Lazyass

After putting over 5000 miles on a hydroformed aluminum frame I am completely sold on the process. The ride quality and stiffness are better than any bike I've owned, and I've owned a lot. I do not see any advantages carbon has, except for a slightly lighter weight, and yes I've owned one. I'm not here to debate that, but I am curious as to why there are no hydroformed steel bikes. I love steel, it's what I started out on and I'll always have a steel bike. But the thought of a hydroformed one gives me a thrill up my leg (as an unwise man once said). I know steel has been hydroformed in other applications, but what's up with bikes? Would it cost more to do than aluminum? Any guesses?

Bob Dopolina 

I don't think the process works on steel. Alloy is much softer. This is only speculation, however.

Campag4life

First, your thesis of a hydroformed Al bike riding as well as a carbon bike is flawed. One of the best engineered Al bikes on the planet is the Spesh Allez Smartweld with very asymmetric hydroformed sections throughout that closely emulate a carbon tube frame shape in fact. First time you look at a Allez it looks like a carbon bike. The Tarmac rides noticeably better.
Will some be OK with a hydoformed Al bike? Absolutely. The CAAD10 also rides decently with less hydroforming. Al bikes have come a long way but lets be clear. The Tarmac for those know, rides noticeably better. I know this first hand being around racers that ride each.

As to hydroforming Steel. Hydroforming is based upon pressure and plastic deformation without fracture. Al has much lower yield strength and much lower modulus of elasticity compared to steel. This can be worked around somewhat...but not without the weight aka material density getting in the way. So far, I haven't seen any hydroformed steel bikes...hydroforming creating a differential section modulus which divorces lateral from vertical bending....providing ride compliancy but stiffness when applying a big load to the pedals.

bikemig 

So just to be clear. The OP has a subjective opinion as to the ride quality of a hydroformed AL bike and that subjective opinion is flawed. That's good to know.

RNAV

Breezer has a hydroformed steel road bike.

rpenmanparker 

This is the definitive answer. @Campag4life has not (as at times in the past) mentioned the lack of ability to lay up metals with regard to directionally differential stiffness and strength characteristics as another reason that Al cannot truly match well designed and executed carbon fiber, and that is even more reason for the differences.

rpenmanparker 

Nominally yes, but just looking at the photo, I don't see much shaping of the tubes. That leads me to believe the hydroforming is very minimal.

bbattle

Any metal can be hydroformed but the pressures necessary are quite high for steel and Ti.

A well made, triple hydroformed aluminum frame or a budget level carbon frame; which would you choose if you had a $2500 budget?

It's unfair to compare the Allez to the Tarmac without taking cost into consideration. ($975 versus $3000)

sced

It's all subjective / hearsay. There is no one definition of "ride quality" and nothing that would pass muster as meaningful data that backs up anybody's assertions about it. The space of possibilities is infinite, making this a "how many angels can fit on the head of a pin" exercise.

The much higher tooling and processing costs associated with hydroforming steel bike frames relative to market demand would seem to make it financially too risky - why it isn't happening.

CliffordK

The notes I'm seeing indicate that hydroforming is used in the auto industry with steel, although there are apparently two different processes, tube hydroforming, and sheet hydroforming. Perhaps the sheet hydroforming is the common process with steel in cars. Nonetheless, either process should work with steel. (CroMo?)

Colnago and other manufactures had experimented with unique steel tube shapes in the 80's and 90's.

I think the biggest limitation is that no cutting edge research is being done with steel frames now. It is all Aluminum and CF.

chaadster

WTF does that mean??? Nominally? It has hydroformed tubes.

It is an expensive process to apply to steel, particularly for the machine costs. Two years ago, there were only two factories able to produce hydroformed steel tubes in the world, both in-- surprise, surprise-- Taiwan. Breezer claime in '12 theirs was the "first and only" hydroformed steel road frame in existence. I don't know if that has changed.

So, it can be done, and it can produce a light, rigid steel frame; I have one of the Venturis and can attest to that first hand.

The questions, then, revolve around why it isn't more common, and I think the answer is simply that it's new tech being applied to out-of-vogue material, and the relative costs to gains are too high for most to indulge when they're already elbow deep in carbon that's also highly fashionable. HF steel just doesn't make sense in purely practical terms, but for a company wanting to make a philosophical statement and with the means, well, that explains the Breezer, anyway.

chaadster

Exactly.

rpenmanparker 

I don't disagree with anything you said. My comment was simply an observation coupled with surprise. Hydroforming isn't a prima facia quality booster. It is done for a purpose, i.e. to impart shapes and cross sectional profile details to bicycle tubes that cannot be accomplished with traditional extrusion-over-a-mandrel techniques. It only has value relative to its cost if it produces such effects. Okay, so what I was saying was, where are those shapes on the Breezer tubes? I don't see them. Hence my use of the term nominally. Maybe a bad choice of words, but I meant the process was named hydroforming, but the result doesn't look like hydroforming was used. Why was this exotic process employed if there is no evidence of the effect? Well, perhaps there are details on the inside of the tubes that needed hydroforming to be produced. I don't know. Can you shed some light on this? Another explanation is that the limits of steel hydroforming only allow minimal shape, etc. effects to be realized. That is what I was really suggesting. Just guessing of course.

chaadster

It's a very strange conclusion to jump to that Breezer is saying they're HF tubes when they're not, especially when you've never seen HF steel, never seen the bike, and only reference HF alu.

I think a more critical consideration would have been to ask, "Wow, compared to the aluminum frames I've seen, the Breezer really has a lot less shaping. Is that a limitation of what can be done with steel, or a manifestation of how little shaping it really takes to make an awesome steel frame?"

Look up Breezers D'Fusion tubesets, and you'll learn the HF shaping he's designed into this tubeset is derived from his alu tubesets, which aside from being larger and easier for the indiscriminate eye to grasp, share the same D shaped tube ends to enhance stiffness of the front end. None of his bikes are radically shaped, which I'd guess is the more common conception of HF. Those shapes may work, they may even be better, or they may be just for show, I dunno, but I do know the D'Fusion shaping really seems to work in the steel while preserving an essentially classic look, which I *deeply* appreciate.

Lazyass

It does work on steel. Harley Davidson does it. I'm sure it takes much more pressure to shape the tubing than alu.

It's not a "thesis", it's an opinion. What you think of that opinion means nothing to me. And I stated I'm not here to debate that so start drama elsewhere.

hueyhoolihan

they probably just plugged all the holes, shoved a hose up the downtube, turned on the faucet and called it good.

rpenmanparker 

That is a fair assessment. I asked you to explain why the hydfroforming wouldn't be more obvious, and you offered a hypothesis. Your other one about the limitations of steel is important also. In order retain a semblance of light weight and avoid tube denting, tube size has to be kept moderate and that includes the size of every part of the tube. Extreme shaping means an extreme differential in the size of a tube at different parts along its length. Steel shaping might be limited by the range of wall thicknesses and diameters which attention to weight and dent resistance allow. This would be consistent with the maximum diameter useful in a more traditional butted steel tube which provides both performance and weight advantages. As wonderful a bicycle frame material as steel is, and I am a steel guy from way back, it is generally recognized that it will always be deficient to aluminum in its ability to relatively upsize tube diameter and downsize tube gauge in order to maximize stiffness and minimize weight.

That Breezer is a beautiful frame. I am glad you like it.

rpenmanparker 

There is something vaguely perverted about that proposal, but it certainly has merit.

hueyhoolihan

hueyhoolihan

that's what i was going for... vaguely perverted and meretricious.

rpenmanparker 

That's my kind of man!

chaadster

Well given that every material is limited in those ways, it again goes to a lack of experience with the possibilities of hydroforming that make you think it's not "obvious" on the Breezer. I mean steel is not aluminum, so why should it look the same?

Does hydroforming look like something? No, it doesn't, it's a process to achieve a design objective, and depending on what the criteria are and the substance being formed, it's only reasonable to expect that the properties of different materials in different applications should force the results to appear different.

The Breezer obviously has shaped tubes; why they're not more extremely shaped, I don't know, but I think the reasonable and most likely answer is that they don't need to be. All the wild-assed guessing stuff I'll have to leave to you; I don't know enough about materials properties, engineering, or the HF process to hazard any rooted-in-reality insights, nor am I'm terribly interested in indulging meaningless hypotheticals.

chaadster

Given that meretricious also means having the characteristics of a prostitute, that comment is a little awkward...

rpenmanparker 

At least he has style.

rpenmanparker 

Of course they need to be. The problem is they can't be. Not because hydroforming can't do it, but because either of two things would happen. Either the wall thickness will be sufficient, and the weight of the frame due to the larger diameter will be too high to meet the design goals, OR the wall thickness will be insufficient, and the tubes will be prone to denting. So the hydroforming has to be applied to smaller diameter tubes than with aluminum where the effects don't APPEAR to be as great. That is how steel suffers in comparison to aluminum. By the way, Ti is between the two in this regard. That is why aluminum has become the premier metal frame material, followed by titanium and then steel.