Aside from the expected Columbus, Reynolds, etc tubing, Serotta had/has his own. I see C3 and C4 on Serotta Colorado stickers and wonder how they compare to something like SL or SLX.
Inquiring minds, etc
Thanks

BTW my friend doesn't care

My guess is that Colorado originated with the shapes of Columbus MAX tubing, with some personalization.
Eventually the claim was that Colorado was not a tube type, but the shapes.
Found this graphic a while ago from an Ebay vendor:
I've got #1, #2 and a CC in red....

"Collect them all! Trade with your friends!"

Colorado tubing is cone shaped, and was made for Serotta out of whatever preferred alloy Columbus, Reynolds, Tange had available at the time.

So it is a shape designed by Serotta and made by a tubing maker to that spec. It is not shaped like other tubing Columbus ever sold. The only thing I've seen like it is the conical swaged tubing Litespeed made into one version of the Basso Gap Ti.

Serotta had a batch of frames made with True Temper tubing that had failures. Ben then went to R.P.I. (Rensselaer Polytechnic Institute) in Troy, NY and worked with them to develop his own tubing design Colorado Concept.

I'm not really very adept at phrasing questions.
I was aware of the different shape stuff. I am curious about what the designation signifies. Do C3 and C4 have different shapes or do they differ in tube types and/or wall thickness, or ... ?
That of course presumes that there was a reason for the different designations.

Thanks

I have the impression that the difference in c3-c4 is the metallic alloys, or should I say i don’t know. I have the Concept in Reynolds and Prestige. The Prestige is a tighter than Reynolds. Both will have less flex at the bb than sl and slx.

They are different in small dimensions - like the butting thickness, alloy and location of the swaging. Just like SL and SP are similar but SP has thicker wall dimensions. In Serotta's case the changes were usually generational, and newer tubes were "better" by being lighter. But they also had lower cost versions of Colorado tubing in some years that might be slightly thicker than the most premium version. Like this 1999 catalog has new versions of C4 and C3 for the CSI and Atlanta models.

These also aren't just simple tubesets - they would use different dimension tubes for a C3 bike for a large rider and someone small. So there is never going to be CC chart like there is for a tubeset like Columbus SL. It is taken on faith that if you buy the most expensive steel bike that year with the highest numbered tubeset that you are getting the highest performing tubes.

I would expect most CC bikes to ride more similarly than different, but the weight will vary.

https://www.retrobike.co.uk/gallery2/d/15544-2/1999.pdf

That's pretty reasonable. Innovative custom builders don't have any need for "standard" anything. I was sorta curious in regard to an Atlanta that I was interested in.
Many thanks
Charlie

My Serotta Atlanta has this tube decal




When I bought the frame and fork a couple years ago, i was told it was a 98. I have been very happy with it.