Save Nearly 20 Minutes on Your Next Ironman Bike Leg by Swapping Out This One Piece of Equipment

When it comes to the bike leg of your triathlon, the more aerodynamic choice for speed and performance is a triathlon bike. However, you can still maximize your positioning for faster times with your road bike.

It's true that a triathlon bike, with its aggressive positioning, aerodynamics, and geometry, is faster than a road bike. All things being equal, of course, the tri bike wins on speed increase, but by how much? Well, that really depends on a few things.

In this article, we’ll explain exactly:

• How much faster a triathlon bike is than a road bike;
• The benefits of sticking aero bars on your road bike;
• If you even need a triathlon bike at all; and
• Whether you should be using a triathlon bike or road bike for your next event.

How much faster is a tri bike than a road bike?

The farther you go, the “faster” a tri bike becomes over a road bike. For example, as I discovered during , sustaining 150 watts of power is a couple of kilometers per hour faster on a triathlon bike. What starts as a roughly two-minute speed bump in a sprint-distance triathlon compounds the farther you go. That means you'll save nearly 20 minutes throughout a 112-mile Ironman bike leg.

Think about it. Simply swapping your road bike for a tri bike in your next Ironman can save you that extra time toward a new Personal Best. In my experiment, the triathlon bike's 210 watts of power speed benefits for the triathlon bike were largely unchanged. 

So, going back to which one is faster, it would seem that the tri bike wins hands down. Let’s have a look at what makes the tri bike faster in a race, especially thanks to what it enables you to do in a triathlon once you hop off the bike. 

The hip angle at which you sit on a triathlon bike is about 90-degrees, while the angle on a road bike is closer to 80-degrees, which is important because the former places less stress on your glutes and hamstrings. This is beneficial when you hop off the bike and begin the run portion of your race.

Closing off the hip angle by placing yourself in an extremely aggressive position is detrimental to your overall performance. Thanks to riding a triathlon bike, your legs will be fresher, and your hips will be less sore when you begin your run. Your calf muscles also get a break thanks to your foot positioning on a tri bike, which is an added bonus for the run. 

To sum it up, there are two ways in which riding a tri bike makes you a faster triathlon finisher:

• A tri bike enables you to ride faster in a straight line at the same power output as a road bike;
• Thanks to your body positioning on the tri bike, your hips and legs will be fresher and stronger for the run leg when you finish the ride section of a triathlon. 

Should I put aero bars on a road bike?

Triathlon bikes can be expensive and a big investment to make unless you’ve fully committed to the sport. While you’re starting out, triathlon bike fitting experts like Matt Bottrill agree that you can compete on your road bike. But there’s one great improvement you can make to your road bike to get faster in triathlon: adding aero bars.

The aero position makes you faster because the body leans forward onto the handlebars, and reducing the drag from your upper body when you’re riding fast. 

Once you've established yourself as a recreational cyclist, have a road bike you're familiar with, can bike long rides on, and can safely control, you should consider mounting aero bars before competing in a triathlon. While the bike leg generally takes three to four months of triathlon training, make sure you factor in enough time to practice on the tri (aero) bars before race day.

If you plan to stick with your road bike during a race, Matt Bottrill, cycling coach and time trial specialist, says adding the aero bars will provide the biggest time-saving benefit.

Fitting tips for tri bars on a road bike

Ensuring your tri bars fit correctly is key to getting you riding faster. Here’s what you need to know.

Ensure that your fingertips reach to the tip of the aero bars, so you’re not overextending yourself to get to the end. At the same time, your elbows should be touching the pads to give you more control and stability over the bike.

Matt offers this piece of additional advice to ensure you have the positioning right.

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. 

One common mistake many people make with adding aero bars to their road bikes is not adjusting their saddle position. Adding the bars will naturally pull you forward, so if you don’t slide the saddle forward to compensate for that, you’ll develop low back pain.

When to use a tri bike vs. road bike

A triathlon bike positions you differently than a road bike, requiring you to use different muscles. This is a good thing! It helps develop fitness and muscle strength in various situations that underscore the essentials of cycling: a stronger core and lower body for improved performance and bike handling.

I like to call this your overall "bike depth." It helps you prevent injury by increasing adaptability to changing terrain and weather conditions, not to mention more subtle variations that most of us are not even aware of. Proper positioning demands less energy and focus, so you can continue to bike faster. 

From a safety standpoint, as soon as you have the confidence to ride in a group, you’ll need a road bike. Triathlon bikes aren’t nearly as safe or easy to handle as a road bike because you have to continuously move your hands back and forth to shift and brake. Therefore, tri bikes are generally frowned upon or even prohibited in a group setting.

I’ve noticed that switching up the bike I’m riding throughout the year helps me stay mentally engaged. Sure, I may be sacrificing some tri bike-specific fitness gains by hopping on the road, gravel, or fat bike at different times and in different seasons, but this keeps me stimulated and excited to continue riding—and that's no small thing. If I were stuck on the triathlon bike day after day, I'd lose any and all desire to get in the saddle as often as I do.

Here’s how to determine when to use your triathlon bike or road bike. If you’re riding in a group, road bike every time. Then, as you start to approach race day, two to three months out, get on the triathlon bike more consistently. This allows you to work out your positioning and get more comfortable in the aero position to sustain it for longer distances.

To do this, start with five to seven-minute intervals in that aero position with equal rest intervals in between. For example, if you’re down in the aero position for five minutes, your rest intervals out of aero should also be five 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 to do your other rides on a road bike (for example, a leisurely group ride and an interval session mid-week, vs. a long 3-plus hours session on Sunday).

After the race, it’s back to mixing in the different bikes and terrain to continue building general fitness and allowing the body to adapt to different situations.

Do I need a triathlon bike?

Short answer, no. You don’t need a triathlon bike to train for a triathlon or even compete in one. 

• Use the bike you have access to. 
• If you’re just starting in the sport, the road bike gives you more opportunities off the bat. 
• Group rides are easier and safer on a road bike. 
• You'll have more flexibility during a ride, allowing you to move and stretch your back more often.
• Road bikes are easier and safer to handle on twisty or stop-start routes. 

For all these reasons, a tri bike is not necessary to begin your cycling training for the first few triathlon races. I recommend clip-on aero bars to improve your aerodynamics and practice with them so you’re comfortable on race day. 

Once you’ve committed more fully to triathlon as your main sport, and you want to chase some marginal gains, that's the time to look into triathlon bikes. Even then, consider whether you need a tri bike depending on the course. 

Course specifics

If you are preparing for a triathlon with a fast, flat, straight bike course, where you won’t need to do much technical riding, and you want to go as fast as possible, you might be well-served by investing in a tri bike. 

While that's sound advice, look at the 2019 Ironman 70.3 World Championship in Nice, France, Gustav Iden won it while using a road bike.

Now, it’s important to mention that it was the only bike he had; however, the championship field was littered with many others electing to ride road bikes over tri bikes because of the repeated climbing and technical nature of the course requiring skillful handling.

Riding your course, if you’re able to before the race, provides a lot of insight into the type of bike you should ride on race day. But, if you can’t visit the place twice, at least watch videos from previous races and study the map and course profile. That will suffice to help you make the right decision about whether to ride a road bike or a tri bike. 

Tri bike or road bike for Ironman (triathlon, sprint distance, Olympic distance, half ironman)

Triathlon bikes and their aerodynamic and geometric advantages are generally faster than road bikes. There isn’t much debate between the two in terms of speed over the distance of a triathlon bike leg when all variables are considered equal, as we’ve seen so far. However, there are two specific instances when you’d be faster upright on a road bike than on a tri bike.

Comfort and confidence, or lack thereof, are two significant differentiators between riding a tri bike and a road bike, regardless of the course length. If you cannot get into a comfortable, more aerodynamic position on a tri bike, then you’ll be faster on a road bike.

Road bikes are specifically designed for longer rides, allowing you to sit more upright and relaxed. They are, therefore, a better choice for longer courses, especially if they include a lot of twists, turns, and technical terrain. 

Additionally, on a triathlon bike, you’re placing a lot of pressure on your upper body as you get down into an aerodynamic position. You need to practice this position to strengthen your core and shoulders to support riding on a tri bike. At the same time, your position on the tri bike will save more strength and flexibility in your legs for the running portion of the triathlon. 

As for the ability and confidence to handle a triathlon-specific bike, if you don’t have experience with one, you’ll always be better off on a road bike. This is why we suggest using a tri bike progressively, getting familiar with it for longer rides, and developing bike-handling skills specifically for the tri bike (adapting your style to account for the different body position with your weight over the front wheel). You should practice with a tri bike for at least three or four months during your long rides before the race.

Overall, you will be faster on a triathlon bike as long as the bike route is relatively straight and flat. If you continue triathlon training and competitions, you should aim to get comfortable and confident on a tri bike as well as the road bike. The ability to switch between them is the ideal goal over time. 

What you should do next…

Deciding on your next steps can feel overwhelming. If you love riding and racing with your road bike, keep doing that! If you’re looking to get a little faster without having to purchase an entirely new bike, simply add aero bars (under $100) and enjoy the instantaneous speed gains!

If you stick with your road bike with aero bars, make sure you practice your aero position to effectively ride on the tri bars before race day. If you’re looking for an affordable way to up your triathlon game by investing in equipment, then aero bars are relatively cheap and will save you time on your next Ironman bike leg. 

If you have a triathlon bike, the best thing you can do to improve your speed and performance is to maximize your comfort level with body positioning. These ergonomics also include using the brakes and shifting gears, adjusting your saddle and cleats, etc. Once you can be comfortable on a tri bike for a long ride of 3-4 hours-plus, you’ll start to experience the advantages of the aerodynamic design and the speed gains you’ve been wanting. 

Read more

• Triathlon Bike vs. Road Bike: Two Situations Where a Road Bike Becomes Faster Than a Triathlon Bike
• Learn how to develop strength for triathlon performance
• Check out our guide of triathlon watches for beginners

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.