Wednesday, March 21, 2012

Tri Bike, Road Bike, or Road Bike + Clip-On Aero Bars?

Spring has sprung, and it's the beginning of another triathlon season.  As athletes make their competition plans for the year, one of the most common questions asked is if a tri bike or a road bike would be better for a given race course.

We know the pros and top age-groupers all ride tri bikes.  Shouldn't we all?

First, lets review the big, fat, primary advantage of a tri bike: It permits you to ride in a very aerodynamic position for long periods of time while creating maximum power with minimum discomfort compared to a road bike.  That's it.  There is no other reason to get a tri bike.  While there are secondary advantages, they are minor, trivial even, compared to the aerodynamics.

Let's look at what a tri bike is not:
  1. A tri bike is not more comfortable on long rides than a road bike:  It is built for speed, not comfort.
  2. A tri bike is not as easy to turn as a road bike:  It is optimized to go very fast in a straight line.
  3. A tri bike may limit your descent speed compared to a road bike: The steering can be less stable at high speeds.
  4. A tri bike is a hassle on courses with frequent hills and lots of turns: Moving back and forth between the shifters and brakes, and between the aero bars and the handlebars, can quickly get annoying and can lead to mistakes.
It is also important to realize that a tri bike has disadvantages that affect amateur athletes to varying degrees:
  1. A Tri bike should be your second bike.  If you ride on roads with traffic, a tri bike can be significantly less safe than a road bike primarily due to the location of the controls (brakes and shifters aren't integrated) and the riding position (more difficult to ride upright to observe traffic and to be seen).
  2. It can be difficult to get enough practice time on a tri bike.  Since it is not a good idea for most folks to ride a tri bike on the road, especially in groups, the best tri bike riding is often done on a closed or limited-access course, such as Fiesta Island.  Which for most of us means loading the tri bike on the car and burning expensive gas in order to get a ride in.
  3. It can take many hours in the saddle to adapt to a tri bike fit.  Maximizing performance, posture and muscle development can require lots of contact time: If you can't invest the training time, a tri bike could yield little or no improvement for a significant cost.
So, let's say you have a race coming up with a fast and flat course that screams "Hammer Time!".  Should you get the tri bike, or not?

My personal opinion is that there are lots of better ways for us non-podium folks to spend money than on a tri bike.  Perhaps spend the money on travel to a distant race.  Or get a power meter, a GPS training watch, and some rollers.

But if money is no option, then by all means get a tri bike!  Just don't expect any magic from it: It takes work and commitment to obtain the benefits a tri bike offers.

What if you could get 80% of the benefits of a tri bike for 5% of the cost?

Remember, the primary advantage of a tri bike is all about aerodynamics.  How can you improve your aerodynamics on a road bike?  There are two basic ways:
  1. Get comfortable spending time in the drops.  I've never been able to do this: To me, the drops are for descents and stiff headwinds, and little else.  Unless you happen to like numb hands and aching shoulders.
  2. Get some clip-on aero bars for your road bike.
Clip-on aero bars do have some functional disadvantages compared to a tri bike:
  1. It is awkward to shift while in aero, since there are no shifters on clip-on aero bars.
  2. It can be awkward to move to and from the aero bars, due to the geometry and placement of typical road bars.
  3. The aero position using clip-on aero bars is often not as aggressive as what you can achieve on a tri bike.
Fortunately, all the above can be minimized (though not eliminated) by lots of training, careful clip-on aero bar selection, and proper fit adjustments.

However, there is one more very important negative issue with clip-on aero bars:  Weight distribution.

Your center of mass shifts forward on a road bike when in the aero position, much more than it does when riding in the drops.  This shift can greatly increase the amount of your weight on the front wheel, which in turn can dramatically affect handling.  One of the key design features of tri bikes is to bring the rear wheel as close under the rider as possible, specifically to address the weight shift issue.

If you choose to try clip-on aero bars, be prepared to also do the following:
  1. Get a tri bike fit in order to learn your optimum aero geometry.
  2. Select clip-on aero bars that, combined with handlebar height and stem adjustments, will bring you closest to your ideal aero position without negative effects.
I've seen folks who did everything possible to equip a road frame with tri bike components. This is not recommended!

First, it can ruin the usefulness of your bike when riding on the roads, when riding it as a road bike.  You should ensure any adjustments you make do not significantly affect the handling or comfort of your road bike.

Second, road frames tend to make lousy tri bikes.  That's why the tri bike frame was invented in the first place!

When I first got into triathlon a few years ago, I already had a good fit on my Trek Madone 5.2 road bike, and I bought a tri fit from JT at Moment for two reasons: First, to learn what a good tri fit felt like, and second, it was my initial step toward deciding if I wanted to budget for a tri bike.  I was surprised at how different the two fits were, and how differently my body performed in each position.

While I really liked being in aero, my back didn't handle hammering in aero very well.  So I figured I should wait on getting a pure tri bike, and got my clip-on aero bars as a first step.  When my back completely failed a couple years ago, I had to get a TitanFlex to isolate my back from road shock and vibration, the alternative being to give up biking, and triathlon.

Over the past year I've been experimenting with tweaks to my bike fit on my infinitely adjustable TitanFlex AlTi.  The only thing not adjustable on this bike is the wheelbase and the angle of the steering tube.  The titanium support beam permits the seat to move forward and back over 4 inches with a similar vertical adjustment on my seat tube, and I have an adjustable stem that permits my handlebars to be moved almost anywhere, along with adjustable clip-on aero bars and elbow pads.

As I evolved my bike fit in the space between my road and tri fit values, I developed what I call my "troad" (tri-road) fit, where I've adjusted my seat post angle to be right between that of a tri and road bike, which is the furthest forward I could move my body on the TitanFlex frame without affecting handling.  I also found I couldn't get quite as flat in aero as JT's fit permitted, though I did get surprisingly close.

I think I've found a sweet spot that gives me the best aero ride a road bike can offer.  We'll see if it's true as I build volume into the Spring.

If you want to buy another bike, I would suggest taking a ride on a TitanFlex with clip-on aero bars, in addition to any tri bikes you try.  Experiment with finding your "troad" fit.  Instead of buying a second bike, you may be able to switch to a single bike that will give you the best of both worlds.

Be sure to also try clip-on aero bars on your current road bike: Combined with a new fit and some careful adjustments, you may find your own sweet spot.


  1. And if you do go clip-on, you may want to read and

    1. This comment has been removed by the author.

    2. I wrote a reply to this comment, but it became so long I decided to make it the next post.

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