Road Bike vs Tri Bike
This past Monday I had a Retul bike fit from the guys/gals at Colorado Multi-Sport in Boulder. Retul is a software that, combined with cameras and sensors, can analyze all aspects of your cycling. My request was to get into a “tri configuration” on my road bike; which included purchasing bold-on aero bars. Firstly, the guys were great and were very helpful, if you need a bike fit and are in the Colorado area I would recommend giving them a call. Secondly, the obvious question arose, why not just get a tri bike? We will get to that, but first, lets look at the fit.
Since I have been riding road bikes for a few years I can tell by feel how a road bike should fit. When I went in, my road configuration was essentially spot on. The easiest way to explain the difference in configuration is to have pictures. This is me in a standard road configuration.
When riding on the top of the handlebar I have a fairly upright position. The Domane is an easy bike to fit. The reason I sit so high is that the top tube, the upper tube that connects the seat tube to the handlebars is fairly short. In road configurations you get into a more aerodynamic position by dropping the handlebars or extending the top tube a little bit to lower the upper body. In my case I ride on the “drops” to lower my body. Before you feel bad that I ride so upright, I can go pretty fast in this configuration without issue.
One of the things that people talk about all the time as a major difference between road and tri bikes is the seat tube angle.
This is a road seat tube position. Standard 74 degrees, no surprises. When they talk about the seat tube angle, what they are really saying is that they want to get you closer to the handlebars. In order to do that, you can change this angle and when you are seated, your body will be closer to the front of the bike.
When you bolt on aero bars and get ready to go, you are probably too far away from the front of the bike, you can see my elbow is not 90 degrees, I am low but I am reaching to get to the bars. You can’t see this but I am also way too far forward on my saddle, which is incredibly uncomfortable.
There was a solution for me, and it was very simple. First, lets look at the change.
Now I am closer to the bars and, as you can see, my elbows are closer to 90 degrees (not perfectly) which is more comfortable. I am also not riding on the front of the saddle. So what changed?
We turned the seat post around. As you can see, the seat tube that comes on the Domane is set at an angle. Turning it around changes the angle from aft to fore, effectively changing the seat tube angle without much work. Just that change was enough to shove me forward. I also have some room on my saddle rails, if I have to move slightly forward I can make that adjustment with a hex wrench.
You can see the difference in the handlebar reach measurement.
Normally the top of the saddle to the handlebar is 503 mm. Making that change adjusted that –
If I need to close the reach a little more, I could move the saddle forward on the rails. This still isn’t a perfect tri fit – but better than I was. Specifically, my handlebars are a little bit too high. The Domane comes with spacers on the stem which can be removed in order to lower the handlebars. This is something I know a few people do because they like the Domane’s comfort and handling but want something a little more aggressive for racing. I am also still operating my brakes and shifters on the regular handlebars, I could get bar end shifters for the aero bars but that would be a pain to set up and tear down when I want to change configurations.
We went through a little science getting into this position, why wouldn’t I have just purchased a bike like that in the first place. The answer is simple, road bikes have been produced with slack seat tube angles for years because it is a very efficient position for power output. Riding in my road configuration is easy on my back and my knees. I can go up hills, stand on my crank, ride on the drops downhill, without issue. In this position if you stand up you might hit your knees on the handlebar!
I am not the only person to want it both ways. In fact, Specialized is producing a bike which does exactly what I have done to mine. The Specialized Alias is essentially a modified road frame with a seat post that can be switched out, and standard clip-on aero bars.
Like the Domane, the top tube is not very long. Unlike the Domane, the seat tube angle is steeper. You can look closely and notice the seat post does not have an offset angle of its own, like mine does. The handlebars don’t seem to be spaced on the head tube like mine are, although for some riders they might need it to be added.
Ultimately my goal was to ride in a comfortable aero position. You can ride on the drops and get out of the wind, but that can get uncomfortable and my hands have a tendency of going numb when I ride in the drops for a long time. With the clip-on bars, I can rest my upper body on my elbows which should be less fatiguing while getting me out of the wind.