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Triathlon Bike vs Road Bike: Understanding the Differences

by Zach Nehr

Blog ▸ Triathlon Bike vs Road Bike: Understanding the Differences

Zach Nehr

Zach Nehr

Zach has a degree in Exercise Science and Psychology. He is a certified coach, Cat 1 cyclist, and is a freelance writer having been published in many of the worlds largest endurance sports publications.

Take a triathlon bike vs road bike, and you can immediately tell the difference. A road bike has thinner tubing, drop handlebars and more relaxed geometry. On the other hand, a tri bike has thick and aerodynamic tubing, long aero bars, and aggressive geometry. 

But what does that mean? 

What Makes a Road Bike Different From a Triathlon Bike?

Road bikes and triathlon bikes aren’t the same, but why? This article will look at the differences between road and tri bikes, including frame geometries, aerodynamic handlebars, and riding positions. 

A triathlon bike is not always faster than a road bike. In another article, we looked at Two Situations Where a Road Bike Becomes Faster Than a Triathlon Bike.

The Purpose of Triathlon Bikes and Road Bikes

Before we look at the differences between triathlon and road bikes, we must know what each bike is used for. 

Triathlon bikes are used for triathlons, while road bikes are used for road riding. But let’s dig a little deeper. 

Triathlon bike courses are typically flat and straight. You will sometimes find bike courses with hills or technical turns, but you should never be descending a mountain on a tri bike. Triathlon bikes are designed to go fast in a straight line. Thus, they are super aerodynamic and stable, though they are not ultra-light like some road bikes. 

Road bikes are designed for all kinds of road riding, from criterium racing and group rides to mountainous races such as the Tour de France. They are meant to go fast in a straight line, but they are also designed to be incredibly quick through corners. You can throw a road bike during mountain descent or a town sign sprint. Road bikes are also light for hilly courses and 10-mile mountain climbs. The best road bikes come right around the UCI’s (cycling’s international governing body) weight limit of being no lighter than 6.8kg (15 lbs). 

group of men on cycling race

Remember those facts as we compare and contrast triathlon and road bikes. Remember: tri bikes go fast and straight, while road bikes can climb, sprint, descend, and everything in between. 

If you’d like to listen to this topic, you can check out our podcast episode, Tri Bike Versus Road Bike.

Here’s what we’re going to cover in our comparison of tri bikes and road bikes:  

Triathlon Bike vs. Road Bike:

  • Physical Differences in Triathlon Bikes and Road Bikes
    • Triathlon Bike Frame
    • Road Bike Frame
    • Aero Bars and Handlebars
    • Saddle and Seatpost
    • Wheels
    • Tires
    • Gearing
    • Brakes
    • Drivetrain and Components
  • Why You Should Start With a Road Bike
    • Beginner Road Biking Position
    • Adding Clip-on Aero Bars to Your Road Bike
    • Group Rides
    • When Should You Make the Switch to a Triathlon Bike?

Physical Differences in Triathlon Bikes and Road Bikes 

Now that we know what triathlon and road bikes are used for, we can take a closer look at the physical features that separate their frames. It’s not just how you ride the bike but also how it is designed. 

Triathlon bikes are meant to be ridden in an aggressive, forward aero position. In contrast, road bikes are designed for all-around road riding. First, let’s look at tri bike frames versus road bike frames. 

Triathlon Bike Frame

Triathlon bikes typically have a much steeper seat tube angle, which is the angle between the seat tube and the horizontal plane. Thus a 90-degree seat tube angle would mean that the seat tube is pointing straight up or perpendicular to the ground. You can use the level ground as the horizontal plane. 

Triathlon bikes generally have a steep seat tube angle of around 75-78 degrees. This pushes the rider’s position down and forward. This allows a triathletes hips to open up while in the aero position, preventing the athletes from starting the run with tired legs from being scrunched on the bike.

Triathlon bikes are designed to enable triathletes to ride in a more forward position. Thus, a tri bike’s geometry reflects its steep seat tube and seat post angle. There may also be some subtle differences, such as the longer effective reach on a triathlon bike. 

With your arms in the aero bars, your body will be much more stretched out on a tri bike compared to a road bike. On the horns or the part of the aero bars that stick out to the sides and house the brake levers, your reach should be very similar to your reach on road bike handlebars. 

A triathlon bike frame is typically heavier and more aerodynamic than a road bike. The frame will have thick tubing that is aerodynamically shaped to be super-fast in a straight line. Since most triathlon bike courses are flat, the aero gains from the tubing typically outweigh the weight penalty of having a slightly heavier frame. 

In this article, we took a look at the Best Beginner Triathlon Bikes.

Road Bike Frame

man witha road bike

Road bikes have a shallower seat tube angle compared to triathlon bikes. While a tri bike’s seat tube angle may measure 75 to 78 degrees, a road bike typically has a seat angle of around 72 degrees. This shallow seat tube angle pushes the rider’s position back. It is more upright, making for a more comfortable and controlled but less aerodynamic position.  

Designed for cornering, mountains, and sprints, road bike frames are typically designed as strong all-rounders. However, there are more “specialized” road bikes than ever before, such as aero road bikes or climbing road bikes. These frames feature subtle differences in the tubing and overall weight. Still, their performance on mixed terrain is nearly the same. 

Road bike frames use thinner tubing than tri bike frames to save weight and add versatility. Extreme aerodynamic tubing can affect a bike’s center of gravity and its performance in corners. For this reason, most road bikes feature medium-thick or thin tubing that is simultaneously aerodynamic, lightweight, and nimble. 

Aero Bars and Handlebars

man in orange jacket riding bicycle on road during daytime

A tri bike can always be distinguished by its aero bars which stick out in front of the frame. These aerodynamic bars can be adjusted fore and aft, side to side, and up or down. Either way, they will always stick out in front of your triathlon bike’s frame. 

When using a triathlon bike’s aero bars, your forearms will be placed inside each bar, typically containing a padded groove. Your back should be nearly flat (i.e., parallel to the ground) with your hips rotated forward on the saddle. This allows you to put power into the pedals while holding your body in the aero position. 

Your shifters are typically on the ends of your aero bars, while the brake levers will be on either side of the horns, sometimes called the base plate of the aero bars. This is one of the biggest reasons that a tri bike is not recommended for group riding because of the time it could take to get your hands from the aero bars to the brake levers. 

Aero bars allow you to maintain an aerodynamic position that reduces drag and increases your speed for the same amount of power. 80-85% of the total aerodynamic drag that you have to push through on the bike is caused by your body’s position. Thus, the smaller you can make your body’s frontal plane (the portion that hits the wind and causes drag), the faster you will be able to go at the same power.

In other words, get more aero, reduce your aerodynamic drag, and go faster without using any more effort.

The aero position can be very uncomfortable, especially for beginners. Your upper body will be held tight together while your arms are in the aero bars. We recommend starting with a road bike and adding clip-on bars before going all-in on a tri bike. 

By contrast, road bikes have drop handlebars which are curved handlebars with three main hand positions: tops, drops, and hoods. 

The tops are near the center of the handlebars on either side of the stem. This hand position is best for climbing as it puts you in an upright position that opens up your chest and maximizes breathing efficiency. The top position is the least aerodynamic hand position, which is why climbing is recommended when aerodynamic drag matters less than power output. 

The drops hand position is the lowest and most aggressive hand position for road cycling. You can place your hands on the bottom curve of the handlebars for sprinting, racing, and aggressive cornering. The drops position can be demanding on your arms and lower back, so we do not recommend riding in the drops for the entirety of a long endurance ride. 

Lastly, the hoods hand position is the most common road cycling position. In this position, your hands are wrapped around the top of the curve of the handlebars, right around the brake levers. Riding on the hoods is a neutral cycling position that is neither aggressive nor upright. We recommend riding on the hoods during most road rides, especially during group rides, since you have easy access to the brake levers. 

Wheels

Triathlon bikes typically have deep-sectioned wheels, meaning the rim is quite thick. The ultimate version of a deep-sectioned wheel is a disc wheel filled in from the edge of the rim to the wheel’s hub. 

Most competitive athletes will use a rear disc wheel as long as the bike course is relatively flat and not too windy. Disc wheels can blow you around in high winds, but they are significantly faster than other types of wheels in calm weather. 

The only caveat is that disc wheels are only faster at speeds above 30-35kph. Below that speed threshold, disc wheels can actually be detrimental to performance. In addition, disc wheels are definitively slower on courses with lots of corners because it takes significantly longer for a disc wheel to get up to speed.

Amateur triathletes typically use deep-sectioned carbon wheels for triathlon, which maximizes their straight-line speed without blowing up their bank account. (Disc wheels can be costly). In 99% of triathlons, deep-sectioned carbon race wheels are on everyone’s triathlon bikes. 

In contrast, road bikes typically have carbon wheels for racing and aluminum wheels for training. Road cyclists only use deep-sectioned carbon wheels in flat criteriums or road races. Road cyclists will often use shallower carbon wheels for hilly races or lightweight climbing wheels for mountainous races. These wheels are much less aerodynamic but significantly lighter than deep-sectioned wheels. 

To put some numbers on it, deep-sectioned road wheels typically clock in around 40mm in depth. Deep-sectioned triathlon wheels, in contrast, are significantly deeper at 60-80mm. At higher speeds and on straighter courses, some triathletes will use disc wheels which are the entire depth of the rim.

For experienced triathletes who can average more than 35kph on the bike, disc wheels can add 0.7-1kph of speed on a straight and flat triathlon course. In most other cases, a disc wheel is more likely to be detrimental to your triathlon performance.

Gearing

Triathlon bikes typically have a narrower gear range than road bikes because of their intended terrain. With few hilly triathlon courses, there is rarely a need to have a “granny gear” such as a 34×34 on a tri bike. 

On a flat course, you’ll never be going slow, so there is no need for a small front chain ring. In fact, many triathlon bikes come with a 1x set-up, which means there is only one front chain ring. Eliminating the small ring also saves weight by removing the chain ring and derailleur and lessening your chances of dropping your chain. 

On the other hand, road bikes typically have a wide range of gearing for flat riding, sprints, criteriums, and hill climbs. Nearly all road bikes come with a 2x set-up, which is two front chainrings. You can find large cassettes on modern road bikes, including 11-speed or 12-speed set-ups such as a 53×11 or 50×10 cassette. 

Brakes

Most modern triathlon bikes and road bikes come with disc brakes. Older bikes will probably have rim brakes which are slightly lighter, cheaper, and easier to service than disc brakes. However, disc brakes are more powerful than rim brakes. Disc brakes also perform better in all weather conditions. 

In terms of aerodynamics, disc brakes and rim brakes are basically identical. You may lose a second or two over 40km on disc brakes, but you could easily make up that difference by braking better and cornering faster. 

Why You Should Start With a Road Bike

black road bike

Beginner cyclists should always start with a road bike rather than a tri bike. Road bikes are more versatile and comfortable than triathlon bikes. They are also cheaper and easier to find, especially in the correct size for you. 

Beginner Road Biking Position

Road bikes are also safer than triathlon bikes. As we have seen from the handlebars and riding position comparison, road bikes are much more upright than triathlon bikes. Their handlebars are also wider, and there are a wide variety of hand positions to choose from on the tops, drops, and hoods. 

These positions give you more control over a road bike, and it is easier to brake and react on the open road.

Adding Clip-in Aero Bars to Your Road Bike

Once you’re ready to start training in the aero positions, you can buy a set of clip-on aero bars which you can attach to the tops of your road bike handlebars. With clip-on aero bars, you’ll be able to train in the aero position while also having the option to use your road bike handlebars for additional comfort and stability. 

Group Rides on a Road Bike vs. Triathlon Bike

Road bikes are much better and safer for group riding than triathlon bikes. In fact, some group rides ban triathlon bikes because of safety factors. 

Starting with a road bike allows you to get into the sport of cycling and improve both your fitness and bike handling skills. The more upright position and multiple hand grip positions allow you to learn cycling, cornering, and group riding with more confidence. 

When Should You Upgrade to a Triathlon Bike?

We only recommend purchasing a triathlon bike once you are comfortable cycling and you are committed to the sport of triathlon. Before then, a road bike is only marginally slower than a triathlon bike, especially with a good set of clip-on aero bars. 

Road bikes also give you more comfort and confidence, so they are often better for beginners who are still learning how to climb and corner on the bike. Once you are dedicated to triathlon, it is worth looking at a triathlon bike that will be quicker in a straight line, and especially quicker for long and flat bike courses. 

Zach Nehr

Zach Nehr

Zach has a degree in Exercise Science and Psychology. He is a certified coach, Cat 1 cyclist, and is a freelance writer having been published in many of the worlds largest endurance sports publications.