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COLUMBUS NEMO 747 Tubing !


Columbus logo

For some time we have been working with the Columbus' engineers, developing a new steel tubing for our Countach and the Mondonico Futura Leggero frames. We wanted to take these frames from being semi-pro to full-pro without changing the price. It's always easy to improve the specs of a bike: just make it cost more. We wanted to make these frames much, much finer without charging a single penny more.

First, a short explanation: Torelli /Nemo 747 tubing is made by Columbus out of Nivacrome, and drawn down to only 0.4mm, as thin as virtually any tubing in the world. Frames made of tubing of this quality should (and do when sold by other makers) cost twice what the Torelli Countach and Mondonico Futura Leggero cost.

That's the short story. Now for a fuller explanation so that, I hope, you can appreciate what an extraordinary preformance value frames made of Torelli/Nemo 747 represent.

In the 1970's and 1980's when Columbus' SL and SLX tubing were the state of the art, the top tube was 25mm in diameter and the downtube was 28mm in diameter. The tubing wall was 0.9mm thick at the ends and drawn down to 0.6mm in the center of the tubes. This is what is meant by "double butted". The internal diameter of the tube varies so that the tube is thicker at the joints, where the stress is greatest.

In the early 1990's, steel tubes underwent a small revolution. The top tube changed from 25mm diameter to 28mm. The down tube went from 28mm to 32mm. This increase in diameter allowed the tubing makers to make the walls thinner and still get a stiffer, lighter frame. An additional bonus was the profound improvement in the feel of the bike. The new bikes became more stable (mostly, I think, because of the bigger top tube) and gained a fluid, beautiful feel that is impossible to describe, but wonderful to experience.

With these bigger diameter tubes, the wall thickness at the thinnest part of the tubes went from 0.6mm to 0.5mm and even 0.4mm. Columbus' Brain Oversize (or Brain OS) was 0.8mm at the butt and drawn down to 0.5mm in the center section. People loved the feel of Brain OS bikes, especially since the price was so reasonable.

But.... there was something truly special waiting for those that bought bikes made of EL-OS. EL-OS was 0.7mm at the butt and drawn down to 0.4mm in the center section. First of all, there was a reduction in weight, about 1/4 pound. That's always nice. The biggest bonus was in how the bike felt. Anyone who has ridden an EL-OS bike built by a good builder understands what a supple, beautiful, wonderful bike really is.

The problem was that getting a 0.4mm tubeset bike was expensive. Even now, almost a decade later, there are tubing companies that do not even have the technology to draw a 0.4mm tube. Even though Columbus can now draw 0.385 (a reduction of 15 thousandths of a millimeter from 0.4mm), I think we can safely say that 0.4mm is still the state of the art.

Now you see why we call our new tubing 747. It's 0.7mm at the butt, and 0.4mm in the center, and 0.7mm at the other end. It's made of Nivacrome steel, the super-sophisticated Columbus steel that loses very little strength during brazing or welding.

Now, about the butting. There are two ways that tubing is butted (made thicker at the ends). One is the traditional way, A in the diagram below. The tube gets thinner symmetrically, with an even taper until it reaches the new wall thickness. The other way, called differential butting (B in the diagram below), is the result of intensive study by Columbus' engineers. They learned that there are places in a joint that require a bit more thickness than others. So, the precise shape of the butt reflects that knowledge. The tube is only thicker where it needs to be. Torelli/Nemo 747 tubing is differentially butted.

Differential butting

The chainstays of Toreli/Nemo 747 are 0.7mm taper-guage. When we build bigger frames, we build with 0.8mm chainstays.

When we were done and satisfied with the tubing design, we asked Columbus what we should call it. Being a custom tubeset, it didn't fit in any specific tubing category. They settled on Nemo, being a differentially butted 0.4mm tubing. It differs from other Nemo tubes in that Torelli/Nemo is 0.7mm at the butt, and other Nemos are 0.65mm at the butt.

How does this fit in with the other Columbus modern oversize steel tubings?

Brain OS (0.8-0.5-0.8) is no longer in the Columbus catalogue. However, they do draw it upon request for some builders. For some very big frames, it can be useful. It was replaced by....

Zona (0.7-0.5-0.7). In order to offer a tubing only 0.7mm at the butt, Columbus developed a reduced price Nivacrome that is 1000 Newtons/square meter tensile strength. This compares to the 900 used in Brain OS (and old SLX) and 1200 used in EL-OS, Genius, and our Torelli/Nemo 747.

Neuron (0.7-0.5-0.7). This is a very sophisticated tubing, much finer that one would guess from the 0.5mm wall thickness. Columbus pulled out almost all the stops to make a lightweight 0.5mm tubing, using zone butting, elliptical butting, the works. The result is a tubing that is lightweight, yet very stiff. Mondonico continues to offer frames made of Neuron because it makes a good, stiff, light frame. This tubing still has a very devoted following among serious steel frame lovers.

Genius, EL-OS. (0.7-0.4-0.7). These sophisticated tubes are comparable to Torelli/Nemo 747 in the front triangle. They exceed Torelli/Nemo specification in the rear triangle. These tubesets have double-butted chainstays that are drawn down to 0.4mm. We were not able to offer that in our tubeset and keep the price as low as we wanted. EL-OS is no longer in the Columbus catalogue, but Mondonico has it drawn for his EL-OS monostay. The longer traditional butts of EL-OS offer some performance advantages. The slightly greater mass at the head tube joints make the front end of the frame a bit more stable, or as one Italian said, "robust".

You can see that Torelli/Nemo 747 is a fine a tubing as any rider might desire. For 2001, Torelli will use it in the Countach OS frames, and Mondonico is going to build the Futura Leggero with it. These are now full-pro frames, that are superior to most frames available at any price. Yet, they remain priced in the semi-pro neighborhood.

I just weighed a new 54 cm Torelli Countach TIG: a little less than 3 1/2 pounds. Why lose the beautiful resilience of steel? At this weight and price you can have it all.