Was mid 90's Colorado Concept Tubing Reynolds 531?

[Slowhand]

Hi,

I'm looking at purchasing a 1997 Atlanta frame. I've seen that in 1999 the tubing became heat treated. The fork is 531 and I'm wondering if the Colorado Concept 2 (or 3) for that matter made by Reynolds at the time (96-98) was specially formed 531, or something else?

Anyone have an idea?

Thanks!

[AndrewS]

I have no idea, but think this is an interesting question.

I would not be surprised if the tubeset was a blend of 531 and Reynold cromoly, rather than a specific 531 or other numbered run.

[jeo99]

I do not think this was the case. In-fact I believe Dave Kirk made that point not too long ago in a forum discussion.

:beer:

[AndrewS]

Made what point?

Custom tube sets by frame builders are often blends of different models or even brands of tubing. What did Dave say about Colorado Concept tubing? I missed it.

[oliver1850]

.

[David Kirk]

One thing to keep in mind is that the alloy of steel used has no bearing on how stiff the bike was. None. The diameter of the tube is what counts and increasing the diameter of the tube even a little bit will have a large effect of the tube stiffness. Practically speaking at the steel alloys used have the same stiffness if they are drawn into the same size and wall tubes. From water pipe to 953 - if the diameter and wall are the same so is the stiffness.

The Colorado tubes were 1 3/8" dia. at the BB making them a full 1/4" larger than the 'normal' tubes at the time. This is a huge difference and made the tubes much, much stiffer than the norm and it had nothing to do with the alloy (Nivachrome or 531 or Prestige....etc).

dave

[William]

One thing to keep in mind is that the alloy of steel used has no bearing on how stiff the bike was. None. The diameter of the tube is what counts and increasing the diameter of the tube even a little bit will have a large effect of the tube stiffness. Practically speaking at the steel alloys used have the same stiffness if they are drawn into the same size and wall tubes. From water pipe to 953 - if the diameter and wall are the same so is the stiffness.

The Colorado tubes were 1 3/8" dia. at the BB making them a full 1/4" larger than the 'normal' tubes at the time. This is a huge difference and made the tubes much, much stiffer than the norm and it had nothing to do with the alloy (Nivachrome or 531 or Prestige....etc).

dave

One of the many reasons I heart this place and the people in it. :cool:



William

[AndrewS]

I wasn't commenting on the alloy choice itself, just that it was probably not an off the shelf tubeset. A blend.

[Slowhand]

Thanks everyone. I'm new to the forum, but I've browsed it several times and appreciate the tone and high quality of discussion.
Ok, I'll lay my cards on the table. I'm just a recreational rider (used to ride pretty long miles, have had some physical issues, but love cycling as much as the next guy) and I'm thinking that my 1983 touring bike can't be the zippiest ride around. I ended up with this bike after determining my Italian steel racing bike from the 80's was too small. So there's this beautiful Atlanta frame for sale in my size, and with the threaded fork I can get my bars up high like my bad back needs, etc. This is actually a big deal, as that's hard to do with modern threadless forks.
But here's my dilemma: is this older steel frame really going to make any significant difference? It will probably save about 1.5-2 lbs off the current rig. Would a newer steel frame be significantly lighter (I don't think so from all that I've read: it seems a steel frame is always around 4 lbs, with some exceptions) or ride any "better"? If I just hang my old parts on it, does it make any sense, or would it only make sense if I go hog wild and lighten up the gruppo (I have 105 quality stuff from 80's-90's)?
Well, there you go, I'm struggling with this, because I'm not the kind of person who buys and resells stuff frequently. Can't really try it unless I buy it.
Also, what seems to be a fair price for a 1997 or so Atlanta in very good shape?
Thanks for any input!

[MadRocketSci]

One thing to keep in mind is that the alloy of steel used has no bearing on how stiff the bike was. None. The diameter of the tube is what counts and increasing the diameter of the tube even a little bit will have a large effect of the tube stiffness. Practically speaking at the steel alloys used have the same stiffness if they are drawn into the same size and wall tubes. From water pipe to 953 - if the diameter and wall are the same so is the stiffness.

The Colorado tubes were 1 3/8" dia. at the BB making them a full 1/4" larger than the 'normal' tubes at the time. This is a huge difference and made the tubes much, much stiffer than the norm and it had nothing to do with the alloy (Nivachrome or 531 or Prestige....etc).

dave

who needs textbooks anymore?

http://en.wikipedia.org/wiki/Beam_theory

takeaway: for a cantilevered beam, "stiffness" (load divided by deflection, at free end) is proportional to the beam's second moment of area, proportional to young's modulus (constant for all steels), and the length of the beam cubed

subtakeaway: shortening/lengthening tubes has a large effect on stiffness

http://en.wikipedia.org/wiki/List_of_area_moments_of_inertia

takeaway: for a thin walled circular tube, area moment of inertia scales with the 3rd power of average tube diameter, and linearly with thickness

therefore, for a tube diameter of 1 3/8" to 1 1/8", similar thickness, the stiffness ratio is 1.8...i.e., the larger tube is almost twice as stiff.

Note: This does not apply to colorado concept tubes exactly as those tube diameters vary along its length. It applies to constant diameter tubes.

Note: there are similar equations for beams under torsional loads and shear stress...

[Mark McM]

takeaway: for a thin walled circular tube, area moment of inertia scales with the 3rd power of average tube diameter, and linearly with thickness

therefore, for a tube diameter of 1 3/8" to 1 1/8", similar thickness, the stiffness ratio is 1.8...i.e., the larger tube is almost twice as stiff.

... and from further derivation, we can see that, while a tube increases bending stiffness with the cube (3rd power) of tube diameter, its weight increases with the square (2nd power) of tube diameter. However, if you decrease the tube wall thickness as the diameter increases so as to keep the total weight constant, you find the the stiffness increases with the square of diameter for a constant tube weight.

[MadRocketSci]

... and from further derivation, we can see that, while a tube increases bending stiffness with the cube (3rd power) of tube diameter, its weight increases with the square (2nd power) of tube diameter. However, if you decrease the tube wall thickness as the diameter increases so as to keep the total weight constant, you find the the stiffness increases with the square of diameter for a constant tube weight.

I shall call you....mini-me

:beer:

[William]

who needs textbooks anymore?

http://en.wikipedia.org/wiki/Beam_theory

takeaway: for a cantilevered beam, "stiffness" (load divided by deflection, at free end) is proportional to the beam's second moment of area, proportional to young's modulus (constant for all steels), and the length of the beam cubed

subtakeaway: shortening/lengthening tubes has a large effect on stiffness

http://en.wikipedia.org/wiki/List_o...ents_of_inertia

takeaway: for a thin walled circular tube, area moment of inertia scales with the 3rd power of average tube diameter, and linearly with thickness

therefore, for a tube diameter of 1 3/8" to 1 1/8", similar thickness, the stiffness ratio is 1.8...i.e., the larger tube is almost twice as stiff.

Note: This does not apply to colorado concept tubes exactly as those tube diameters vary along its length. It applies to constant diameter tubes.

Note: there are similar equations for beams under torsional loads and shear stress...

... and from further derivation, we can see that, while a tube increases bending stiffness with the cube (3rd power) of tube diameter, its weight increases with the square (2nd power) of tube diameter. However, if you decrease the tube wall thickness as the diameter increases so as to keep the total weight constant, you find the the stiffness increases with the square of diameter for a constant tube weight.


MRS & MCM...I WANNA PARTY WITH YOU GUYS!!!! :beer:



William :)

[spartacus]

One thing to keep in mind is that the alloy of steel used has no bearing on how stiff the bike was. None. The diameter of the tube is what counts and increasing the diameter of the tube even a little bit will have a large effect of the tube stiffness. Practically speaking at the steel alloys used have the same stiffness if they are drawn into the same size and wall tubes. From water pipe to 953 - if the diameter and wall are the same so is the stiffness.

The Colorado tubes were 1 3/8" dia. at the BB making them a full 1/4" larger than the 'normal' tubes at the time. This is a huge difference and made the tubes much, much stiffer than the norm and it had nothing to do with the alloy (Nivachrome or 531 or Prestige....etc).

dave

Is this Young's modulus E?

[Ken Robb]

To get back to the OP's question: the Atlanta is a dandy ride with classic stage race geometry i.e. stable but not sluggish. It will feel quicker than any touring bike I can imagine. Whether it will really make YOU any faster is for you to determine. I would buy it and put a decent triple gruppo on it since you are probably used to that gearing now. You may not use the small ring as much on the lighter new bike but you'll be more confident knowing it's there if you want it.

I would keep your old bike too and ride it with the fattest tires you can fit for a very different and cushier ride than your new "racy" Atlanta. It will make a fine errand bike, unpaved road bike, and maybe you'll want to tour someday too.

It's hard to put a value on the Atlanta without all the details and pix but maybe $400 for frame/fork/headset and $800-900 for a nice complete bike with 9spd triple 105 or better gruppo is what I'd pay.

[Slowhand]

Thanks Ken. Your reply makes a lot of sense, and echoes some thoughts I was having.

[bikemoore]

I have an Atlanta with threaded steel fork and I highly recommend it. Quite frankly, I think the Atlanta is one of the best steel bikes ever made. Its balance of stiffness, ride quality, handling, weight, looks, is just right for every kind of road riding there is. If you have access to a nice Atlanta that fits...buy it.

[spartacus]

I have an Atlanta with threaded steel fork and I highly recommend it. Quite frankly, I think the Atlanta is one of the best steel bikes ever made. Its balance of stiffness, ride quality, handling, weight, looks, is just right for every kind of road riding there is. If you have access to a nice Atlanta that fits...buy it.

I wonder how the Atlanta compares to the Coeur d'Acier (all steel version)?

[MadRocketSci]

I bought my used '97 atlanta frame/fork/hs in 2003 for $425. I liked it a lot...it did feel a bit heavier than a modern frame, but for bad roads it was actually a good thing...plowed right through them esp w/25mm tires. Frame was about 4 lbs, fork maybe 2 lbs?

It was a quicker steering bike...due in part to the 55 mm of trail (73.5 HTA and 43 mm rake). Other bikes I've owned have more towards the 59 mm trail (73 HTA). I liked the Atlanta's handling better. IIRC this applies to the '97 model but not to some subsequent years, which I think went to the 73 degree HTA. Not sure when that happened.

[MadRocketSci]

William, any time bro....geek on!!!

[Louis]

Is this Young's modulus E?

Yes, E is a material property that is about the same for all steels and what defines how stiff a given amount / geometry cross-section of that steel will be.

Different steels can handle different stresses in different ways, so in some cases you can get away with less steel for the same loading, but stiffness would be affected.

E is always about the same, but the various strength and fatigue properties vary from steel to steel.

[jeo99]

I have an Atlanta with threaded steel fork and I highly recommend it. Quite frankly, I think the Atlanta is one of the best steel bikes ever made. Its balance of stiffness, ride quality, handling, weight, looks, is just right for every kind of road riding there is. If you have access to a nice Atlanta that fits...buy it.

+2 on the Atlanta. I like mine so, had it coupled and use it for all my traveling!

:beer:

[swg]

I have an Atlanta with threaded steel fork and I highly recommend it. Quite frankly, I think the Atlanta is one of the best steel bikes ever made. Its balance of stiffness, ride quality, handling, weight, looks, is just right for every kind of road riding there is. If you have access to a nice Atlanta that fits...buy it.


+3 on the Atlanta. Plus you get one of these.

http://forums.thepaceline.net/attachment.php?attachmentid=74031&stc=1

[oliver1850]

.

[Slowhand]

Good stuff, thanks everyone. Well, I did settle a question: will a modern steel bike feel significantly quicker/livelier than my current touring rig? Yes, it will. Here are the details for those that care: I rode a Soma Smoothie (Tange Prestige) with Tiagra 9 speed, weighing in at 23lbs or so, and another steel bike with Columbus Zona and carbon fork, and 105 and Open Pros, weighing in at 21 lbs. Both were nice, I really liked the Smoothie, it rode great and could fit me with it's extended head tube and a long steel fork. Both felt faster enough to definitely warrant the upgrade. The Smoothie ES, the more sport tourer version with the same tubing felt significantly more sluggish to me, which was surprising. It was a bigger size too. Somas sell, frame and fork, for about $475. I think it's a great value.
The Atlanta should ride at least as well as those I would imagine. I'm thinking maybe get the Atlanta, get a few modern major weight saving/performance parts upgrades like a 105 compact crank and 10 speed brifters/cassette and I'd have a great bike.

[AndrewS]

Your 1983 touring frame probably has a bare weight near 6 pounds, so even from a weight perspective the Serotta will be an improvement.

I would also expect the geometry to make for an even more exhilarating ride than the nice Soma without any loss in comfort. Racey bikes just feel like it.

I don't think you're investing in old technology as much as tried and true. IMO: Get the Serotta.

[oliver1850]

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