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.  

That initial project happened when I was working at Merlin Metalworks.  We were doing a project for John Tomac who was racing for Mongoose bicycles at that time.  Tomac had already been racing on Mongoose branded Merlin titanium frames for a while.

Digression

Not to digress too far, but John Tomac was only my second bike idol.  I was fortunate to see him race a few times and his ability on a mountain bike is still something I’ve not seen matched.  For those that don’t remember Tomac, from the mid-eighties through the early nineties, he was winning both cross-country and downhill races on any given weekend.  He came from a BMX racing background, and his bike handling skills were something to behold.  And, oh yeah, by 1990 he was also a professional road racer—in Europe—and winning some big races, there, too.  There was even a time when he was racing his mountain bike with drop bars—and kicking everyone’s rear end.  I started racing with drop bars, too—because of him—but I didn’t get anything but my own but kicked.  Back to the story…

Can’t Leave Well Enough Alone

So, there Tomac was, racing a full titanium Mongoose that we—Merlin—had built.  He did really well on it and seemed to like the bike.  At that same time, Gwyn Jones—Merlin’s President—had a friend that worked with carbon fiber in the boat industry.  They decided to see what Merlin could do to bring together, in one frame, titanium and carbon fiber. 

Due, in part, to our really good success with titanium frame design, we had some serious concerns about the idea of applying carbon to mountain bike frames.  For example, at about the same time that we were testing some carbon ideas, Bicycle Guide Magazine wrote a very unfortunate review of Kestrel’s brand new full carbon mountain bike frame.  Since this review is 20-years old, I think it’s okay to recall that the frame broke on the first ride of the test—and the tester wrote about it in the magazine.  Of course, this was an exceptional defect, but the message was clear—carbon was not quite ready for the demands of all out mountain bike riding.

The More Things Change, the More They Stay the Same

It's interesting, to me, that two of the primary challenges for carbon, that we saw 20-years ago, are still some of the primary challenges carbon faces today:  durability and impact resistance—particularly for mountain bikes.  The only difference appears to be that these days no one seems to care about carbon durability.  I digress—back to Tomac.

Leverage Strengths; Mitigate Weaknesses

Since we knew that Tomac would destroy any existing carbon tubing, we looked for a more clever solution.  Gwyn and his expert friend decided to design carbon “tubes” that were torsionally stiff—exactly what Tomac wanted in the frontend of the frame.  That was relatively easy.  The trick was, of course, making carbon fiber durable enough to withstand a season of Tomac’s brutal racing.  Fortunately, that’s where titanium shines:  toughness and durability.  We had found a good match of materials; in essence, we employed the titanium as a protective shell around the carbon fiber top tube and down tube.

Tricky

It was easy to come up with the titanium wrapped carbon concept.  The trick was figuring out how to make it work.  We couldn’t put the carbon in the tubes prior to welding; the heat from welding would delaminate the resin and epoxy, and nullify the desired effect of the carbon composite.  So, we had to find a way to get the carbon into the tubes after the frame was welded.  And then inflate the bladders, bake the frames, bond the carbon to the titanium, and finally, extract the bladders.  That was fun times all around.  But it worked.  And Tomac got results. 

Cutting Edge

This was a long time ago.  In the late eighties, all carbon frame builders were just getting started—at least, the carbon frame manufacturers that are still around today.  For example, Kestrel introduced the world’s first monocoque frame in 1986.  Look Cycles had just started offering lugged carbon frames at about the same time.  So, there were only a few companies working with carbon.  And the only carbon mountain bike that I can recall was the ill-fated Kestrel mentioned above.  So, we—Merlin—were right at the front edge of carbon testing—particularly in the mountain bike realm.  I'm not aware that anyone else in the bike industry had ever used carbon fiber—or titanium—in this way before.

Unfortunately, the frame wasn’t particularly sexy to see; it looked like a titanium frame.  You couldn’t see the carbon fiber since it was hidden inside the tubes.  In fact, it was so innocuous that only a handful of people ever even knew that there was carbon inside some of the titanium frames that John was racing back then. 

Dates Are Hazy; Results Are Not

I learned a lot about carbon during that project.  Some of the techniques we tested for Tomac still serve me today.  Twenty years later, everything that’s new is old.

And speaking of twenty years ago, that first carbon project was just the beginning of a two decade journey in carbon fiber research, development, and frame production.  Do you know what the next couple carbon projects were?  Stay tuned.

Comments

[Yoshi]

The picture is so cool. I have'nt had any experience about making carbon frame so far. It is said the strength of carbon frames is still unknown quantity, but the development has been kept and improved. What if in the future we are able to have complete carbon bike, or superseded the other material?

[mike]

Rob,
do you have any information or memories regarding the 6 ti/carbon raleighs tomac used in 1991 & 1992?
many thanks!
mike