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Old 12-17-14, 02:01 AM
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verktyg 
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There are several overlaping themes here.

1. I mentioned Bianchi Formula 2 tubing in relation to my 1988 Bianchi Giro which has Columbus "FORMULA" decals on the fork blades. The Giro was an upper mid-range model in 1988.



2. I was also talking about Tretubi frame decals used on a lot of other brands of bikes as well as Bianchis. Many of those lower mid range bikes had unknown tubing in the forks and rear stays.

Originally Posted by armstrong101 View Post
What I meant to say in my post was that I had always thought Tretubi meant the 3 main tubes (not the entire bike) was made of Cromor-caliber stuff.
There are lots of opinions as to what Bianchi Formula 2 tubing was made of. The seat tube decals say PRODUZIONE COLUMBUS meaning "produced" by Columbus. The decals go back 25-28 years and the original opinion was that Formula 2 was a mix of Columbus SP and SL tubes.

Until this thread I'd never seen any mention that Bianchi Formula 2 was anything other than a mix or SP and SL tubes. I commented above that it was an interesting possibility that Formula 2 could have been something like Chromor or one of other mid range Columbus tube sets.

Originally Posted by armstrong101 View Post
As you mention, the seat tube sticker implies the fork is not made of Columbus. But I haven't always been particularly sure about that. The Formula 2 fork sticker says words like Columbus, fork, tubing, and no mention about Tretubi (look it up, as I don't have the sticker nearby). In isolation, looking at just the sticker on the fork, you'd be convinced the fork is made of Columbus tubing. So it opens the possibility that the 3 main tubes are Columbus, but so is the fork (assuming the seat tube Tretubi sticker is referring to the frame ONLY, and not the fork, which is certainly conceivable. Again, I'm saying the associated fork sticker for Tretubi leaves open the possibility that it is made of Columbus tubing (or at least, makes the issue ambiguous).
I said nothing about forks in relation to Bianchi Formula 2 tubing.The discussion was about "Tretubi" main frame decals. If a decals says Columbus, Reynolds, Tange or whatever, it's a pretty good sign that a frame from a major manufacturer is made with that tubing. Those tubing makers jealously guard the use of their brand names. Over the past year, Reynolds has gone as far as getting eBay to stop listings for replica Reynolds decals.

All of the Bianchi bikes made with Columbus Formula 2 and Columbus Special tubing that I'm aware of had matching decals on the forks.



Originally Posted by armstrong101 View Post
Regarding tubing manufacturing, what is a "seam"? (sorry, newb here)
Please see my post above. It shows different methods for producing steel tubing.

Originally Posted by armstrong101 View Post
So basically, based on what I've read on the stickers and in places, I've always considered a Bianchi Formula 2 Tretubi frame to have 3 main tubes that were basically Cromor level, and a fork that may possibly be of Columbus tubing also. I never envisioned a Formula 2 Tretubi as having SL tubing, given how mass-produced those low-mid range bikes were.
Bianchi used the same Formula 2 frames on several different models - those were mid range bikes - 2 or 3 models down from the top.

Originally Posted by armstrong101 View Post
All this said, I believe that these differences in tubing are secondary to the actual manufacturing process of the frames themselves. If we consider that almost fully-blinded experiment in the 1990s printed in one of the big cycling journals (the Magnificent 7), given that the riders couldn't distinguish the best material from the worse one, it tells me technique in frame manufacturing significantly exceeds tubing in terms of importance WRT bicycle riding quality. I say this because "everyone" can tell a high-end Bianchi rides better than a low-end Bianchi, but given that, by themselves, tubing cannot be distinguished amongst identically-made bicycles, it implies that it's the skill/technique in the manufacturing process that distinguishes an average bike from an excellent one.
NO! All things being equal, it's the wall thickness of the tubing that makes a difference in ride. Stronger high alloy steels allow for thinner tubes which are also lighter. Bicycle frames and wheels are dynamic not static - they move and flex in use. A lighter frame will absorb more road shock.

BTW, the current cost difference between low quality steel tubing and 4130 chrome-moly tubing (which Columbus SL, SP Chromor and other types were made from) is is only 20% to 30%...

verktyg

Chas.
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Last edited by verktyg; 12-17-14 at 01:36 PM.
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