A triathlon or time trial bike demands a fundamental change in body posture as compared to other styles of bikes. With the increase in aerodynamics comes a decrease in comfortability. This is easy to understand once we examine the geometry of the bikes themselves.
The geometry of modern triathlon bikes was first penned by Dan Empfield in the late 80s and came to market in 1989 as the first Quintana Roo bicycle, the Kilo. Mr. Empfield developed two fundamental geometry changes to tri bikes, both of which allow the rider to comfortable and powerfully ride a lower and more aerodynamic aerobar position.
First, the seat tube angle of tri bikes is steeper, or closer to perpendicular to the ground. This moves the saddle forward relative to the bottom bracket (or center of pedaling axis). Second, the head tube length of the bike is shorter which moves the aerobars lower. We can think of these two changes as rotating the entire geometry of the bike forward around the pedals.
This rotation of the bike’s geometry only works when the rider undergoes a similar rotation with the focal point of this rotation coming from the hips. This is called anterior pelvic rotation and is the most problematic aspect of beginner triathletes comfortably fitting on a triathlon bike. On a traditional bicycle the wide and padded part of the saddle contacts the riders sit bones. On a triathlon bike with the forward rotated fit the rider will come off the sit bones and onto the area of the anatomy called the perineum. The perineum is an area not well prepared for hours of pressure.
Or as I like to tell fit clients… “Bike saddles are bad, worse in aerobars, and worst of all for females in aerobars.” Don’t write off your chances of riding a triathlon bike just yet. Saddle advancements in recent years have greatly improved what was previously a less than ideal situation for men, and a downright ugly proposition for women.
Modern triathlon saddles come in many shapes sizes and designs. There are the long nosed and super padded saddles like the Profile Design TriStryke and the Fizik Arione tri. There are also non-traditional noseless ISMs and Cobb’s JOF55. There is almost always a shape that will allow any rider to achieve proper anterior pelvic rotation.
The Myth of Comfort
Expectations can be the source of our unhappiness and using the word “comfortable” to describe a bike seat is often setting an unreasonable expectation. Of course if your previous saddle caused bleeding welts and your current saddle solves this, certainly your current saddle is more comfortable in a relative sense. I prefer the term sustainable. If you need to ride 112 miles in the aerobars and your saddle allows you to do this, even if it feels like a flaming fencepost by the end of it, you are probably at least in the neighborhood of “as good as it is going to get”.
The right saddle for you should both feel instantly better as well as continue to improve over time. As we rotate forward into the triathlon position on the popular noseless saddles we are contacting the seat with the sides of our pubic bone. These bony structures will adapt to their weight bearing role far better than the soft tissue of your perineum ever will. Combine this ability to adapt with several other factors and eventually most riders can achieve the ability to ride in aerobars for many hours at a time.
As a beginner triathlete at a proper bike fit you should try several saddles before commencing with the “fit proper”. Choosing a saddle and learning the posture is step one. I let every beginning fit client know that today is as bad as it will ever be. During our fit we will get more weight onto the front of the bike and thereby less weight on the saddle. During your training you will get stronger, pushing more force into the pedals resulting in less weight on the saddle. Many beginning triathletes will shed some body weight resulting in less weight on the saddle. And finally, the body and mind will toughen to the task at hand. These factors will eventually come together into a “nexus of sustainability” and allow you to sustainably ride a proper triathlon bike.
To find your own nexus of sustainability schedule a fit with all3sports today. If you are not in the area feel free to give us a call to discuss your bike fit.