How to Choose a Triathlon Bike: Buying Dos and Don'ts

Rider on a Cervélo P3x triathlon bike. Photo courtesy of Cervélo. 

What Is a Triathlon Bike?

Triathlon bikes (also called tri bikes) are made specifically for triathlon racing where the bike leg can be anywhere from 12 miles to 112 miles. Tri bikes often have a steeper seat tube angle, pushing the hips forward on the ride and saving the hamstrings for the run. With the seat tube closer to vertical, the rider's hips are over the crankset, which engages the quadriceps for power. Tri bikes are aimed to make the rider aerodynamic, but also comfortable enough that they can perform well on the run.

Does a Triathlon Bike Make a Difference?

Rider on a Cervélo P5. Photo courtesy of Cervélo.

Triathlon is admittedly an expensive sport, because really, it’s three sports. And it requires a lot of gear. If you’re new to triathlon, you’re probably wondering, do I really need a whole new bike? You can certainly compete in a triathlon with a road bike, and actually, that’s recommended for your first race or two. There’s nothing worse than buying all the things and then realizing it’s really not for you. But after you’ve fallen in love with triathlon, you’ll want to know how much difference a tri bike makes. Tri bikes are made specifically with aerodynamics and geometry in mind. The goal is to maximize efficiency and preserve your legs for the run. After riding exclusively a road bike, your first ride on a triathlon bike will feel noticeably different. In time, you’ll feel much stronger on the bike and the run, all because of the geometry of the bike. Also, the frame design on tri bikes allows for nutrition and hydration to be stored in the bike, for quick and easy access.

What Should I Do When Buying a Triathlon Bike?

DO: Take a Test Ride

DON’T: Buy The First Bike You Try

DO: Research Bike Types

DON’T: Settle for What’s In Stock

DO: Talk to the Staff

DON’T: Skimp on Accessories

DO: Get the Bike Fitted to You

What Should I Consider When Buying a Triathlon Bike?

Andy Pruitt of Retül fitting a rider in the aerobars. Photo courtesy of Retül.

Above all, it’s important for your tri bike to fit correctly — not all 56cm frames are alike, and it’s important to tailor the bike to your body’s dimensions for comfort and efficiency. Have a professional bike fitter take your measurements, and test your flexibility and strength to get your new bike dialed in.

Comfort

When it comes down to it, any bike purchase should be about comfort. While an all-out time trial position might not seem comfortable, a tri bike should fit the geometry of your body. Every bike has adjustability, but some bikes can be much more complicated than others, even for small adjustments. Especially if you’re new to triathlon, your needs will likely change as you progress. Before buying, be sure to ask a mechanic about how difficult adjustments will be and whether your bike will have enough adjustability to accommodate your progression.

Price

Ask yourself what’s important and what’s not. Like all bikes, there’s a huge price range. Do you want Di2 shifting? Is carbon fiber important to you? Disc brakes or rim brakes? What kind of wheelset can you afford? Going in with a list of priorities, and a general price range, will help narrow down your search for the right bike.

Level of Commitment

And maybe your ideal price range has a lot to do with your commitment. Not everyone jumps into triathlon ready to take on an Ironman. If you’re planning lots of races and tons of time on your bike, maybe you should pay a little more for all the bells and whistles. But if not, there are plenty of tri bikes out there with more reasonable price tags. When purchasing your first tri bike, buying used is a great option!

Knowledge and Experience

The best way to really learn about tri bikes is to ride them. Just like any bike, you can read up on specs as much as you want, but until you feel what it’s like for yourself, you might not get a clear idea of what you like. Even if you find a bike you like right away, it’s always a good idea to ride a few more to be sure.

What Materials Are Triathlon Bikes Made Of?

The materials usually dictate the price of a bike, but less expensive materials don’t necessarily make a significant difference on the road. There are plenty of great tri bikes made with aluminum that will perform great.

Aluminum vs. carbon

This Cervélo P2 and BMC Timemachine TT02 are affordable aluminum traithlon bikes. 

Frame materials make a difference in how much a bike weighs, its aerodynamic shaping, and how it feels to ride. If you can’t afford a carbon fiber frame, there are plenty of aluminum bikes that are nearly as light and are excellent for beginner triathletes. A great way to upgrade an aluminum frame is with a carbon wheelset.

The Cervélo P3x and Felt IA Advanced show the aerodynamic frame shapes that are possible with carbon construction. 

Though, it’s no accident that the professional triathletes ride carbon. If it’s in your budget, carbon fiber lends itself to performance, and you’ll have more options when it comes to frame design. Carbon out performs other materials because it’s extremely lightweight, it’s easier to shape and thus is more aerodynamic, and it has a more forgiving feel. Carbon absorbs the bumps in the road, and keeps you from feeling the exhaustion that comes from them. That’s why so many forks, even on aluminum frames, are made of carbon. Same goes for wheels. When it comes to performance, feel, and aerodynamics, carbon truly shines.

Components

Components are what really make your bike work — all the small parts that allow you to shift and pedal. Luckily, components are fairly easy to upgrade, so if you start with mid-level — like Shimano 105 — you can always replace them with better parts — like Shimano Ultegra — down the road. If you want top of the line, check out Shimano's Dura-Ace groupset, or SRAM’s eTap AXS, and know: once you adopt electronic, wireless shifting, you’ll never want to go back!

What Should I Look for in a Triathlon Bike?

Frame Geometry

One of the biggest differences between a tri frame compared to a road bike is the handlebar configuration. Aero bars allow a rider to stretch their arms out and get as low to the bike as possible, to reduce wind resistance. It’s the same idea as being in the drop bars on a road bike, but with even better results. The seat tube angle is another noticeable difference between a road bike and a tri bike. A typical road bike has an angle of about 72-degrees, but on a tri bike it should be more than 76-degrees. You’ll also need to take into consideration seat tube length, top tube length, and head tube length. Once you know the ideal sizing on all of these, it will make your bike decision easier to narrow down.

Aerodynamics

Rider on a Specialized Shiv being tested in the wind tunnel. Photo courtesy of Specialized.

Tri bikes are built with aerodynamics in mind — from the cockpit to the built-in storage, brands are making their bikes to slice through the wind. But the absolute most aero bikes do everything to make the bike and the rider shaped in such a way that reduces as much drag as possible. Compared to a road bike, all of the tubing on a tri bike is shaped to glide through the wind. All of the edges of the bike are meant to reduce even the tiniest bit of drag, which in the end saves watts. Most tri bikes also have deep carbon rims, but more on that in a moment.

Wheel Size

Aero wheelsets allow for maximum efficiency to get the most speed from a rider’s watts. Wheels can vary quite a bit, but the biggest factor is the rim depth. Generally, the deeper the rim, the more aero, and the better the wheels slice through the wind. Unless, of course, there’s a crosswind. Then the deeper rims can act as sails and push the wheel, making bike-handling quite challenging. For this reason, many pros have a variety of wheelsets to choose from, depending on the race they’re riding. Examples of aerodynamic wheelsets: Shimano Dura-Ace C60 Clincher Specialized Roval CLX 64 Bontrager Aeolus XXX 6 TLR Disc

Storage

Cervélo P-Series with integrated top tube storage. Photo courtesy of Cervélo.

This is especially important for longer triathlon races, such as 70.3 or full Ironman distances. Onboard storage for hydration and nutrition (and even some tools) is important because the bike leg of a triathlon is the best opportunity for athletes to really focus on consuming fluids and calories. Some bikes come with storage built in, and others, like Quintana Roo, sell add-on compartments, like their top tube storage box, or their QBOX rear storage.

Gearing

Are you riding in Indianapolis, or in Boulder? Your gearing will depend largely on the terrain you’re tackling. You’ve generally got three choices when it comes to chainrings: standard 53/39, semi-compact 52/36, and compact 50/34. Either 10 or 11-speed cassettes give a huge range. Plus, changing a cassette is fairly easy, so it’s something you can play around with.

Conclusion

There’s a lot to consider when purchasing a triathlon bike. Above all, take your time. Get a proper fit. Test several bikes. Think about wheel sets, components, and accessories. If you’re buying a bike specifically aimed at improving your triathlon race, you don’t want anything to feel off. After all, a tri bike is not only helping your ride, it’s also helping your run.