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Correcting positioning yourself on your bike is extremely important. If your
position is not correct, you will be uncomfortable and waste valuable energy.
Unfortunately there are many conflicting theories and opinions on the correct or
optimal bike position. I believe many factors need to be considered in obtaining
a good bike position, and it is as much an art as it is a science. Bike position
is also somewhat of a compromise between:
Thus, there is no
'one correct setup'. In fact each person may require a different bike setup for
different situations. An important point to note before contemplating changing
your position, is that your body adapts to a certain position. If you have
trained in the same position for 10 years, changing your position is not going
to take time to adapt to, as your body should have adapted to the current
position quite well - not matter how bad it is! Pedal and cleat position.
This is where you need to start with you bike setup. Traditionally the ball
of the foot should be directly over the pedal axle. I think this is generally
still valid for pure cycling, but I think the axle should be a little further
back for triathlon and in a time trial situation. The main reason for this, is
that having your cleat further back places a lot less strain on the calf muscle
- which is very good if you need to run after you have biked! If you have calf
problems, consider moving your cleats further back. This position also gives a
slight lever advantage (as do longer cranks).
The other consideration at shoe-pedal interface is the angle of the cleat. I
believe the cleat should be placed on an angle that is neutral for the rider.
This is even true for floating pedal systems, as not all float is resistance
free. Some maybe slightly pigeon toed, or slightly duck footed, depending on
their biomechanics. Although be wary of a setup that has both feet pointing the
same way - you are probably riding at a different angle to your bike!
Seat height.
This is very difficult to get right - but it is also very important. Minor
differences in seat height can dramatically alter power output and comfort. Sore
knees, quadriceps, and lower back may all be the result of incorrect seat
height. There are a few formula for calculating seat height, all of which may
give a different answer! Rumor has it that Eddie Mercx carried an allen key with
him in the tour de France, and changed his seat height during stages.
Tips that the seat is too high:
Pedaling with pointed toes (see figure 1). Hips rocking from side to side or lower spine is not straight while pedaling (figure 2).
Seat too low may result in:
Formula to calculate seat height: 1. Multiply leg length by 0.98. Leg length
is measured from the sole of the foot to the top of the ball on the femur that
connects into the hip joint. Add to the resulting measurement the pedal, cleat
and shoe thickness, and the result is taken from the saddle (mid point) to the
pedal at the bottom of the pedal stroke. 2. An older method using the inside leg
length, sets the pedal to top of the saddle height at 109% of your inside leg
length. Thus you multiply your inside leg length by 1.09. 3. Guimard, who
coached Greg Lemond, came up with the formula of multiplying the inside leg
length by 0.883. The result is a measure from the dip in the saddle to the
center of the bottom bracket, and is for 170mm cranks and "medium cleats
and cycle shoes. Thus if you have thick soles on your shoes, or quite high
cleats, you will need to add a little. Conversely you will need to lower your
seat for longer cranks. 4. My preferred method is to see a slight bend in the
knee at the bottom of the pedal stroke (approximately 30 degrees off straight),
while ensuring the toes are not pointed, and the hips are level (see figure 3).
Not very scientific I am afraid! Seat fore-aft position.
Traditionally this is determined by dropping a string from behind the kneecap
with the pedal placed at 3 o'clock. The string should pass through the pedal
axle (Those with longer femurs should have their seats further back). This is a
good starting point, but maybe thrown out the window in some setups that use
quite a forward position. This is where compromise may play a significant role.
As you bring your seat forward, you must also raise the seat height.
Other factors to be considered include:
Bike handling. Your seat position
will affect your weight distribution on the bike. With your seat along way
forward, you may end up with far more weight on the front wheel, making for more
difficult handling. Many other factors come into play here as well, including
frame geometry and handlebar setup. On a technical course, it maybe better to
have the seat a little further back, for better handling. -
Hill climbing. In
general a forward position is better on the flat, and not so good on the hills.
If you are racing on a predominately flat courses, a more forward seat position
maybe better (and visa versa for hilly courses). Of course you need to train in
the position you are going to race in! Seats with a long 'nose' can provide the
best of both worlds (if they are comfortable!).
-
Comfort, aerodynamics and your
body. Your bike set up will depend on whether you wish to optimize aerodynamics,
power output, or comfort, and on some of your bodies limitations (such as
flexibility).
Handle bar position.
This is where it gets very tricky. Where and how you position your handlebars
(and to some extent your seat for-aft position) will depend on your bike set up
objectives. As I mentioned previously, bike position is a compromise between
aerodynamics, power output, and comfort. Lets examine these.
The aerodynamic position.
When you are cycling above 32kph, most of your energy goes into overcoming
wind resistance. By far the biggest contributor to wind resistance is the body.
If you reduce wind resistance, then you go faster, or have to produce less power
to go the same speed.
Many of the top cycling teams are spending a lot of time in wind-tunnels, to
determine optimal bike setups for time trials. While this is not available to
most of us, there are a few 'rough' alternatives. One that Matt Brick (and
myself) used, is testing different positions on a down hill (preferably
reasonably straight). Starting at the same speed at the top of the hill, free
wheel down the hill in different positions. The better aerodynamic positions
will obtain higher speeds. You need to conduct this test under similar
conditions, and riding back up the hill several times can be a challenge in
itself! For me, a low tuck on the drops was quite a bit faster than using
aerobars (but difficult to ride in that position for a long duration)
General rules for reducing wind resistance: q Minimise frontal area: This
means getting as low and narrow as you can. Handle bar position plays the
biggest part in this. You need your handlebars to be low, and your aerobars
setup quite narrow. Without getting into the wind tunnel, I think a general
guide line is to have your hands as close together and possible, and your elbow
in a position that allows the air to flow smoothly around the rest of your body
(next 2 points).
-
Minimize turbulence: Reducing wind resistance is about
minimizing air turbulence. The less you disturb the air flow, the lower the
resistance. There are a few different theories about this, and it is not always
clear what works. Keep in mind that you want the air flow to be smooth, and you
want to disturb the air as little as possible.
-
Minimize air pockets:
Minimizing air pockets is really about minimizing turbulence. Aerobars overcame
a major air-pocket that is present with traditional drops - that is the air the
goes into the torso and is trapped by the head and arms. It is also possible to
minimize this with a flat back and quite a stretched out position on ordinary
drop handlebars.
The power position.
One of the first problems with a very low position (when
trying to minimize frontal area) is that it can reduce power output quite
significantly. The powerful Glut muscles are often at a very acute angle, and
unable to activate as well as in a more upright position. Breathing can also be
hindered, as the chest and abdomen are somewhat restricted in a very 'crouched
over' position. Miguel Indurain had difficultly obtaining a good aero dynamic
position for his one hour record attempts (he was quite high, in part due to
using very long cranks), but he could certainly produce a lot of power.
Some now advocate a less extreme areo position, with a more rounded back to
allow greater power output. This position opens up the hip angle and also can
improve breathing with the chest and abdomen encountering far less restriction.
An advantage with this type of position is that it is also far more comfortable,
particularly for those who are not so flexible.
Seeking more comfort.
Staying low and narrow can also be very uncomfortable.
Having an awesome aerodynamic position is not much use if you cannot maintain
that position for very long because it is too uncomfortable. The longer the race
you are planning on competing in, the more important comfort is. 180km in
Ironman is hard enough, without being very uncomfortable all the way. This alone
can be quite a challenge for some athletes. If you lack flexibility in the lower
back, and hamstring area, obtaining a comfortable position that is not
completely up-right can be a challenge.
If you suffer from a sore backside, lower back pain and/or a sore neck, it
maybe worth trying some of these strategies:
Get a comfortable seat. Make sure that what you are going to be sitting on
suits your body. No setup can solve a bad saddle problem. Many women have
problems with their saddles, trying a wider saddle can often help. Open the angle at the hip up (between your torso and legs). This can be
achieved through a combination of moving your seat forward, raising your
handlebars, and possibly shortening your stem length. Widen your aero-bar elbow pads. In general you want you aero bars to be in
a very comfortable position. Making you elbow pads wider apart will reduce
the strain on your neck and upper back. It may also pay to play around with
the angle of your aero-bars, to find the most comfortable position for your
riding style. Aerodynamically it maybe better to have them rising slightly.
However some people find it far more comfortable to have them level, or even
slightly lower (I don't think this is good though).
Other points to consider.
Here are a few other points to consider in your setup:
Your seat should be level. If it is not level, it will be uncomfortable
and there is probably something quite wrong with your setup. If you feel like you are always sliding forward, or backward on your seat,
then the seat probably needs to be moved forward (or backward). Crank length: You should get cranks that are appropriate for you height
and leg length. Longer cranks give a lever advantage (good for time trials),
but also lower cadence (not so good for accelerating). If your cranks are
too long, then you may end up with a dead spot (no power) at the top of you
pedal stroke, and you will not be able to get in as low a position. Your hand position on your handlebars should not be awkward. Where and how
you place your hands should be relaxed and quite natural. This can be
difficult for the smaller person, as the bike and handlebars maybe too big -
and obtaining the correct size can be difficult. As I mentioned at the start, changes in position do take time to adjust
to. However, sometimes changes just do not work! Don't be afraid to ask
different people for their opinion and most importantly why! If they cannot
explain why - then they may not know!
I hope that helps a little.
Tony.
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