 10 speed gear gearing. I am looking to change it all over to Campagnolo 10-speed indexed with the Record triple. The crank is "modern," late '90s or at least pre-2010, in aluminum-colored aluminum. Chainrings have a dull finish - nickel plated? They are marked "10 speed". I've done a few crank fittings to this Terraferma and have always found that it's a challenge to get good clearance between the crank arm ends and their respective chain stays. I want the chainline to be correct with about a millimeter. I think I can measure it that well with consistency.

What it has now is a friction-shifted TA Cyclotourist double, 28/44 with a shimano 11/28 10s in the back. It shifts very well in the back with an Ultegra 10s chain. But I want to add a triple to get more gears that are usable. I'll probably go with a Campy 12/29, 12/30, or 13/29 in the rear after convert my hub to take Campy (it's a White Industries, they sell a conversion kit.) I have a problem with upshifting and over shifting. I can do it right with intense concentration, which means that setup is not MY best choice for centuries or longer rides. Hence I want to go to front indexing. Being a Campy Enthusiast, I'm taking this opportunity to Go to Campy on this bike.

My experience with Campy Record Triples (same one as this) installing one (with the Asymmetrical BB) on my Mondonico is that the installed clearance between the crank base inner edge and the BB shell can be small, such that I don't think a few mm offset is a good idea. On that great old Italian road bike, the crank arm clearances were not a problem. But those clearances will be much tighter on my Terraferma because it is designed for 650x42b.

That is my description of my situation.

Frame is Vitus 997 OCT. Appx 1997-ish French bike.

Q is slightly more on drive side, by 2-3 mm I estimate.



Can't say about the chain line as I haven't a cassette yet, hence have not installed a chain. Eyeballing from above, it looks like it will be okay. Not perfect.



I assume there was a Record triple FD in the early 2000s period, but I'm not wanting to have to find one, so I hope the double works.

I did not bother earlier as the information above I felt was needed to make any comment that would be useful.
It is the chain stay root width and divergence, overall width along the way that is really going to be your issue. Chainline may suffer to get the clearance for the inner ring and or the backside of the pedal bore.
There is a reason many modern bikes in plan view have concave chain stays.
If you have any Campagnolo period BB at your disposal, I would do a test fit. You may well need a longer overall spindle than you would like to clear the frame. Keep tabs on the chain line and note it, measure off the shell or seat tube to get your target overall lengths per side, and let the assembly advise you for certain.

What Campy recommended for this crank is dependent on the fact that this crank was designed specifically for a 130mm dropout spacing.

What frame is this? What is the dropout spacing?

Whether a particular bb length is ideal for a particular crank/bike setup actually depends on a lot of things.

The bb specifically designed for this crankset is conservatively long, for use with a great majority of bike's chainstay configuration and seat tube diameter, but is not necessarily the best choice for you and your bike.
I would first try for something that is effectively a little shorter, but in my case I have parts here to test out in a matter of minutes, so I can guess and then confirm at no cost.
I do this all the time, but I don't "worry" about it or stay up nights "thinking" about it.
Sometimes the outcome is marginal, and I can either true the crank so that there is a good couple of mm clearance all the way around the crank's rotation, Or I can pull the bb and install a spacer. Either way, it gets done, and the final test is whether the front derailer than has enough "authority" to pull the chain down to the granny ring while under pedaling forces.

I test-ride a lot of road bikes with triple chainsets, and am often dismayed by what seems like excessive chainline on many of them.
Unfortunately, today's cranksets with integrated bb spindles don't allow for any tinkering with the chainline measurement.
Some setups have such severe chainline that running the big-to-big has the chain trying to derail itself with nothing but the front derailer pushing it back up.
Not gonna have that on my bikes, but it should be said that I'm not a tourist and so won't need to make much use of the smaller rings with many of the smaller cogs.

Like I said, I think this Record symmetric bb is great because it potentially allows the owner to choose how they want the chainline to play with any chosen frame spacing, cog stack width and riding style.

I'm sorry there has been some confusion about my bike and my question. I guess I was not sufficiently clear. My question is not, "what BB do I need, or what is the procedure for optimizing a BB?" It was as I stated in post #1 : Does anyone here know the difference in quantitative terms between the symmetric Track or Pista BB and the Asymmetric one, and can share measurements?

My frame is (again) a Terraferma, a US made custom. It is designed for a 130mm spacing. It has a 68 mm BB shell, English threaded. Except for possible over width across the outer edges of the chain stays, its details are quite similar to those of my Mondonico, a classic Italian design. The Campy Record triple I installed in my Mondonico uses this same Campy Record 111 mm Asymmetric. It has correct chainline per Campy spec, and balanced Q left to right. It is a joy to ride in part because of its symmetry.

Again, I'm not asking for instructions on hand-fitting and optimizing for this frame - sorry, not what I asked! And I have done so several times for this frame, already.

You say the BB designed for this crankset is "conservatively long" - what do you mean and why do you say that? Have you ever installed one with the crank recommended for it? Or do you perhaps have the dimensions for it, including left to right offset? If so, then that is the information I am looking for. My experience is that it is an excellent fit for a road machine with standard dimensions.

I'm glad you don't worry and you get things done. I hope you don't think I've accused you of incompetence.

The Centaur is symmetrical, as opposed to the Record asymmetrical. Technically, you should use the asymmetrical for a Record/Chorus triple, the symmetrical for Centaur or Comp Triples. There is a 1mm difference.

HTH.

Checking my installed BB's today, the Chorus seems to be at 58mm DS offset, where the Centaur is 55mm, as expected. I pulled the cranks, did not pull the BB, but it looks like 3mm, not 1mm as I previously was led to believe.

The Chorus was English, the Centaur Italian, not sure if that would affect the offset measurement or not.

jiangshi, thank you very much! 2 beers for you, if we ever meet! I think the Italian and English should show the same offset - the only difference is that the part that's inside the BB shell is 2 mm longer for the Italian than for the English. And that 2 mm should be evenly distributed.

I would measure the difference in stub lengths from the BB shell edge to the end of the square taper, of course with the crank arms removed. This is actually how SER (shell to end, right) is defined in Sutherland's 4, 5, and 6th editions. Then I calculate SEL by subtracting SER and BB shell width from the spindle length.

Unless your real purist for $110 you may as well buy a modern cartridge.

I measured from center of the BB shell. Not going to pull the crankarms again, sorry.

Your help is much appreciated. Just trying to share how I measure it. I did not intend for you to pull the arms again, or really even once.