All the big names had the equivalent of Bianchi Formula Columbus tubing - butted frames of unknown specification.

While you can't tell SL from Champion 2 with a caliper, you can tell the center and butt thickness difference between SL and Cromor. The water bottle holes give us access the the center wall of the down tube once you account for paint. And you may get some okay butt dimensions from the inside of the BB or head tube.

Has anyone tried this?.

I understand what you're getting at, but wouldn't access to measuring the thickness at the "water bottle holes" be blocked by the brazed-on bosses in the holes? Unbraze them, drill them out, how would you measure it? (Just my 6:30 a.m. brain trying to think about it.)

Aren't there machines that do this?

https://en.m.wikipedia.org/wiki/Ultr...ss_measurement

No need to poke around.

The other thing though, i highly doubt these specs are not really known. Maybe not by us, but i bet tube manufacturers cut open each others tubes all the time and look what's inside.

My Bianchi with Formula One Columbus tubing sure rides like SL (to me), butt.... who knows each tube?
No destructive testing planned for this sweet thing.


I was not particularly impressed with Tange Champion #2 tubeset on a Centurion I owned many years.

Guess you could measure tube thickness ultrasonically. Not sure how accurate that would be though.

The only mechanical method of measurement that comes to mind is to use a micrometer, and stick the shaft through the braze-on. This allows you to measure the thickness of the tube on the side opposite of the braze-on. There are a couple of issues with this technique that come to mind... and probably many that don't....

1. the interior of the tube is concave and the micrometer shaft has a flat end. You'd have to stick something convex (like a ball bearing) onto the end of the shaft.
2. the shaft on my 1" mic is a bit over 5mm, and the shaft on my 2" mic is a bit over 6mm. Not going to fit into the braze-on. You could attach a piece of smaller rod to the end of the mic shaft, though. Might be a bit fiddly. The length of the rod could be subtracted from the final measurement to yield the tube thickness.

Just some early morning thoughts...

Steve in Peoria

The braze-ons are open at the bottom, so you have direct access to the tube:



You would place something like a thick nail in the hole, measure the height of the nail starting at the bottom of the tube, then subtract the height of the nail on its own. That would give you a wall thickness including the paint. If it is a 28.6 tube, then measure the outside of the tube, subtract 28.6 and divide the result by 2 - that's your paint thickness on one side.

Most of the Formula tubes were "superset", which was a 1/.7/1 downtube like SP with SL .9/.6/.9 top tubes. Stays depended on the model level.

Champion #2 is pretty much the same as SL, so a lighter downtube than SP.

The investigation into the minute specification details of pedestrian volume manufactured frames is even if comprehensive and accurate, of only of esoteric value.
the series produced lugged steel frame is gone.

it is going to be just less effort and work to purchase an example and make one’s own assessment.

there is some merit perhaps to weighing a bare frame and fork, easy enough to do, but only if noting the frame size and basic dimensions. After enough measures perhaps a trend can be found.

Some years back Reed Kennedy came up with a method for using an ultrasonic measuring device to reliably estimate tubing thicknesses. His spreadsheet is here

https://docs.google.com/spreadsheets...ARDJWyGps/edit

The only thing I've ever tried is using an Endoscope to look inside the tubes for rifling and such. Can also help spot any rust and tell you if the tubing is seamed or not. Not a lot of help is most cases but some.

FWIW, the Formula One tubing label does not say "Superset".


My Tange #2 framed bike rode nothing like a couple of SL tubed bikes in same frame size. Maybe geo was to blame.

Whether they say superset or not, this SL/SP style mix was used throughout the line.

You cannot tell the difference between SL and #2 and 022 by feel. So it is something else.

I think lug weight differences will offset any difference in tubeset weight.


The reason to do it would be to have a better idea how different frames are likely to ride, since diameter and wall thickness are the only parts that determine ride from the tubes, while alloy and seams do not.

From there you could make some educated guesses about the specific tubes selected.

I was a little disappointed how short the list of tubes was in the ultrasonic tube measurement project. Tbh, that told me people lost interest. You have to get the speed of sound right, but I'm not sure how much it varies among frame steel. The cheap thickness measuring devices won't do it, you need something that knows it might see paint and look for multiple returns because tubing is thin.

I would like to be able to measure new tubes, but not enough to set up my ultrasonic system.

That has long been my belief, as well.
But I'm not sure if it's 100% accurate for every (Italian made) Bianchi for all time, but widely enough repeated to make it sort of "common knowledge"...and so that's knowledge FWIW!

There are a couple of twists to knowing tubing thickness. 1st is manufacturing inconsistencies. I used to always weigh Columbus SL chain stays because they varied between 140 to 175 grams. I weighted them to find equal weight pairs and also to put lighter ones with lighter riders and so forth. 2nd manufacturing spaces and actual specs are often not the same. For example old SL had .9/.6/.9 wall thicknesses in their top and down tube. While generally correct, they weren't exactly those dimensions. So when looking at a tubing spec chart, it might appear that different brands had the same wall thickness for a particular model but I'm reality were a bit different.

Columbus tubes weren't even very concentric when I measured them, in the '80s. As I mic'd the tube different places around the circumference, I found different thicknesses, with a max on one side and a min on the other, like the inner and outer sufaces were truly circular, just not on the same centerline. This was repeatable, not random measurement error. So, on a couple "special" frames, I oriented the miters to put the thickest part of the tube where the forces are highest, as evidenced by where fatigue cracks are most likely to form. The differences weren't enough to make this procedure worth it generally. Sorry I don't remember now how much variance I found, but it was noticeably more than on Reynolds or Tange tubes I measured the same way.

One other framebuilder, whose name you know for sure, told me in a private email that he found the same thing, also back then. I don't know if this has any relevance to tubes made in the current millennium, probably not.

I suggest measuring everything on columbus tubes. I haven't had any that were bowed, but I had some spirit tubes where the seat tube wasn't properly drawn. I guess measuring the seat tube is always a good idea that most builders skip.

When I worked at Trek, I wasn't particularly happy with Reynolds, because their tubes were never the same OD. With the fixtures we used at the time, having a tube that was too small could be a real pain. And sometimes they were too big to fit in the lugs. Seems to me that newer tubes are better, but my old prejudices mean that I don't use Reynolds unless I have to. And their new prices are a little out of hand.

This may be of interest, dave kirk measures tube prior to a build.....

partial quotes

"While it’s true that tubing quality is for the most part very good it’s still possible for a simple mistake to be made that results in failure of the frame."
At Serotta I learned that we needed to confirm specs. Measuring the outer diameter was easy but we also needed to be able to measure the wall thickness of the tube over its entire length, and the location of the butts. Without knowing that we were effectively blind.

I have a butt sniffer, which is basically very long thin calipers that can reach over halfway* down a bike frame tube. I was about to make my own when I googled it and found Farr was selling his at a discount, blowout price really, I couldn't have bought the raw materials to make one for less. They're pretty easy to make though, lots of people have DIY versions. The Farr one is pretty deluxe, but other than looking spiffy, it works the same as even a barely-competent DIY would.

*They could be made longer, but they only have to reach halfway 'cuz you can flip and measure from the other end. (Duh.)

They can be used on a seat tube of a finished frame but only from the top, so you won't be able to reach the butt at the bottom unless you make it longer. They're usually used only for checking raw tubes before tacking up the frame.

Years ago I was at one of Peter Weigle's French Fender Days, a fellow brought a device that did exactly this. Of course, you'd have to cut frame in half to check how accurate it was. I do remember it was something like a $5k tool.

I kick myself for not buying one of those when I saw it.

Try it and get back to us.