# US Hydroforming?



## discodave (Jan 12, 2004)

So I was thinking the other day why we don't see more hydroforming of aluminum tubing on US made bikes? Is hydroforming one of those things that is just for more aesthetic value than actually increase in strength? I am assuming that hydroforming is a significant investment that only large manufactures like Giant and Merida can afford. But it seems like Sapa being a huge aluminum extruder as well as frame manufacture could provide guys like Turner, Knolly, and Titus with hydroformed tubes. Sometimes US built bikes look a little off the back aesthetically . But maybe thats a good thing.


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## Vlad (Feb 7, 2004)

In my opinion, US built bikes look better than the tweaked, twisted, squashed and crumpled frames that come out of Taiwan, which are then made even worse with disgusting graphics.


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## CBaron (May 7, 2004)

Its happening...


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## SuspectDevice (Apr 12, 2004)

Those tubes are formed in Asia.


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## Mark Landsaat (Jul 24, 2007)

Well, there's a difference between hydroforming and mechanical forming. The tubes on the Knolly frame and the Titus frame can be formed mechanically (Tapering and Press molds). Hydroforming those tubes would be a waste of money. Specifically because mechanical forming is a much more economical manufacturing process. The tooling cost for mechanical forming is a fraction of the tooling cost for Hydroforming.

In my opinion most tube shapes that work well from an engineering point of view can be made by mechanical forming. A typical example of form follows function.

If tube shapes are hydroformed and very elaborately shaped I would say that a lot of that is driven by aesthetics. Just my opinion, others may disagree.


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## SuspectDevice (Apr 12, 2004)

Mark Landsaat said:


> Well, there's a difference between hydroforming and mechanical forming. The tubes on the Knolly frame and the Titus frame can be formed mechanically (Tapering and Press molds). Hydroforming those tubes would be a waste of money. Specifically because mechanical forming is a much more economical manufacturing process. The tooling cost for mechanical forming is a fraction of the tooling cost for Hydroforming.
> 
> In my opinion most tube shapes that work well from an engineering point of view can be made by mechanical forming. A typical example of form follows function.
> 
> If tube shapes are hydroformed and very elaborately shaped I would say that a lot of that is driven by aesthetics. Just my opinion, others may disagree.


I couldn't agree more.


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## junktrunk (Apr 17, 2010)

Who cares, so long as it gives the strength, weight, durability, and ride characteristics the designers are looking for?

Most of the tubing for bikes is Taiwanese. Hell, Easton's facility is in Taiwan now for a long time. The availability simply isn't here for such complex forming, and partly because energy costs are very high. Forming tubes costs a lot...


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## Mark Landsaat (Jul 24, 2007)

junktrunk said:


> Who cares, so long as it gives the strength, weight, durability, and ride characteristics the designers are looking for?


I care. Hydroforming is a fast high-strain forming process. in order to prevent material failure you typically make up for this by increasing wall thickness (more weight). Second, there is no good way to control bladder inflation and this can lead to inconsistent wall thickness.

So at the end of the day most hydroformed tubes may be aesthetically more pleasing than mechanically formed tubes, but end up being heavier than necessary. At that point Aesthetics come at the cost of performance.

This may not be much of a problem on longer travel bikes, but I think you will be hard pressed to find shorter travel XC frames that have elaborately hydroformed tubes and are light weight at the same time.


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## Thor29 (May 12, 2005)

Weird. Personally, I think hydroformed tubes are incredibly ugly. I just swapped my older RIP9 for a new WFO9 and the WFO is way uglier.


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## shovelon (Mar 16, 2006)

Thor29 said:


> Weird. Personally, I think hydroformed tubes are incredibly ugly. I just swapped my older RIP9 for a new WFO29 and the WFO is way uglier.


Could not agree more.


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## junktrunk (Apr 17, 2010)

Chumba is doing hydroformed and they've got some know-how behind them to do it right.


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## TigWorld (Feb 8, 2010)

Mark Landsaat said:


> ... I think you will be hard pressed to find shorter travel XC frames that have elaborately hydroformed tubes and are light weight at the same time.


I think a number of the tubes on the Giant Anthem X are hydroformed. It is a pretty light, stiff frameset.


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## Mark Landsaat (Jul 24, 2007)

TigWorld said:


> I think a number of the tubes on the Giant Anthem X are hydroformed. It is a pretty light, stiff frameset.


Hi TigWorld, I was thinking of that frame when I wrote my previous comment, good call. I think you are correct. I don't work for Giant so I can't know for sure how they manufacture their frame, but based on my own experience I would say three tubes in the Giant Anthem X are Hydroformed.

I think the seattube with the linkage bulge and the uprights for the swingarm were made by hydroforming. See picture.

This was done because hydroforming most likely is the lightest solution to manufacture these tube shapes, and those shapes would be difficult to manufacture using other tube shaping techniques.

However, in my opinion the top tube, down tube, chain stays and seat stays were made by mechanical forming (butting, taper, forming). Giant did a good job with that frame, it is a very light frameset.

I guess the point I'm trying to make is that Hydroforming isn't always the best solution. Depending on what type of tube you are trying to make mechanical forming can be lighter than Hydroforming.


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## junktrunk (Apr 17, 2010)

The best solution also goes back to the accounting and the benefit to energy expended in forming the tube ration has to be accounted for.


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## jager7 (Sep 29, 2008)

junktrunk said:


> Chumba is doing hydroformed and they've got some know-how behind them to do it right.


also asian.


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## Ecogeek (Aug 30, 2009)

Wow looks to be a fair bit of generalising in this thread.
Maybe a little rationalising.
SOME straight tubes may look better.
Some may not.
Some may be stronger. Some may not.
Some hydroformed tubes may be lighter due to allowing the tube to go exactly where it needs to without additional braces/joints etc (like the new Yeti ASR - no more extra welds like on the old two-part straight top tube). Some may not.
Also less welds can mean the frame is cheaper, lighter AND more energy efficient to produce overall. Last time I checked, welding uses a lot of juice too! Less welds also means less errors...
Some may be heavier. Some may not.
Some Taiwanese tubes are better than some US tubes. Deal with it.
Some US tubes are better than some Taiwanese tubes. Hoofingrah!

What is the key word. 
Some.

My Taiwanese KHS (great bike and cheap - I built from frame up) uses straight tubes the frame looks fine but has a NASTY paint job that would disgrace any bike. It would not matter if the tubes gave you a boner cos by the time they put that paint on, it would shrivel.
My Canadian RM Slayer is hand built and welded in Canada - although it may use tubes from the far east. But the formed top tube (hydro or mechanical dont know) is damn good looking. So is the ano finish.
My Titus (also ano) uses straight tubes - and a god-awful looking seat-tube brace. That could have been avoided w formed tubes pos saving two welds and one tube.
But I did not buy it for looks! And it still looks fine except to posers.

Seems pretty obvious that either straight or hydro can be best in various designs and we are all happy with either as long as they are strong, light, reasonably priced and (apparently most important) good looking.

Knolly are Canadian BTW but I do not know where their tubes are from. I do know that their hydroformed tubes make bikes anyone would (should) drool over for both performance and looks (as an almost irrelevant bonus).

Curved tubes clearly allow some design flexibility and therefore some geometry flexibility without sacrificing fit. One would expect all frame-builders to LOVE that idea. Clearly some do love it cos they take advantage.
The only scenario where a builder would dismiss it entirely seems to be if they were already struggling to compete w the far-east and did not want another problem.
And so that is the real issue isnt it. 
If we cannot do it we will tell everyone it sucks and that we dont do it cos our straight tubes are *always* better for everything.
BS.

From another thread in the framebuilding forum from a master. "Your average bike designer doesn't really like being told how to design something or what tubes he should use. He's spent the past 10+ years figuring all that out."
I guess if you are in that boat and figured out all your straight tubes, you do not like formed to come along...
Sorry to anyone this offends.


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## charging_rhinos (Jul 29, 2008)

^^ great post. +1

I personally like hydroforming quite a bit. I work in a place that makes climbing and skiing gear, and we have studied hydroforming for a long time. We went with it for some of our ice axe shafts, and it is simply amazing what it did for the tools. Lighter and FAR stiffer where needed, and less material waste where it wasn't. Super beneficial for us. 

I think people (designers) often get caught up in the whole 'how swoopy can I make this bike look while still being functional' mindset. But I think that if you back off a tad from that line of thought, you can get some real benefit from hydroforming. To me, the major benefit lies in being able to 1) direct forces along the tubing in ways that will allow for less material usage where it isn't needed, and 2) allow for loads to be spread along larger areas of tubing for greater rigidity/leverage (ex: how a top tube will open considerably as it interfaces with the head tube. 

If it's done well, hydroforming can produce pretty consistent results, as far as material thickness and grain structure of the metal goes. It all depends on the raw material and how crazy they try to get the tubing. Some go overboard, but I'm all for the progression of it personally. In the end, we'll learn from it, whether the results are positive or negative. We'll be left with undoubtedly better, stronger and lighter frames. 

Aesthetics is another issue though, so I won't go there.


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