Tubing Q:

[false_aesthetic]

As I get further along in building bikes of a consistent quality. I'm starting to look into various tubing offerings.
I started with straight gauge .028 and .035" then to 8-5-8 and now onto 7-5-7 and thinner.

Today I was looking at butting profiles on a 28.6 Top Tube. 7-5-7 vs 7-45-7. The butts + transitions are the same length in both offerings. The difference in weight will be minimal. There is obviously a price difference. (Zona vs Life).

I'm assuming that since the butting profile, diameter, and basic material (i.e. steel) are the same, there's little difference in ride quality between the two... especially as 1 out of 9-ish tubes. I'm also assuming that Life is a bit harder to file. So for a novice builder like myself, it seems that the benefit for choosing Life is minimal (so existential, I know).

But I wonder, for the master builders, what else would you be "weighing?"

Again, I recognize that this is just a piece of the whole (bike) but as a young-ish product/OPS guy, this seems like one of these SKUs should be eliminated since (from a novice's POV) they're redundant. Obviously it was deemed necessary. And I want to understand why. My knowledge base isobviously lacking.


Thanks!

[Andrew R Stewart]

Why? My thoughts are along the lines of selling hope and dreams. Numbers don't lie (although stats can be damned numbers:) so a simple marketing claim can be made when the product has ever so slight a difference. Andy

[Crowemagnon]

While i don't prescribe wholeheartedly to the McNamara fallacy of the published numbers, i might prescribe to the marketing because i think the tubes are quite different... ive built ~50 bikes, 90% from colombus tubes, and my 2c is that OMNICHROM is definitely different stuff from the 25CrMo4;

It sounds different, it feels different to work, it builds into a bike that feels different to ride
(the tube shapes are also often different, so buckets of salt, though im fairly consistent when choosing diameters)

id like to think the omnochrom bikes 'zing' a little bit more on hard tyres, and they have a more likely whippynes in their feel when handled well at high speed, this means they can wallow around a bit in rough/slow surfaces. and REALLY dont descend well without enough weight on the front wheel.

with my personal bikes, id say the zona bikes accelerate well to 40kph. the life bikes accelerate well from 40kph.

I like to use life for flat-out smooth-surface race bikes for fast & light people (road bikes with road bike brakes, velodrome bikes), and in the top half of bike one step more grippy than that, eg a very sprinty road rider might get a life tt/ss and a BIG zona dt/cs.

I definitely found omnichrom tubes more difficult to work with than the 25CrMo4 early in the peace; i buckled a couple of tubes cold setting mistakes very early on, and cracked a chainstay after crimping it too far. i quickly found a fondness for zona that lasted for the next ~30 frames.

If i'm going to be doing any bending/pressing/squashing tubes nowdays (e.g. i have a fondness for a /quite squished/ flat top tube that tapers back to round at the seat tube) i buy the zona tube. i think they take a set more readily, and this lets me go deeper when forming, to get the shape i want after springback, without such extreme forces and shapes occurring along the way.

[Andrew R Stewart]

Back in the 1980s Bicycling Mag did a comparison article with two different tubing brands (IIRC it was 531 and Col SL, 531 being Manganese/moly and Col being a Chrome/moly). They tried to mimic the tube specs best possible. The same builder made both frames and painted one blue and the other pink, no other markings like stickers. The mag's staff tried to ascertain which was which. Again IIRC, the results were that no rider was able to say which was which with certainty. Granted the differences were less then what you are looking at with current tube choices but the point was made. Steel alloys are so close to their structural performances, Yong's Modulus and such that it is considered, as far as riding quality goes, the various materials perform pretty much the same. Now as far as other qualities like formability (and denting in under this umbrella), hardness (think filing and cutting) and reaction to heat levels and cycles are different.

This discussion is much like what I had years ago when I was into home stereos big time. Then the tape deck offerings were opening up with the classic open reel deck being challenged by both 8 track and cassette decks. It was generally thought that with the narrower track width that the cassette and the 8 track needed for their compact size made their reproduction inferior to the big reel to reel decks and at first this was quite true. But soon the recording head technology advanced and the skinny tape devices were thought to be superior in time. But the comparisons were not on an even playing field. The advances in heads were not applied to the reel to reel decks (or at least not at that time).

I suggest that these discussions about tubing differences in ride quality is much like that of tape recording back then. The field is not level with tubes from each type of material not being offered in the same dimensions and shapes. Nor is the marketing of these materials the same. These days it would be impossible to make two frames of identical specs, one from Zona and the other from Omnichrom. Or one from current 531 and the other from 853. Also if one did make the two frames the mere shaping/diameter differences would make the test not a true double blind one. As your comments prove we know that pre conceived notions can be stronger then actual sensations.

Your comments about forming tubes and choosing Zona is all about hardness, brittleness and such and I agree with this completely. Andy (who just crashed and bent up his 49th frame and now is planning #50 )

Another thought- The 8 track tape width was a better recording design with it's slightly wider tape and thus track widths. But it was the packaging of the cassette that won over in the marketplace. So sometimes mere numbers are out done by more practical considerations.

[Crowemagnon]

Back in the 1980s Bicycling Mag did a comparison article with two different tubing brands (IIRC it was 531 and Col SL, 531 being Manganese/moly and Col being a Chrome/moly). They tried to mimic the tube specs best possible. The same builder made both frames and painted one blue and the other pink, no other markings like stickers. The mag's staff tried to ascertain which was which. Again IIRC, the results were that no rider was able to say which was which with certainty. Granted the differences were less then what you are looking at with current tube choices but the point was made. Steel alloys are so close to their structural performances, Yong's Modulus and such that it is considered, as far as riding quality goes, the various materials perform pretty much the same. Now as far as other qualities like formability (and denting in under this umbrella), hardness (think filing and cutting) and reaction to heat levels and cycles are different.

This discussion is much like what I had years ago when I was into home stereos big time. Then the tape deck offerings were opening up with the classic open reel deck being challenged by both 8 track and cassette decks. It was generally thought that with the narrower track width that the cassette and the 8 track needed for their compact size made their reproduction inferior to the big reel to reel decks and at first this was quite true. But soon the recording head technology advanced and the skinny tape devices were thought to be superior in time. But the comparisons were not on an even playing field. The advances in heads were not applied to the reel to reel decks (or at least not at that time).

I suggest that these discussions about tubing differences in ride quality is much like that of tape recording back then. The field is not level with tubes from each type of material not being offered in the same dimensions and shapes. Nor is the marketing of these materials the same. These days it would be impossible to make two frames of identical specs, one from Zona and the other from Omnichrom. Or one from current 531 and the other from 853. Also if one did make the two frames the mere shaping/diameter differences would make the test not a true double blind one. As your comments prove we know that pre conceived notions can be stronger then actual sensations.

Your comments about forming tubes and choosing Zona is all about hardness, brittleness and such and I agree with this completely. Andy (who just crashed and bent up his 49th frame and now is planning #50 )

Another thought- The 8 track tape width was a better recording design with it's slightly wider tape and thus track widths. But it was the packaging of the cassette that won over in the marketplace. So sometimes mere numbers are out done by more practical considerations.

thanks Andy, reading that now i can see im definitely exploring a tunnel of thought that could've done with some more context;

i 100% agree that it's entirely reasonable to consign notable differences in feel to the tubes being different tubes; different diameters, profiles, wall thicknesses, butts, ect... i think we both believe these things can make big differences; and the differences in feel I'm talking about may be entirely attributed here, with the material correlation being unrelated.

i also want to be clear to Tom that I (as Im sure he and many others do) have chosen those tubes within a process where lots of other decisions influence the feedback someone gets from the bike, ESPECIALLY given that often those other decisions are made entirely with the intent of converging on a specific timbre of feedback (!) ,ESPECIALLY ESPECIALLY because that specific timbre of feedback Im hoping to converge on , is one which mimics the feedback Im hoping the tubes will provide (!!)

Let me also clarify that im prone to a model of thinking that when i say feedback or feel , i mean (as-well as what we usually include), how it looks, how it sounds ect. because i believe these things influence how we perceive how it rides, and how we perceive how it rides, is within this working model, basically whats important.

but before this becomes farcical, i think it was worth mentioning that those two materials are significantly different, and that is worth making at-least an informed, if not considered decision about, even for a working theory. I respect that others who probably know more than me think this doesn't or wouldn't translate to meaningful differences in a frame, but i think if pushed, while i wouldn't stand on a hill and say it absolutely DOES, i would strongly argue that someplace, to someone, it definitely can.

p.s. cmon, thats an easy one; surely nobody thought the blue bike was faster than a pink bike

[Andrew R Stewart]

My only pink bike is my slowest, it's my fixed gear rollers one:) Andy

[steve garro]

“Hell is an idea first born on an undigested apple-dumpling...”


― Herman Melville, "Moby Dick"

Build more / think less

You can't feel alloy composition

I do appreciate your enthusiasm for building, however !!

- Garro.