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Do You Need a Triathlon Bike?

By Mikael Hanson (and first appeared in Curated's Expert Journal)

The quick answer is a resounding NO! In fact, you can complete a triathlon on any type of bike you’d like—triathlon bike, road bike, mountain, gravel, and in one case, my friend rode the New York City triathlon on a Citibike (part of NYC’s bike-share fleet) on a dare! If it has two wheels, you can use it for a triathlon! I’ve seen just about every type of bike used to compete in this swim, bike, and run event. Just What Is a Triathlon Bike? A triathlon bike, or time trial bike, is a bicycle designed specifically to “cheat” the wind through greater aerodynamics. Triathletes use these during the bike leg of a triathlon where drafting is usually not allowed (drafting is where a rider will slot in behind another rider and ride in their slipstream, which can save 25-30% of the effort one would use riding solo). Thus it is just up to the rider to move as fast as he can; the same applies for a bike racer in a time trial—a solo race against the clock. The triathlon bike has many features that differ from a standard road bike, each with the aim of making the bike and its rider more aerodynamic. How Triathlon Bikes Differ From Road Bikes

Author on his Tri bike in the Philadelphia Triathlon

A triathlon bike will differ from a road bike in many ways. For this reason, one should first learn proper riding techniques on a road bike before transitioning to a triathlon bike. Key differences include:

  • A triathlon bike has more aerodynamic tubes to help it slip through the air quickly.

  • Triathlon bikes have aero bars up front versus dropped-style bars found on road bikes (this does have drawbacks—especially where braking reaction is concerned).

  • The seat tube found on a triathlon bike will have a steeper angle to allow you to ride in a more-forward riding position to aid in holding the aerodynamic position (think downhill skier).

  • Triathlon bikes are generally paired with deeper aero section wheels.

  • Triathlon bikes tend to be heavier than comparable road bikes (bigger, flatter aero tubes will weigh more!).

How Does a Triathlon Bike Differ From a Time Trial Bike? You often hear the names time trial and triathlon being used to describe different kinds of bikes. Essentially, they are both used to cheat the wind, but there are subtle differences: A time trial bike is used by racers in individual time trials. These include races like the Tour de France. Each time trial has its own set of rules in terms of design and set-up—whereas triathlon bikes have no such rules. Some of these rules for time trial bikes include: having a “diamond-style” frame (also found in a common road bike), limitations on the width of aero tubes or bars (a 3-to-1 ratio), not allowing the addition of elements that are not “structural in nature” (i.e. aero fairings), and limitations on how far forward a rider can be positioned on their bike. These rules are set forth by the Union Cycliste Internationale (UCI), world cycling’s governing body, and have changed much over the past few decades.

Figure 1 (left): Cervelo P-series triathlon/TT bicycle. Figure 2 (right): Miguel Indurain on a 90s Pinarello time trial bike

Figure two shows former Tour De France winner Miguel Indurain on a highly specialized time trial bike in the late 1990s. These bikes were later deemed illegal by the UCI, as they sought to standardize how time trial bikes looked. Figure one shows one of the most widely used triathlon bikes, the Cervelo P-series time trial/triathlon bike. This bike satisfies all UCI rules and thus can be ridden in professional bike-racing time trials such as the Tour de France. Drawbacks to a Triathlon Bike

Figure 3: The Diamondback Andean Triathlon bike is not UCI legal and weighs in close to 21lbs—heavy by today’s bike standards and several pounds heavier than the Cervelo in Figure 1. A comparable, high-end road bike weighs less than 16 or 17 lbs.

While a triathlon bike may be an easy choice for someone looking to begin racing triathlons, they are not without their own list of drawbacks.

  • Weight: Triathlon or TT bikes can be heavier than a comparable road bike. They’re therefore not as easy to climb hills with.

  • Seat Angle: A steeper seat angle means the rider’s center of gravity is more forward, which will allow them to hold the forward aero-position with great ease. But, this will also make cornering at high speeds more difficult.

  • Braking Response: If you are riding in your aerobars, your hands are away from the brake levers, which are located out wider on the base bar. So accessing the brakes quickly is hampered.

  • Group rides: Triathlon/TT bikes are often not allowed in many group-ride settings due to the aforementioned braking/reaction lag.

Upgrades to Shave Time Without Buying a Triathlon Bike

So you want to see about going faster on your road bike before making the jump to buying a triathlon bike. There are many places you can look to improve your performance if you’re willing to spend a few bucks!

The Rudy Project Wing Aero Helmet

  • Body Position: Try riding in a more aerodynamic position first—like in the drops—as your own drag accounts for a large portion of the energy expelled to power your bike.

  • Aerobars: Add clip-on aerobars to put you into a more aerodynamic position.

  • Wheels: Add deep sections aero wheels.

  • Clothing: Wear more aerodynamic clothing like a triathlon suit.

  • Helmet: An aero time trial helmet can reduce your drag significantly.

Outside of a lighter, better-handling frame to help you cheat off father time, aerodynamics is another place one can invest money and be rewarded. For the time trialist or triathlete, reducing one’s drag coefficient (consider this your footprint in the wind) is of the utmost importance. Most studies on aerodynamics for the cyclist indicate wind resistance is the greatest force riders must overcome (Grappe et al., 1997; Kyle and Burke, 1984). These same studies show the body is responsible for the majority of this wind resistance (close to 70 percent), with the bicycle making up the rest (30 percent). Aerodynamic wheels can reduce the drag of the bike by 49g of force (Greenwell et al., 1995), or according to studies done by aero-guru John Cobb, a full two-to-three minutes of improvement over a standard set of box, 32-spoke wheels over a 40km distance. However, a set of top-shelf carbon aero wheels can set you back easily $3000 or more (for wheels from Zipp, HED or Mavic). A company called Lightweight makes a set that can run upwards of $5000 a pair! But no need to spend that much as cheaper sets can be found for under $1500. An aero helmet can also deliver a much-welcome aerodynamic advantage (without the huge hit to your wallet)—but only if worn properly: that is with tail down and flat against your back, versus dropping your head and having that long aerodynamic tail stick out like a shark’s fin in the wind (and why we are seeing the rise of the short tail aero helmets!). The early aerodynamic helmets were nothing more than a cheap plastic aero fairing added to a chinstrap—with no real protection. When the cycling world moved from no helmets (use among Professionals was voluntary in the 1990s and became mandatory in 2003) or allowing the minimally protective leather helmet (a.k.a. the ‘hairnet,’ as all it really did was keep one’s hair in place), aero helmets had to evolve as well. While a Tour de France rider competing in a 5km prolog or even a 45km time trial does not really need to worry about helmet ventilation, someone doing a half or full Ironman does. Rudy Project introduced the “Wingspan’ aero helmet in 2010. With the help of aero guru John Cobb, they produced not only one of the most aerodynamic helmets on the market, but also made a product that spoke to both the competitive cyclist and long-course triathlete by including vents that could be removed. They improved upon this model with their The Wing helmet (figure four) . Below is a look at other improvements one can make on their bike to help ’cheat’ the wind, which was put together by the Southern California Time Trial Series. Time savings are based on a 40km distance, or the standard length of an Olympic-distance bicycle leg, with a rider traveling at approximately 30mph (ya, like most of us can do that). These time advantages can be considerably less if riding under 20mph—something to consider before investing money into aerodynamic upgrades.

Handlebar Aerodynamic Savings From Drop Handlebar To Integrated aerobars Savings 2-4 minutes

Info from J Cobb, Vision Tech


From Shorts & Jersey To Skin Suit Savings 29 seconds- info from Rainer Pivit


From "Box Style" 32-spoke Wheels To Deep Front/Disc Rear Savings 2-3 minutes info from J. Cobb


From Round Tubing To Airfoil Chainstays, Down/Seat Tube & Post Savings 30 seconds - 2min info from J. Cobb, Martin/Cervelo


From Standard Road Helmet To L.G. Prologue TT helmet Savings 30 seconds info from J. Cobb - this data pre-dates Wingspan figure study

My advice to any new triathlete is to start with a road bike and first learn the proper skills like bike handling, cornering, braking, shifting, etc. Complete a few triathlons on your road bike, and if you are hooked, then consider getting a second bike that is a triathlon bike.


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