3 Triathlon Bike Fit Mistakes That Are Slowing You Down

Making the most of your triathlon bike means fitting it properly to get the aero benefits while saving your energy for the run on race day.

Triathlon bikes are certainly faster than road bikes on a bike course adapted to suit them. That means, if you’re looking to go really fast on a relatively straight course without technical sections, the tri bike is the best choice. However, the correct fit, your increased comfort, and confidence combined with sufficient practice will give you the edge on race day.

How can you make sure your tri bike fits well and that you’ll get that nearly 20-minute speed gain on your IRONMAN triathlon ride? Avoid bike-fitting mistakes and prepare for race day by practicing with your bike and training appropriately.

In this article, you’ll learn:

• The difference between triathlon bikes and road bikes;
• How to fit your tri bike and your road bike to maximize comfort and speed;
• What benefits you can expect from each bike, and;
• How to choose the right tri bike shoes or road bike shoes.

Triathlon bike vs. road bike: What’s the difference?

When you’re preparing for your first triathlon, or even if you’re a tri veteran, you’ll be considering one of the big questions: which bike should you ride on race day? While triathlon bikes on paper are faster than road bikes, there are advantages to both, and you should look into how they can benefit you and understand their main differences.

In an experiment I did recently, I discovered that I could sustain 150 watts of power on a tri bike at about 2-km/h faster than on a road bike. However, that’s going fast at a steady speed, without turning around corners or having to stop and start or avoid obstacles. It’s also in a non-technical setting. The key difference between the bikes, then, is that a triathlon bike is faster than a road bike, all things being equal, on a straight, non-technical course.

Why is a tri bike faster than a road bike?

One of the reasons the triathlon bike is faster is its aerodynamic design. The geometry of a tri bike means improved aerodynamics for both the bike itself and the athlete. When you ride a tri bike, your body is positioned further forward with your weight above the handlebars, while the saddle and the pedals are all positioned such that your body takes a sharper, more aero shape.

Also, in terms of design, tri bikes don’t have to adhere to UCI rules around weight and frame. This means they can have unique geometry with new shapes and tubes. The convenient integrated storage for your bottles and nutrition saves on drag compared to having an extra saddlebag during a long-distance triathlon.

With a tri bike, the seat is a bit further forward; the front has a flat base bar with aero-bar extensions that keep your hands out at the front. You won’t have the same access to your brakes and shifters, and even the saddle has a different design, pointing downward on a tri bike.

The other big reason that a tri bike is beneficial for a triathlete isn't as much about the bike leg of your race as it is with the run. Thanks to how the tri bike engages your upper body to conserve your leg muscles, you'll start the run a bit fresher, potentially saving you time on the run. This is because on a triathlon bike – also achievable (to an extent) on a road bike with aero bars – you won't be overextending your hips and leg muscles.

This is supported by science. In an , researchers found that triathletes performed significantly better on the run after completing the bike course on a triathlon bike. This was due to biomechanical changes including:

• Increased plantar flexion and reduced range of knee motion on the bike, leading to greater stride length on the run;
• Reduced hamstring activation, conserving energy for the run;
• Less calf use on the tri bike, again saving energy for the run.

Fitting your bike: 3 mistakes to avoid on triathlon and road bikes

Both the bike mechanics and your body’s response to riding a tri bike point to the advantage of using a triathlon bike to gain speed during the cycling part of a triathlon and the run portion of the race. However, you need to ensure that your tri bike is well fitted and that you're confident and comfortable on it before race day. Otherwise, you won’t benefit from speed gains, and you'll risk going slower or even injuring yourself.

Triathlon expert and bike fitting specialist, Matt Bottrill, warns that one of the biggest mistakes athletes make when getting a tri bike is simply not practicing enough on one or just showing up ready to race without fitting it properly. Here’s what to look out for with your new tri bike.

Make sure you can control the bike

Your upper body is much further forward on a tri bike than on a road bike; even the gears and brakes are positioned differently. You need to become familiar with this position and get your back and shoulders acclimated to the different stretches that the aero position requires. 

You also need to ensure your fingertips are at the top of the tri bars for best positioning. 

Here’s Matt’s advice for getting it right: “Sit in front of the mirror and get the aero bars to a vertical level. What you’ll start to see is that you will rotate your shoulders into place.” 

Adjust slowly until you’re in the optimal position. For many, this will also take a lot of the stress out of the neck and shoulders area. The combination of elbows and hands, referred to as the "cockpit" in triathlon cycling, helps prevent a big rolling of the back. You'll be safer on the road because you're not looking down but retain the ability to follow the road ahead.

Don’t forget the saddle

A classic mistake people make on a tri bike is not adjusting their saddle position. This happens to both tri bike users and road bike users after they’ve fitted aero bars to their bike. 

Once you have the tri bars, your body will naturally move forward and over the handlebars, so your saddle also needs to move forward and face down to follow your body naturally. Begin your bike fitting by adjusting your seat height, starting as high as possible while you can extend the leg without dropping the hip. 

The next step is to adjust the cleats by moving them forward and backward, so the central spindle of the pedal goes through the ball of your foot. You need to end up a bit more angled so there’s no pressure on your ankles and knees until you feel as “natural” as you can.

Combining good saddle and cleat positioning gets you in the best position on the bike without causing undue stress and pain during your triathlon.

Practice, practice, practice

It’s likely you won’t get your bike spot-on from the first try. Just like you’ve practiced weeks and months to be at ease on your road bike, you need to allow time for your body to adjust to the tri bike and to develop the muscles and flexibility that will put you in the best possible position come race day. So, the third big mistake people make when fitting their tri bike is NOT practicing and adjusting!

When you’re cycling on a tri bike, your whole body is forced into a different position from the road bike. On the tri bike, you’ll always be bent over in an aero position AND also extended forward on the tri bars. Your hips are more open thanks to the geometry of the bike, mimicking the position you’d have on a road bike without the aero tuck.

At the same time, you’ll also use your upper body significantly more on the tri bike, as you control the bike with your elbows.

From becoming acclimated to the feeling of the tri bike to learning how to handle it while becoming more comfortable is a good two to three months of consistent practice. Build in intervals with your road bike with aero bars, like 5 to 7-minute intervals in that aero position with equal rest intervals in between. For example, if you’re down in the aero position for 5 minutes, your rest intervals out of aero should also be 5 minutes.

Four to six weeks out from a race, I shift entirely to the triathlon bike with rides in the aero position for two or more hours. This allows you to really dial in that positioning down on the aero bars. Focus on riding your tri bike for all your long rides while continuing other rides on a road bike (for example, a leisurely group ride and an interval session mid-week, vs. a long 3-plus-hour session on Sunday).

Finally, Matt Bottrill also warns about the danger of using a tri bike and not looking ahead - it sounds silly, but it’s true! Matt says, “Most triathletes have a bad reputation to crash because they’re always looking at the floor.” So, get used to your head positioning and always look ahead. 

What about the road bike?

On a road bike, you won’t have the same concerns around body positioning. Many triathletes opt for putting aero bars on their road bikes instead of racing on a tri bike. This is especially useful if you need a more responsive bike with explosive power, for example, on a course with a lot of gear changes, climbs, and stops and starts. Road bikes are also better handlers on technical courses.

This is why you would be well-served by adding aero bars on a road bike before making the transition to a tri bike. Aero bars allow you to lean into that aero position during your triathlon but also retain the option to straighten your back and adjust your body more, all while giving you a better ride on technical courses.

However, if you fit tri bars on your bike, Matt warns that, again, you need to practice getting used to the aero position and having to move to switch gears and brake. Start with the same interval training mentioned above to get your body used to the aero position and progress gradually up to race day.

If you’re looking for more advice about when to use a tri bike vs. a road bike and how you’ll benefit from each, check out our article on two situations when a road bike can be faster than a triathlon bike. 

Choosing the bike shoes for your next triathlon

We’ve talked about your bike choice and how it can impact your body and your time in an Ironman or shorter distance triathlon. What about shoes? Should you wear tri bike shoes, or will any “regular” bike shoes do? What’s the difference between tri bike shoes and road bike shoes, and is it the same thing as with road bikes vs. tri bikes?

This makes them a good choice for shorter triathlons, where every second counts. Also, you’ll notice a lot of professional triathletes don’t wear socks, especially at shorter distances. Triathlon bike shoes are designed to accommodate that by ensuring you’re not going to get blisters and chafing from sweat and drinks spilled over your shoes while you’re cycling. 

Tri bike shoes breathe better, but recently, we’ve seen that wearing triathlon socks is actually offering a few watts savings… so the debate continues. Road bike shoes are also getting less stiff and easier to use, so wearing them with tri socks could be the winning combination for you.

Long story short, you should wear the shoes you’re comfortable in. Whatever you choose, I strongly recommend clipping in and not using something like mountain bike shoes or flat pedals; you risk slipping off with sweat, rain, etc. Yes, it takes some getting used to, but clipping into your pedals is safer and faster.  

Which takes us back to the idea of practicing with your kit before race day, so you know what works best. 

Getting ready for race day 

With a well-fitted triathlon bike, you’ll be faster on a flatter, straighter course, but you need to be comfortable with the tri position and also confident and adept at handling the bike. So, we’ve mentioned a few mistakes to avoid, but you'll also need to consider the bike course when preparing for race day.

If it looks like you’re headed for a twisty, technical course with lots of stops and starts where your bike-handling skills will be tested, I advise going for a road bike with aero bars. But don’t just clip the aero bars on and head out! Practice with them just like you would with a tri bike. 

As for the best investment in bikes, remember that a triathlon bike isn’t as safe or as versatile as a road bike. You won’t be accepted into most group rides with a tri bike because of the safety issue, and you won’t be able to easily switch ties to try out gravel riding. For a road bike with big tire clearance, you can install gravel wheels in winter, or you can change to deep-section wheels and add on aero bars for your triathlon race. 

Read more

• Find out how much time you can save by using a tri bike vs. a road bike.
• Continue to train safely during pregnancy.
• Start using your work commute for bike training for your next tri. 

About the contributors

Matt Bottrill has won multiple National Championships and holds many competition records. He coaches some of the world’s top athletes on a range of stages. Matt Bottrill Performance Coaching, open to coached athletes, features all ages and abilities. Over the last few years, the team has achieved many titles, including individual, team medals, and records in National Championships and many PB’s. Contact Matt on his website and social media.