Interview w/ Ted Tanouye - Headtube Sizes

Ted Tanouye is CHUMBA's head designer and founder.  The son of a NASA engineer with mulitple ground-breaking designs under his belt that have competed successfully in national and international races, Ted is one of the sport's true legends.

Interviewer: The rage these days seems to be on tapered headtubes, do you think they will become an industry standard?

Ted: I can't say for certain what will happen in the future; however, building frames for over 20 years, I have seen ovalization of head tubes at the lower cup area on race frames, and we have seen manufacturers react to this.  What they have done, including myself, is add headtube wall thickness and gussetting of the headtube junction areas.  For instance, on the F5, we do use a 1.5" outer diameter, as well as wrap most of the headtube with a reinforcing gusset.  The number of reported instances of stress risers and ovalization on recent DH frames is almost zero.

Interviewer: What about trailbikes?  What is your experience with ovalization?

Ted: Aluminum will always have a fatigue life.  And, depending on the type of usage these bikes expose themselves to, you could see massive amounts of force applied to the lower area of these bikes.  10 years ago, I woud never have imagined that trail bikes would be subjected to the type of abuse that they undergo today.  Also, it's not only the ordinary usage, but flat-landings and slip-ups during jumps and drops could mean that the head tube is subjected to forces that are far magnified compared to ordinary trail-riding or if you were to have a smooth transition or landing.  Taking all of this into consideration, manufacturers  seem to be trying to deal with this problem by increasing the head tube size by using a larger bearing to dissipate stress, and increased surface area for mitering; however, it's tough to say how effectively these proposed solutions will work out in the long-run.  However, we can say with some certainty that the lower head tube area will usually ovalize first over time wth repeated stress.

Interviewer: So what is the future of CHUMBA's headtubes?

Ted: Any time we propose a change in the frame, we deliberate over the change, and try to review as much data as possible to make sure that the change really affects performance and durability in the long run.  We really try to resist the urge to jump on the band-wagon, as there is a lot of pressure from industry hype to adopt new standards.  We will take a wait-and-see approach before committing to a change.

Interviewer: Thanks for the information, and hope to talk again soon.

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