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In Position to Win
Adjusting Your Position for Time Trials
In my "Get Fit!" article, I outlined the four crucial parameters
for bike fit: saddle height, saddle set back, handlebar reach, and handlebar
drop. In this article I want to take that one step further and talk about
how to use those same guidelines to dial in your time trial position,
either on your road bike or on a dedicated time trial bike.
When Boone Lennon first pioneered clip-on or "tri-bars" in the
late ‘80’s, his initial model and inspiration was downhill ski
racers: head low, back flat, arms together and pointed up in front. He
almost had it right. It was certainly an improvement, and evidenced most
convincingly by Greg Lemond’s barnstorming win in the final time
trial of the ’89 tour, but it was only the first step towards a real
understanding of the ideal aerodynamic position on the bicycle. What worked
for skiers was close, but didn’t translate perfectly to what would
work for cyclists. Over the next decade and many, many hours of wind tunnel
and wattage testing later, the "perfect" aero position is still
evolving, but has changed considerably, most notably in the position of
the arms.
How you approach your time trial position will depend on a number of things:
do you have a dedicated TT bike, or will you be modifying your normal
road bike? Will you be able to train in your TT position regularly? How
many TT’s will you do? Is it a focus, or is it something you’re
simply trying to make the best of? Whichever your approach, the way to
visualize changing your normal road position to a TT position is to view
it pivoting around your crank arms as the center point of a circle. If
you’re set up well in your road position, imagine rotating that exact
position forward with your feet in the same place: your saddle comes up
and forward, your back becomes more horizontal, and your head and arms
go forward and down. The question is just how far forward can you rotate
without compromising your pedaling power or setting up a position that
goes beyond the UCI rules, if that’s a concern for you.
There are two extremes you can take as your starting point. Let’s
assume you despise time trialing, and only do it when you have to as part
of a stage race. You don’t train for it, you don’t care about
it, and you certainly don’t have a separate bike set up to focus
on it. But you also hate losing all that time in the stage races every
time you have to do it. At the very least, you’d like to limit your
loses or do the best you can with the equipment you have. What can you
do to maximize your position with these parameters?
From this perspective, I’d be expecting to simply modify someone’s
position on their road bike, and would be looking to keep them in that
position as much as possible. That means there would be a minimum of forward
rotation. If for whatever reason you can’t or won’t be able
to train in the TT position, it’s never a benefit to go for some
extreme forward and low set up just for the day of the time trial. The
increased discomfort and inefficient pedaling dynamics will counteract
any increase in aerodynamic advantage.
At this extreme, I wouldn’t change a riders saddle height or set
back at all. I would leave the rear of the position in place, but then
see how much the front of the position can be made ideal with addition
of aero bars. With your road bars in their normal place and the addition
of clip-on bars, see how comfortable you are. Your goal is to get the
front end as narrow and low as you comfortably can, without changing the
way you sit on the saddle dramatically. Gradually lower your handlebars
to the limit of what your bike will allow. If you find your breathing
compromised or that your thighs begin to make contact with your abdomen,
then you’re at the limit of what you can do.
You might stop there, or you can start to change the rear of the position
to accommodate a lower front end. If you can train in this position and
have time to adapt, you can start slide the saddle forward and up to allow
yourself to go as low as your road bike will allow you up front. One low-cost
quick fix is to have a second seat and seatpost that you use just for
time trials. This way you can experiment with your TT position without
worrying about not being able to get back to your ideal road set up, and
you can switch back and forth quickly when you want to do a training session
or local TT. By the same token if you have a front-loading stem that is
quickly swappable, you might have a second stem that has some drop to
it and allows you to get lower, or is longer or shorter to change your
reach.
If you’re at the other end of the spectrum and time trialling is
a focus, then your approach will work the opposite way. Rather than basing
things around the rear of the bike and working forward, you can start
with the front and work back. How low does your TT bike let you get up
front? Start there, and see how high and how forward you have to set your
saddle position to let you ride comfortably in the bars. That doesn’t
mean you’ll end up in this position; you might find that there’s
too much weight on your front wheel and is unsafe, or that you loose too
much power and have removed your hamstrings from the pedaling equation
completely. The UCI rule for saddle set back is that the nose of the saddle
must be at least 5 cm behind the vertical plane of the bottom bracket
spindle. If you’re going to do any major races, then you know that’s
the limit of how far forward you can go. If not, you might go so extreme
as to have the nose in the same plane as the bottom bracket. That's really
the limit of what you should push. The key is to find a balance between
what’s aerodynamic and what’s biomechanically optimal.
Study photos of the top riders in their TT positions. Lance and Levi Leipheimer
as set up by aero expert John Cobb sit very upright with their arms ever
so slightly up, whereas someone like Chris Boardman was able to sit very
far forward and rotated down, so his head was almost lower than his hips,
and his arms were level or almost slightly pointing down. If you can sit
on a trainer in front of a mirror, you can tweak things and actually look
at how the changes affect your profile, then see if it’s a position
you can ride in comfortably or adapt to. If you have a way to measure
power, then you can experiment with different positions and see how it
effects your wattage at a set heart rate.
Remember that no amount of riding around easy in your TT position will
give you a feel for how it will be in a racing situation. The only true
test is to get out and ride it at the same effort you’ll make in
the race. Your goal here is to look for the balance between increased
aerodynamics as you can best estimate without a wind tunnel, versus a
minimal loss of pedaling power. For someone who rarely rides a TT, that
might mean staying in their basic road set up. For someone focusing on
the race against the clock, it might mean a dedicated bike rotated 5 or
more centimeters forward from their road position, and weekly training
sessions in that position.
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