Going Going Bike

Jan 262011
 
Triathlon Bike

Turning up at my first sprint triathlon it was difficult to hide the fact that my road bike was not the same as most of the other bicycles being wheeled down to transition. Mine was a standard road bike with drop handlebars. The vast majority of other bikes were tri-bikes with aero handlebars and a dramatically different geometry.

Do I need to buy a tri-bike?

After the event I set out to discover whether I needed to buy a triathlon bike or whether I could adapt my road bike for the triathlons I had scheduled into my race calendar. I discovered that it all came down to aerodynamics.

The vast majority of the work you do on the bike in a triathlon, once you’ve got up to speed, is to work against the resistance created by your own body moving through the air at 35km/h (or whatever your speed is). This is a bigger factor in triathlon than road cycling because of the restriction on drafting in Triathlon.

As a result of this aero is king and getting your body in an aero position is the most important bit of aero. This is far more important than fancy wheels, leg shaving, speed suits or pointy helmets (but they do help a bit too).

Aerodynamic

For my next triathlon, In order to create a better aero position, I attached some aero bars (borrowed) to my road bike and, once I got used to the different handling, I began to enjoy the more “aggressive” aero position (originally modelled on a downhill skier). In addition I found my heart rate remaining lower for an equivalent speed.

A bit of extra advice from some more experienced friends resulted in my saddle moving forward, dropping the handlebars down as far as they go and making the stem a bit longer so as to achieve  a decent aero position – lower, smaller frontal area, flatter back.

The problem with this set-up was that the bike was pretty hard to ride. My weight was much too far forward and the back wheel started to unweight and slide on fast corners. My dropped handlebars (remember this “was” a road bike) were too low to be useful and reaching the gear levers was near on impossible.

Bicycle Geometry

A good tri bike is designed to be ridden in this position without any further alterations. Have a look at the triathlon bike in the photo above. The seat post is steeper to put the saddle further forward to begin with. The back wheel is tucked right under the saddle, made possible by a cut-out seat tube and very short chainstays. This means the weight distribution remains more even when you lean forward. The handlebars are cow horns, not dropped and the gear levers are at the end of the aero bars, right where your hands are.

All the other things on a good tri frame, weight, stiffness, teardrop shaped tubes, internally routed cables, hidden brake calipers are nice-to-have which may shave seconds off your bike splits. Being able to ride fast with your body in an aero position will save minutes.

So, do I need to buy a tri-bike for this season’s triathlons or can I continue to ride my “upgraded” road bike? The answer is no. The biggest changes to my performance will be earned out training rather than investing in expensive kit. Do I want to buy a triathlon bike? Well that’s a different question and the answer is clearly yes!

You may also be interested in:

Fuelling your endurance races: Part 1

Fuelling your endurance races: Part 2

  3 Responses to “Do I need to buy a tri-bike or can I adapt my road bike for triathlons”

  1. [...] bike or adapted road bike (check out our blog on “Do I need to buy a tri-bike?”) are best. Whatever you ride you will be hampering your performance unless it is in good [...]

  2. Hi

    I brought a Cube cyclo-cross, so good for commute, canals, tracks and have got some 32 tyres for Winter. Will switch to gator skins, 25 for the Summer commute and with these tyres will be good enough for any tri, whether sprint or ironman

    Mark

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