How to Choose Your Next Tri Bike: An Engineer’s Guide (Step 1)

Let’s say you’re a dedicated triathlete. You’re in your fourth or fifth year of participating in the sport and you’ve decided to commit to at least another five or six in pursuit of a long-term goal. Maybe you want to go to Kona or the Rev3 championships. Maybe you want to take a crack at Olympic Distance amateur nationals. Whatever the case, you’re ready to take things to the next level. You’re putting in the workouts, the recovery and the diet. It’s all coming together and you want to make the most of it, so you start to look at buying the best bike to maximize your potential.

FASTER triathlon bike transition area
Photo courtesy loop_oh

This quickly becomes a dilemma for 90% of athletes who consider “taking it to the next level.” Top-end bikes today can cost as much as some cars and the process of choosing a bike can feel much like car shopping, with all kinds of package deals and special incentives offered by different manufacturers and retailers. There are also the reams of data and marketing blitz that go into convincing you how superior one bike is over another. Much like car shopping, you can feel a little hopeless at the moment of the final decision, filled with doubt not only in the bike you’re choosing but also in yourself and the process by which you made your decision.

The key to not ending up like a worried car buyer is to never start out like a car shopper in the first place. After all, it’s not a car, it’s a bike! You don’t have to worry about engine temperatures and suspension spring constants. This is very simple stuff. You can make a judicious decision based on a holistic, scientific approach. Instead of thinking like a customer buying a car, think like an engineer building a bike. That really is what you’re doing.

Photo courtesy trib

It may seem like a bike or tri shop wants to sell you the specific sample bikes they’ve built up, but you don’t have to buy that specific build. No one is forcing you to buy x-bike with y-wheels and z-shifting.  Cars come with options, but a bike can be anything you want it to be. The fork, handlebars, wheels, brakes and transmission can all be taken off and replaced with different parts. You have a nearly limitless capability to make your bike everything you need it to be. Look at the whole bike and build it up step by step. The primary concern in choosing a bike is how it fits the athlete. Optimizing position for comfort and power generation will always be a triathlete’s top priority. But the seasoned athlete will also try to weigh aerodynamics as well. In fact, after an athlete eliminates the one or two bikes that simply won’t fit for whatever reason, aerodynamics will be one of the biggest discriminating factors in their choice.

And this is where things become even more frustrating, because making an accurate comparison seems nearly impossible. The preponderance of aerodynamic data on bikes is published  by the bike manufacturers themselves in what has come to be known as the standard “white paper.” Not surprisingly, which bike performs best in the wind tunnel depends on which company published the paper. It’s easy to become cynical and think all the numbers are rigged. That’s not necessarily the case, and though there is certainly quite a bit of creativity in how the data is presented, there is still value in taking a look at them.

Photo courtesy Justin Zatkoff

That look can’t be a simple glance. If you really want to comparison shop your bikes and gain confidence in your choice, you’re going to have to invest some homework before you spend your dollars. The real value in manufacturer white papers is what you can read between the lines. While the process is involved, we can break it down into steps that provide a clear set a metrics for comparison. They are:

1. Define your goals
2. Assess your own performance
3. Narrow the choices by price and fit
4. Find the manufacturers’ white papers
5. Look for independent research and reviews
6. Get a test ride and weight measurement
7. Compare aerodynamic data
8. Weigh the intangibles and make a final decision

Some of these steps are less fun than others, but not as complicated as you might think. At any rate, nothing is worse than buyer’s regret. Let’s go through each step in a little more detail. Today we’ll discuss the first two steps.

Define your goals

This is the first step in any technological endeavor. It doesn’t help to have the world’s fastest triathlon bike if you’re shooting for the national BMX championships. Decide what your ultimate goal is and what milestone races take place on the road to that final accomplishment. What do the bike courses look like? What rules are there about the bikes allowed to race? Most Olympic-distance triathletes ride road bikes with aerobars clipped on. Their position allows them to deal with the demands of pack riding, as well as tight turns and quick accelerations. With few climbs and no drafting allowed, long-course athletes go with time trial bikes.

Assess your own performance

This is a simple, two-part matter. How fast can you go and how uncomfortable do you get on the bike? To the first part, speed is a major part of aerodynamic considerations. As discussed in my new book FASTER, aerodynamics matter exponentially more the faster you ride. It is also normal, but not guaranteed, that a more aerodynamic position will also be less comfortable. You will generally get lower on the elbow pads, simultaneously increasing the amount of bend at your waist and neck. Even pro Ironman athletes gripe about the discomfort they can experience during a race. Much of that is due to the fact that they spend a significantly greater percentage of time in the aero position than average athletes. Even when they experience extreme discomfort, they will remain in the aero position instead of sacrificing valuable seconds in a less efficient one. Furthermore, some pro athletes assume gradually more aerodynamic positions from year to year as their body adjusts to riding that way. So even at the top level, it takes some people years to get in a position that is not only aerodynamically fast, but physically tolerable as well. The two go hand in hand.

There is a big lesson to understand in this. Regardless of how good the bike is, the rider always makes up about 70-75% of the total aerodynamic drag. If you can’t ride in a fairly aggressive position on your current bike, spending money on extreme aerodynamic improvements in your new bike will yield only marginal benefits. Depending on your goals, your money may be better spent  in the near term on yoga classes and deep tissue massages to help you achieve a better position.

If you’re interested in getting faster, you’ll be fascinated by FASTER: Demystifying the Science of Triathlon Speed. In Faster, astronautical engineer and triathlon journalist Jim Gourley explores the science of triathlon to see what truly makes you faster—and busts the myths and doublespeak that waste your money and slow down your racing. With this knowledge on your side, you can make simple changes that add up to free speed and faster racing.