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What Is the Difference between a Road Bike and a Triathlon Bike?
By Tom Demerly.

One of the most common questions in our store is: “What is the difference between a road bike and a triathlon bike?"

That is a good question to ask if you are shopping for a bike for more than one type of riding or can't decide which bike you should buy.

What if you want a bike for standard road riding but also want to do some triathlons? Many people think a triathlon bike is only good for riding in triathlons. As we will see, this is not necessarily the case. Triathlon bikes are well suited for any type of long distance solo road riding where comfort and efficiency are the primary concern.

Standard Road Geometry Bike

Triathlon Geometry Bike

If you own a road bike and are considering doing triathlons on it, it is important to understand the advantages and limitations of standard road geometry bicycles in a triathlon setting. It is also worth understanding the limitations and benefits of a triathlon bike in a road riding setting.

Simply stated:

A triathlon bike is specifically designed to be ridden comfortably and efficiently in the aerodynamic position using elbow-rest style aero handlebars. Triathlon geometry bikes facilitate the transition from cycling to running better than road geometry bikes.

Using aero handlebars on a triathlon geometry bike provides two benefits:

1. Improved aerodynamics with better comfort/efficiency.

2. Easier transitions from bike to run.

Aero handlebars allow the rider to sit lower on the bike and with a narrower, more aerodynamic upper body cross section. As viewed from the front, the rider’s body is narrower than having the arms spread out to normal drop handlebars. The rider’s upper body is supported by the skeleton while using aero bars (resting on the elbows), while on the standard road, drop handlebars a rider must rely on the use of upper body muscles to support their body and maintain the riding posture. Visualize the difference between leaning on a counter with your elbows (easier) and supporting your torso over the counter in a kind of “half push-up” posture (harder).


On a road bike you will use mostly muscular effort to support the weight of your torso on the handlebars.

It is easier to support you upper body on a correctly fitted triathlon bike. This reduces the amount of muscular effort required to sit on a triathlon geometry bike, replacing muscular support of the upper torso with skeletal support.

Bolt -on aerobars as used on a triathlon bike.

The critical elements to maximizing the benefits of a triathlon bike are fit and position. Installing aero handlebars on a standard road bike (as opposed to a tri bike) exerts two changes on a rider’s position: The rider’s upper torso is more stretched out with the hands and elbows farther forward, and the angle between the femur (thigh) area of the leg and the torso becomes "sharper" or more acute. There is less distance between the thigh and the torso at the top of the pedal stroke. These two changes mean the a road bike with aerobars becomes less comfortable. Because of the close proximity of the femur (thigh) to the torso (chest/stomach/abdomen) at the top of the pedal stroke (10 o’clock to 2 o’clock pedal position) the rider will feel too "cramped". At the same time the increased distance from saddle to aerobars on a road bike usually makes the rider too stretched out for stable handling.

This is more than just a sensation. This tight angle from femur to torso can prevent the rider’s diaphragm from contracting fully and make efficient breathing more difficult. Additionally, there is an increased amount of flexion in the gluteus muscles and the semimembranosis (hamstring) muscles on the back of the leg. This means they cannot contract as powerfully. More problems associated with fitting aero bars to a road bike are lower back pain, mostly from a position that is too stretched out and increased saddle discomfort.

A triathlon bike is specifically designed to eliminate these problems. The angle of the seat tube on a triathlon bike is typically 76-78 degrees. A typical road bike seat angle is 73-74 degrees. This steeper seat angle serves to open the distance between the thigh and the torso up, easing muscular tension in the legs and lower back and making breathing easier.

Differences between Road and Tri Geometry Frames.

There is a common misconception that the seat on a triathlon bike is "farther forward". It is not. The fact is the bottom bracket is relatively farther back. This puts the rider’s feet farther back, opening up the torso/femur angle.

Another attribute of some smaller frame size triathlon bikes is the 26" or 650c wheels. Some people mistakenly think these wheels are on triathlon bikes because they are "more aerodynamic". They are no more aerodynamic (comparing wheels built using the same components) than 700c road wheels.

Some smaller frame size triathlon bikes use 26" or 650c wheels because of the 78 degree seat angle. The distance between the rear tire and the seat tube of the frame would not be great enough for a 700c wheel to fit. Most frame sizes above 52 or 53 centimeters use 700c wheels with triathlon geometry. Earlier versions of triathlon bikes made more widespread use of smaller wheels.

A triathlon bike frame has a shorter top tube to accommodate the use of aero bars. Triathlon bikes also have a lower head tube to allow for the extra height of aero bars, so the rider can maintain a lower upper body position. Some triathlon bikes have very low head tubes, others slightly higher. Matching the height of the head tube to your desired handlebar to seat drop is another important consideration in finding your optimal bike.

Riders who install aerobars on a road geometry bike usually wind up with too much distance between the saddle and the handlebars. On a road bike this usually means the rider will slide forward on the saddle when using their aerobars, eventually sitting on the front 1/3 of the saddle. Riding in the aero position usually means rotating the pelvis farther forward and using the nose of the saddle on both a road bike and a triathlon bike, but a triathlon bike is built with the shorter top tube and slacker head angle to facilitate this posture more comfortably and with greater stability.

On a road bike the top of the head tube is nearly horizontal to the top of the seat tube and seat cluster area. When aero bars are installed the front of the bike is now so high it is difficult for the rider to get a comfortable, low, efficient position. Triathlon bikes have lowered top and head tubes to make room for the elbow pads of the aero bars.

Your biggest benefit from using a triathlon bike is likely to come during the run, after your second transition from bike to run.

These technical differences between triathlon bike frames and road bike frames make the triathlon bike more comfortable and efficient while using aero bars. An additional benefit is improved running performance off the bike as compared to riding a standard road bike and getting off to run. Lower back muscles are less cramped and fresher for the bike/run transition. Your transition from bike to run will be easier, especially in the first 1-2 miles of the run.

The difference in performance for you between a triathlon frame and a road frame in a triathlon setting can be substantial. Entry level cyclists will benefit the greatest from a triathlon geometry bike. It is not unusual for a customer who is riding 40 kilometers (24.8 miles) in 1:10:00 on a standard road frame equipped with aero bars to switch to a triathlon frame and be able to do 40 kilometers in 1:06:00. The more experienced the cyclist, the less advantage will be appreciated. Novice triathletes and cyclists will notice big gains in performance and comfort.

In 2000 the Garside Study revealed that athletes can run faster after riding a triathlon bike than after riding a road bike over the same distance.

The secondary advantage to a triathlon bike is easier transitions from bike to run and faster running. Ian Garside and Dominic Doran published an interesting study in June of 2000 in the Journal of Sports Sciences. The study is known as “The Garside Study” and is used in triathlon bike fitting schools such as Dan Empfield’s Fit Institute of Slowtwitch (F.I.S.T.). The Garside study tested athletes in a biomechanical setting, in other words, aerodynamics on the bike were not a factor in the results: Aerodynamic benefits would be in addition to the biomechanical benefits from a triathlon bike. Test subjects performed a 40 kilometer (24.8 mile) time trial on a road geometry bike in a stationary trainer followed immediately by a 10 kilometer (6.2 mile) run on a treadmill. Later the same test subjects repeated the test protocol but used a triathlon geometry bike on the stationary trainer then transitioned immediately to the treadmill for the 10 kilometer run. Time savings for athletes running off the triathlon bike were enormous: They averaged a full 5 minutes time savings on the 10 kilometer run when they transitioned off a tri bike as opposed to transitioning off a road bike. Simply put, you’ll run faster and more comfortably off a triathlon bike than a road bike.

While triathlon bikes offer a strong set of advantages for anyone wishing to ride comfortably in the aero position, it is important to be familiar with the limitations of the triathlon geometry.

Triathlon frames are at their best when riding on flat to rolling terrain (like most of Michigan, Northern Ohio, Indiana and Illinois), where there is no need for high speed cornering, and where the cyclist will not be relying on other riders to draft off of. If comfort and efficiency are your primary concern, a triathlon geometry frame may be a good choice.

If this is how you ride, a triathlon bike is right for you.

Triathlon frames are not intended for use in group rides where drafting at close proximity and lightening fast handling are important. Triathlon frames are not optimized for high speed cornering, such as criteriums. Triathlon geometry bikes climb best when using a different technique than road climbing.

In Dearborn, where our store is located, there is a training ride every Wednesday night that is well attended by different types of cyclists; mountain bike racers, tourists, road racers and a strong contingent of triathletes. It is a fast-paced pack ride through a suburban setting with 11 stoplights and 14 corners taken at high speed in a group. The distance is 24.3 miles. Although it is a fast group ride where drafting is important to stay with the ride, many triathletes do the ride on their triathlon bikes. This is testimony to the versatility of the triathlon bike, but also an acknowledgement of its limitations as there are occasional crashes which can be attributed (in some part) to the handling limitations of triathlon bikes.

If you are having difficulty deciding whether you should own a triathlon bike or a road bike, and you only want to own one bike, think about this:

  • If the primary reason you are buying a bike is to participate in multisport (triathlon or duathlon) events and do solo training rides- Buy a triathlon geometry bike.
  • If the primary reason you are buying a bike is to participate in group rides or races, buy a standard road bike.

While there is some crossover use for each of these bikes, if you buy the wrong bike the money you spent on it could have been better used on a more appropriate bike.

The most typical scenario with entry level customers is for them to buy a standard road bike, find out they enjoy participating in multisport events, and then buy a triathlon bike several months later. In most cases the customer may have been better served to buy an appropriate triathlon bike first. Many multisport athletes also buy a road bike after a season of triathlons so they can participate in group rides more readily. It isn’t unusual for road riders in large group rides to be somewhat reluctant to allow triathlon bikes on group rides.

Realistically, the ability to ride well in a group is more dependent on the rider than the bike, but entry level riders new to group riding and drafting may have a more difficult time learning to draft in a group on a triathlon bike than on a road bike.

As with any set of generalizations, there are exceptions. Which specific bike is best for you, your riding style, your body dimensions, etc. is a function of many different factors. It is important to develop an idea of what your riding habits will be like and combine that with an accurate bike fitting from a bike fitter who has experience and training in fitting both road and triathlon bikes. That information will make deciding between a road bike and a triathlon bike easy.

© Tom Demerly, Bikesport Inc.
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