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.
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Standard Road Geometry Bike
Triathlon Geometry Bike
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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.
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If this is how you ride, a triathlon bike is right for
you.
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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.
