I recently went through a bike fitting analysis (triathlon positioning) with a well known and respected organization. I was advised to go with a 78
degree seat tube angle, based upon all the measurements, hip flexion, etc. The sizing was done using a Serotta fit cycle. My choices in buying a new triathlon specific ride is somewhat limited due to the recommended
seat tube angle. The Cervelo P2C is the carbon frame of choice. I’ve
heard very good reports from other local triathletes, in favor of various other carbon frames, all with 76 degree seat tube angle. Will I sacrifice too much comfort or power output if I go against the advised 78 degree for a 76 degree set up???
Did they use a power meter?
No, they did not use a power meter.
This is probably a better question for your bike fitter than it is for a bunch of anonymous know-it-alls in the Internet netherworld. There is also an issue with a discenting opinon from some anonymous “expert” disagreeing with what your fitter says. That sets up a conflict for you: Who do you believe, the guy you *know *whom you just paid for a fit, or some fella on an internet forum who has no culpability or responsibility to be sure the information he/she is giving you is accurate?
That said, don;t forget that a big benefit of riding steep is the transition from bike to run. I wager your fitter is in touch with this reality. That may be a good sign.
The trend in geometry for the 2007 model year suggests that manufactuer’s foray into the 76 degree seat angle was neither a technical success or an overwhelming sales success. Customers are becoming more sophisticated now and are looking at the geometry charts and asking well informed questions like yours. As a result, they are finding out that a 76 degree seat angle does not suit everyone (no angle, including 78 for that matter, does) and that a mamby-pamby “safe” route of being half way between road geometry and tri geometry only makes for a mediocre road bike or a mediocre tri bike- take your pick.
You’ve got to realize that Slowtwitch is likely the center of the “ride steep” universe, so bear that in mind. Around here, I’d say 78 degrees is almost considered a standard setup, and as many ride 80+ degrees as 76 or less.
Your hip angle and saddle to bar drop will likely have more impact on your power and comfort than the nominal seat tube angle. You will have to train in the forward position for a few months to adapt to it if you’re used to riding a slack, roadie position.
Have you read the various fitting articles on the main Slowtwitch site?
If you want to ride steep then you should call Ves at Yaqui bicycles, but only if you are more concerned with form than the latest trendy bike. He can build something at 78 or steeper that will fit you perfectly and handle better than other bikes. It will likely be aluminum, but he paints them himself and his bikes are beautiful.
Chad
triguy1951,
Why would you pay? for or at least subject yourself to a bike fitting analysis (triathlon positioning) from a well know and respected organization and then depart from their recommendations for your most productive fit? Do you wish to sacrifice power and comfort? For what benefit? Don’t forget that when you optimize the engine you create the opportunity for the best performance.
The choice is yours.