25Seven

Strategic Application of Carbon in a Titanium Bicycle Frame

Someone asked me the other day about Seven Cycles’ approach to combining titanium and carbon together in one frame.  This conversation occurred, in part, because of our recent introduction of our Integrated Seat Post frame model.

Part of the conversation had to do with the various approaches to combining titanium and carbon together in a single frame.  And why Seven approaches it the way we do.  This is a long complex conversation.  Not one we could cover in one discussion; so we focused on only one facet of titanium and carbon as frame materials:  vibration and shock absorption.

Titanium and carbon are interesting in the context of vibration characteristics because they behave so different from each other.  This difference is one of the primary reasons that Seven offers frames that combine both carbon and titanium—as well as monolithic titanium frames and full carbon fiber frames.

Titanium: The New Wonder Material?

There’s a topic that been coming up more and more at Seven Cycles over the past year or so.  It crystallized for me a few weeks ago while I was giving a technical manufacturing tour to some visitors.  I was walking some or our retailers through our production process; nothing unusual there.  What was unusual was the number of questions regarding titanium.  These weren’t the typical I-already-know-the-answer-type-of-questions that I sometimes hear.  These were real, fundamental questions about titanium; questions that belied both a lack of knowledge about the material and a true interest in understanding the material’s properties, benefits, and uses.

Essentially, the questions and interest struck me that titanium appears to be the new wonder material for those that didn’t grow up with it.  It feels similar to how it was 20-years ago.  I think there are a few obvious reasons that titanium is once again confusing—and alluring—to people; the primary reasons include:

Results of Fire Damage to Titanium—and Other Materials

A good friend of Seven had a really bad New Year’s Eve night.  The house where he and his family were storing a lot of possessions, burned to the ground.  His family is safe and no one was injured in the fire.  The house and all the belongings were not so fortunate; one of those possessions was our friend’s Seven Aerios.

This is not the first time a Seven has been through a fire.  Nor the first time we’ve seen the remains of a Seven post-fire.  In a clinical sense, it’s a very interesting sight; our friend brought us the frame because he was amazed at the results.  Here’s a series of photos that show the surviving skeleton.

First Frame Incorporating Carbon and Titanium

Someone asked me last week about my first experience integrating carbon fiber with titanium in a bicycle frame.  The person thought I was going to talk about Seven’s Odonata frame that we introduced in 1997.  While this was the first carbon frame that we developed at Seven Cycles, it was far from the first carbon frame on which I—and a few others at Seven—worked.  

Twenty Years Ago

My first work with carbon fiber was so long ago that I can't remember some of the dates and details.  It had to be in 1988 or early 1989; I am pretty sure that 2009 will be the 20th anniversary of the first time I got my hands dirty—and itchy—with carbon fiber and all its associated constituents required for frame building.  It was so long ago that I don't even have any photos of those first frames anymore.  

Interview: Tutto Mountain Bike, Italy - Part III

Here's the third installment from an interview I did, for Seven Cycles, with an Italian mountain bike magazine a few years ago.  You can read the first and second parts, too.  Since it was never published in English, and probably no one from the US saw it, I am posting a bit of it here.  

Keep in mind that I was trying to communicate in language designed for non-English speakers.

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Tutto:  “How is the American mountain biking evolving. In the past it was leader:  the top riders, the most important races and events, the best frame designers were American. How is the movement today?”

The Beginnings of the Modern Titanium Bicycle Frame

I was talking with someone at Seven Cycles the other day about the beginnings of Merlin Metalworks.  I dug up this very rare article from an old periodical called Bike Tech.  It was published by Bicycling Magazine back in the 80s.  Bike Tech was an amazing journal—very technical and dense.  It was more of a newsletter than a magazine; the typical issue was 16-pages or so.

The article “Titanium Lives!”, written by Jim Redcay, describes some very early thinking at Merlin Metalworks.  The piece was published in December 1987.  I was lucky enough to have started working at Merlin in September of that year.  I even remember the bike from this article.

Redcay did a very good job of using layperson’s language to explain some of the engineering that went into the revolutionary frame design.  Here are a few quotes for those that don’t want to read the entire article.  Quotes I found funny or interesting.

Interview: Tutto Mountain Bike, Italy - Part II

Here's the second installment--of a few--from an interview I did with an Italian mountain bike magazine a few years ago.  You can read the first part here.  Since it was never published in English, and probably no one from the US saw it, I am posting a bit of it here; I'll post more of it later.  

Keep in mind that I was trying to communicate in language designed for non-English speakers.

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"What does it mean today be one of the most important American frame designers? Most of all a designer like you, who still believe in light cross country frames.”

Thanks for considering Seven to be one.

By ‘light cross country frame’ I assume you mean ‘hardtail’?  If so, we believe in the properly designed titanium hardtail.  A titanium—and to some extent, steel—hardtail can provide impressive ride characteristics.

The way in which Seven designs hard tails provides a unique ride.  There are four unique elements to Seven’s hardtail:

Interview: Tutto Mountain Bike, Italy

Here's an excerpt from an interview I did with an Italian mountain bike magazine a few years ago.  Since it was never published in English, and probably no one from the US saw it, I am posting a bit of it here; I'll post more of it later.  

Keep in mind that I was trying to communicate in language designed for non-English speakers.  Of which, I can relate--I often feel like a non-English speaker.

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“Once titanium was considered the most valuable material, today aluminium [and carbon] is chosen also for the most expensive bikes.  But the peculiarities of titanium are unique.  Why has it loosen its appeal?”

There is a long list of reasons that titanium is an excellent material out of which to build bikes.  A partial list includes:

·         Frame’s strength-to-weight ratio:  titanium alloys have the highest ratio of any bike frame material.  This include carbon fiber, too.  (I can explain why, if you are interested.)

·         Tunability of the ride characteristics:  titanium allows for a wide range of tube options.  (If the builder is willing to invest significantly in materials; see below for details)

·         Durability or fatigue life:  3-2.5 has the highest fatigue life of any frame material.  This means 3-2.5 builds the toughest frames.  This is particularly valuable for hardtails and dual suspension frames.

·         Durability in real world use.  Because titanium is so tough, it holds up better than other materials in daily riding conditions.  Steel and aluminum must be painted.  Aluminum is very soft so it dents—and therefore fails—easily.  Carbon fiber is has poor impact resistance so it is easily damaged.

·         Corrosion resistance:  steel rusts, aluminum corrodes.  Carbon is susceptible to UV degradation.

·         Customization:  Titanium—when used correctly—offers the most design flexibility of all frame materials.  Carbon must be molded.  Aluminum and steel offer tube sets in only a few options—by brand.

·         Overall Value per Euro:  because of all these factors, I believe that 3-2.5 titanium alloy—when applied properly—offers the best value per Euro invested.