THE
BASICS OF BIKE FIT
The steps to achieving a good bike fit are few and
easy. First, you must decide which style of
geometry is for you. Against the backdrop of some
immutable rules that apply to every position you
choose, you're free to ride however you want. You
can ride with a seat angle of 74 degrees or with
81 degrees. There is no necessarily perfect or
special, or even tri-specific geometry to which
you ought to aspire.
Each
of the three riders represented at right are in a
position that is appropriate for triathlon racing.
One immutable rule is that the range of motion in
which your thigh musculature operates ought to be
biomechancially sound. We might roughly refer to a
"hip angle" that is formed by using the
bony protrusion of your hip (greater trochanter)
as the apex, and with that angle's lines being: 1)
one that run from the hip to the foot, and, 2)
from the hip to the bony protrusion of the
collarbone.
That hip-to-the-foot line is a little tough to
nail down. Ought it to be from the hip to the
bottom bracket? Or to the maleolus (bony
protrusion of the ankle)? Or to the pedal axle? If
so, where? At the bottom of the pedal stroke? With
the crank in line with the seat angle (or relative
seat angle)? If it's the hip angle you're
measuring, why measure the angle in its most
obtuse configuration? Why not at its most acute,
when your foot is at the top of the pedal stroke?
All these are valid observations, but it doesn't
much matter. If the proper bike fit is in fact
proper, it doesn't matter where you measure, but
each of these lines formed by the proximal point
(hip) and the terminus at the line's distal point
(ankle, BB, pedal axle, whatever) is going to
change depending on which distal point you choose.
I personally favor the pedal axle at the bottom of
the pedal stroke, and my definition of
"bottom" (for the purposes of measuring
this angle) is not at 6 o'clock, but at the point
where the axle is in line with the seat angle.
The preferred angle is 90-95 degrees, and while I
don't like angles more acute than that, I don't
mind a more obtuse angle, up to a point. I can in
some cases live with 100 degrees. I have a problem
living with an angle greater than that. As long as
this is your hip angle, however, it doesn't
matter to me whether you're riding at 71 degrees
or 81 degrees of seat angle. Realize,
however, that as you rock yourself back in the
saddle you're rocking yourself up in front, that
is, your back will not be as flat and you will
probably be punching a larger hole in the wind as
you propel yourself forward.
Why would one want to be less aerodynamic?
Comfort, plain and simple. Rotating one's body
complex forward means you're no longer sitting on
that padded place God provided for you. You're now
resting on the saddle in places God did not intend
in his infinite wisdom for you to rest. Perhaps
the Grand Design did not contemplate triathlons.
When
one rocks all the way back—the Green
Rider—this is a road race position, and a proper
road bike fit is easy to achieve. By “road
bike” I’m talking about the Trek Lance
Armstrong rides on those days in France when the
whole pack starts together. No aero bars on that
bike.
If you’re a triathlete, however, you no doubt
feel compelled to have triathlon bars on your
bike. You shouldn't. Not necessarily, at least.
There is nothing wrong with riding—even while
racing in a triathlon—on a road race bike with
road bars, STI or Ergopower shifting, and no aero
bars whatsoever. In fact, if you're new to the
sport, that's probably the best choice you could
make, especially if you're brand new to STI-style
shifting and clipless pedals, and if you've never
before ridden with tri bars. All that is hard to
learn in one fell swoop.
Besides, in another month, or two, or six, you can
bring your bike into the shop and have aero bars
retrofitted onto this bike. This is easy, it's
just a pair of clip-ons, and it takes 5 minutes to
add them. If you add full aero bars, however, you
may find that that perfect road bike fit doesn’t
work anymore now that you’ve laid your body down
on the apparatus that essentially turns your bike
into a front recumbent.
The
keys to a good fit while on aero bars are few, and
easy to grasp. There is now a second angle with
which to be concerned, and as is the case with the
hip angle above, this second angle is not an angle
on a bike—but one formed by your body. Remember
that line running from your hip to your shoulder?
Now imagine a line from your shoulder to your
elbow. This “shoulder angle” formed between
your torso and upper arm also ought to be 90
degrees. Achieve this angle and you’ll be
comfortable.
(A NOTE ON MEASURING ANGLES: Finding the proper
point on your shoulder can make these angles tough
to measure, and the points differ depending upon
which angle I'm measuring. I find that when
measuring the hip angle the line ought to pass
from the greater trochanter through the shoulder,
and through the collarbone which, while in the
aero position, will be in front of the shoulder.
But when you're figuring your shoulder angle, the
line representing the upper arm ought to pass
through the centerline of the arm midway from
front to back. The intersection of these two lines
represents the apex of the shoulder angle being
measured.)
The problem with sticking full tri bars on your
“perfectly fit” road race bike is that the
bike is too long for these bars or, if you prefer,
the clip-ons are too long for the bike. You’ll
notice that your shoulder angle is greater than 90
degrees. You’re too stretched out. The solution?
Don’t get full aero bars. Buy a shorter bar made
just for a road bike position. There are several
out there. Cinelli makes two, the Spinaci and the
Corna. Profile Design makes a very popular model
called the Jammer, and a souped-up version called
the Jammer GT.
The good thing about these bars is that they’ll
allow you to achieve that 90-degree shoulder angle
without changing the fit and set-up on your road
bike. The negative is that the armrests aren’t
hitting you under your elbows, but under your
forearms, almost under your wrists. That is not
optimal for a lot of people.
Enter the “tri bike.” This is a bike built
around the proposition that you’re starting with
a full aero bar, and the geometry of the bike is
built around the use of the bar. This bike has a
very different geometry than a road race bike, but
the “rules” mentioned above still hold. How is
that so?
Imagine a picture of a hill climbing specialist
riding seated up Mont Ventoux. Stick a straight
pin in his bike’s bottom bracket, and rotate the
picture forward. His rider position won’t
change, if you’re considering the “body
angles” spoken of above. If you’re very good
with a pair of scissors, cut out just the rider,
separating him from his bike. Now rotate him
forward around the same axis, leaving his bike in
place (as in the photo below-left). You’ll
notice his trunk moves forward relative to the
bike’s bottom bracket. His back gets flatter.
He’s assuming an “aero position.” The only
thing we need to do is to place an aero bar
underneath his elbows. And this is what a tri bike
is—steeper seat angle, lower front end, and a
shorter chainstay so as to draw the rear wheel
back under the rider’s weight, so that the bike
handles appropriately.
How
much should you rotate this rider forward? It’s
up to you. You can ride with a 73-degree seat
angle, typical of a road race bike, more or less.
Or you can ride at 80 degrees, common in a
full-blown tri bike offering a very aero position.
Anywhere in between—anywhere along this
continuum—is fine. The steeper your seat angle,
the lower your bars can go, that is, the flatter
your back can be.
Realize, however, that there are equipment and
configurational changes that follow each move
along the "continuum." As you move back
in the saddle your aero bar armrests ought to be
raised higher, and will be closer in elevation to
the level of your saddle height. As you move more
forward, your armrests can be lower, and your back
flatter. If you decide to ride more in a
conventional (rearward) road race position, with
road bars and STI shifting, your aero bar's
extensions will be shorter, and your armrests will
"move up" your forearms toward your
wrists. The more forward you are, the lower you
will be, and at some point on the continuum (maybe
at around 77 degrees of relative seat angle)
you'll want to change from road bars to pursuit
bars and bar-end shifting, and then your arms will
rest on the armrests with the pads more under your
elbow than your wrists, and your aero bar
extensions will be closer to full length.
"Why can't I ride my road race bike in a road
position AND have full aero bars AND ride with the
armrests under my elbows?" you might ask. You
can. But then you're likely to have a shoulder
angle much greater than 90 degrees, and you'll be
uncomfortable. In other words, you can't have it
all, so you'll have to pick which features you
want, and which you'll choose to live without.
WHICH
GEOMETRY STYLE IS RIGHT FOR YOU?
In the beginning of my remarks I wrote, "You
must decide which style of geometry is for
you." How do you decide that? When a person
comes to me for a bike fit, I ask a variety of
questions, such as:
- Do
you have only one skinny-tired bike, or will
you own both a road race bike and a
tri-specific-geometry bike?
- Are
you intending to road race on this bike, or
commute, or do centuries and group rides with
road riders?
- Do
you intend to spend a lot of time in the aero
position, or only be there very occasionally?
- How
important is speed to you? (This is not a
rhetorical question, there are plenty of
people for whom the finish time is not
especially relevant).
I will also attempt
to ascertain how athletic this person is, and how
high the effort level is likely to be during the
bike leg of the race. I'll consider the person's
morphology—someone who is carrying a lot of
extra weight is going to have that weight coming
down on the saddle and whatever place on one's
anatomy is in contact with the saddle.
Something must be understood about a full-blown
aero position. It is most comfortably ridden while
under a fair amount of power and effort. Riding an
exceptionally easy (perhaps recovery) ride is less
pleasing in the aero position than on a road race
bike. The easy solution is to have two bikes,
which I do. But not everybody does, or at least
they don't while still new to the sport. But that
does not lessen the realities of which position is
best for which style of riding.
Having an an aggressive, aero position for riding
to Starbucks for coffee is like commuting to work
in the city using a Ferrari. Sports cars are nice,
but a Caddy is perhaps better for stop-and-go
traffic. How often, and for how long at a stretch,
will you be riding with effort in the aero
position? That answer to that question will
determine where along the continuum from shallow
to steep you ought to be.
For this reason, I usually recommend a road race
bike as one's first entre into tri-bike ownership.
This bike is easy to ride, and the position is
accessible to just about anyone. It's a better
bike on which to learn click-shifting, clipless
pedals, and the beginnings of riding in the aero
position. It's a better bike for corning and
descending. It may end up being the only style of
bike you'll ever own for triathlon. And if you do
migrate to a tri-specific bike, you'll still use
your road bike for group rides, recovery rides,
early season riding, and so forth.
Having
said that, there is one other option. Consider the
"pink" rider at right. That might be
what we could term a "multisport"
position, and is just a bit of the way forward in
the continuum. One could achieve that position by
retrofitting a road bike with short aero bars and
moving a few centimeters forward, or by having a
slacker-than-usual tri-specific bike. For that
person who is looking to spend not too much money
and who wants a bike built just for the "multisport"
position, however, this category of multisport
bike is gaining in popularity, and the Cervelo
One, at just under $1000, is probably the best of
the current lot.
The one thing to remember is that shallower-angled
road and "multisport" bikes are best
ridden with road bars and road-style shifters and
brake levers. Choose a handlebar set-up which is
appropriate for that point along the aero
continuum with which you’re comfortable. Will
you be riding in a road race position, at 72 to 75
degrees of seat angle? Choose road race (drop)
bars with STI-style shifting and clip-ons. Are you
going to be on a steep seat angled rocket? Choose
pursuit bars and bar-end shifting.
WHY
MUST SEAT ANGLES MATCH FRONT END CONFIGS?
I'm not very patient with bicycle manufacturing
companies. They ought to know how to build bikes
correctly, and you'd think that if they were going
to spend a million dollars or more on a line of
bikes for triathletes, they'd take the time to get
it right. Unfortunately, it's common to have no
one in these companies who actually ride tri
bikes; neither do these companies' product
managers seek valuable information or guidance
during the design the process. If anything, they
ask their dealers what they want. This is often
the blind leading the blind.
As a result of a process like this, in recent
years you've had Cannondale making a tri-geometry
bike outfitted with road bars and shorty clip-ons
(a no-no) and Giant making a road geometry bike
outfitted with pursuit bars, full clip-ons and
bar-end shifting. In point of fact, both these
companies made one frame, and outfitted their
cheap model with road bars, STI and shorty clip-ons,
and outfitted the expensive model with the full
tri set up. The difference between these
companies' approaches is that C'dale chose a steep
seat angled tri geometry for the frame behind both
these front ends, and Giant chose a road geometry
frame.
In the case of C'dale, the proper bike was its
expensive model. Since this frame was a full tri
geometry frame (78-degrees of seat angle), it
ought to ONLY have been outfitted with
pursuit/full clip-on/bar-end shifting. It never
should've put road bars and a shorty clip-on on
this frame (which is what it did with its
entry-level model). Thankfully, this sort of mis-spec
is in Cannondale's past and it now makes its tri
bikes with quite a bit of forethought.
Giant's situation is current, and its approach is
the opposite. Its cheaper bike, the TCR Aero II,
is a road bike outfitted with road race bars/STI
shifting/shorty clip-on. That's a front end that
matches the bike's geometry. It's a good bike. But
its expensive bike is the TCR Aero I, and it's got
a full tri front end. I don't agree with this sort
of spec. Happily, it's more or less fixable.
Outfit this bike with a forward seat post or an
M2Racer Power Module and the bike becomes more
usable.
Let's say you were sitting at the dinner table and
you were served a hot dog, a baked potato, mustard
and sour cream. Those of you who'd put mustard in
the baked potato and dip your hot dog into the
sour cream ought to put a pursuit bar on your road
race bike. For the rest of you, the moral of the
story is this: There is nothing wrong with shallow
angles, steep angles, road bars with STI, or
pursuit bars with bar-end shifting; just make sure
you put a front-end on your bike that is
compatible with the style of bike you're riding.
The simple way to view it is this: If you're going
to ride a traditional geometry, ride the bars that
traditionally go with it (road race bars). You
contact the bike in three places—where the bike
meets your hands, your butt, and your pedals.
These three places must be properly spatially
related to each other, and they must allow the
body to form the two 90-degree angles mentioned in
the sections above.
There is a reason that full tri bars don't make
sense on a shallow-angled tri bike, and it is
related to your shoulder angle. When you're on a
properly-fit road bike, and you're riding in a
road configuration—73 degrees of seat angle,
road bars, STI, etc.—and when your hands are on
the hoods, you have something close to that magic
90-degree angle (when you're low and really going
hard, with your forearms parallel to the ground).
When you put a full tri bar on your bike, the
clip-on's extensions reach considerably further
forward than the forward protrusion of the hoods.
If you extend all the way, and your hands grab the
extensions' ends, your shoulder angle is much
greater than 90 degrees. You're too stretched out.
In order to achieve that 90-degree angle, you'll
have to have a shorter clip-on—either a very
short size of a full clip-on, or a model of "shorty"
clip-on with shorter extensions by design.
Of course you could also achieve that 90-degree
shoulder angle by moving your saddle forward
instead of by moving the clip-on extensions back.
Nothing wrong with this, except as you keep moving
forward you've got more and more weight on the
front wheel, and this can cause handling problems
(hence the tri bike). Forgetting that for a
moment, your saddle's movement forward also allows
your aero bars to move lower in elevation, that
is, you're allowed to make yourself more
aerodynamic. Now you've got quite a different
position. Your saddle is forward in relation to
the bottom bracket, and your road bar's hoods and
drops positions are now much closer to you, and
they're sitting much lower than the saddle. Your
"points in space" are very different in
relation to the saddle and to the bottom bracket.
They don't work anymore.
Enter the pursuit bar. The idea is to re-create
the position formerly inhabited by your hoods,
i.e., before you lowered your road race bars to
make yourself more aerodynamic. The irony is,
people are fain to give up their road bars because
they covet their hoods position. But when you
lower your bars, you may keep your hoods, but you
lose your favored hoods position (and you entirely
lose your drops position). The only way to
maintain your hoods position is to dump the
hoods, and the bars on which they're mounted, and
go to a flat pursuit bar. Then you'll regain
(something close to) your hoods position.
I'm often asked about the utility of having STI
shifters on a pursuit bar. I don't like this,
because of the technical way a forward tri
position ought to be ridden. I'll write about this
in more detail in a future installment, but for
now I'll reiterate that this is a position which
must be ridden at a high cadence—no lagging, or
mashing. The need to shift often is paramount, and
having the shifters where your hands are is
critical.
SADDLE
HEIGHT
There are three ways to determine saddle height.
Method Three is the subjective method—adjust it
until it feels right. This is really the ultimate
eventual way. After you utilize objective methods
One and Two, you'll always come 'round to Method
Three. But you shouldn't start there and besides,
your ability to correctly apply Method Three
depends upon whether you're body aware and
untuitive, and some people are just body-deaf (or
whatever the body-awareness-analog is to
"tone-deaf").
This leads us back to the objective methods.
Method One is to use a multiplier of one's inseam.
Stand on the ground, straight-legged, and place a
book up into your crotch, about where you figure
the saddle will rest. measure this distance to the
ground. Multiply this by .885. Some people use
.883. Personally, I don't like this method,
because of the imprecision of where the crotch
actually is; and where to measure to on the
saddle's top. I also think that for steep
seat-angled tri bike riding the saddle ought to be
slightly higher than for road riding. This
remains, however, the predominant way to measure
saddle height.
Method
Two is to consider the knee angle when the pedal
is in its lowest position. But first there are a
few things I need to make clear. There are two
places on the foot to which you're going to
measure. When you're determining the location of
the bottom of the pedal stroke, this is
measured to the pedal axle, and while the
differences are minute, and for the purposes of
measuring knee angle, I don't like to consider 6
O'Clock the bottom of the pedal stroke. I rather
prefer it to be that point where the crank arm is
parallel to the line drawn up to the greater
trochanter (i.e., more or less parallel to the
seat post). If you consider the red line in the
adjacent diagram, this is the position in which
the knee angle ought to be measured.
But once your leg is in this extended position,
you'll now start measuring to a different area.
When determining knee angle you're measuring to
the maleolus.
Using the bony protrusion of the outside of the
knee as the angle's apex, draw a line to the
greater trochanter (bony protrusion of the hip)
and to the maleolus (bony protrusion of the
ankle). The angle formed ought to be either
145-150 degrees, or 150-155 degrees, depending on
whom you talk to. For road riding, I think 150
degrees sounds pretty good. For tri bike riding I
like it closer to 153-155 degrees. Perhaps
increasing the angle one degree might be roughly
equivalent to increasing the saddle height by one
millimeter, though it's going to differ depending
on the height of the rider.
The tricky parts of calculating saddle height by
Method Two are: 1) you really need a second person
to do this; and 2) your pedaling technique is
going to effect this—if the aspect of your ankle
is not correct during the pedal stroke it can
cause your seat height measure to be off. If, for
example, you're pedaling too much with a
"toes down" aspect—if you have to
stretch to reach your pedals—you might think
your seat height is correct by virtue of your knee
ankle when in actuality your seat would be too
high.
On the other hand, the nice thing about this
method is that it takes into consideration the
height of your cycling shoe, pedal and cleat,
where you sit on the saddle, any shims that
correct for leg length discrepancy, and your crank
length. It also takes into consideration any
influence exerted by your pedaling technique. So I
guess I like this method better.
What do I mean by "influence exerted by your
pedaling technique?" I tend to ride with a
fair amount of "heel drop." I also seem
to read that heel drop, or lack thereof, is a
matter of personal preference. Fair enough. But
whatever your preference, it's going to make a
difference in your saddle height. If my heel is
dropped more than yours at the bottom of the pedal
stroke my saddle needs to be slightly lower in
order to maintain this 150-155 degree knee bend.
What influences heel drop? Your power application
throughout the pedal stroke, your desire to
utilize your calf muscles—a somewhat
insignificant muscle group in pedaling, but of
some utility—and your cleat mount (the more
forward your cleat, the more you can recruit your
calf muscles).
DETERMINING
WHICH POSITION IS BEST
Now we get to the meat of it. This is the most
difficult part, and if you're a bike fitter it's
the part requiring the most skill, in my view. I
don't mean the act of executing a proper tri bike
fit on, say, Tim DeBoom or Peter Reid. That's
easy. That takes 20 minutes, or ought to. The
skill comes in determining whether a subject ought
to be positioned like Peter Reid, or on a road
race bike with STI and shorty clip-ons, or
somewhere in the middle. And if it's in the
middle, where in the middle?
The hard part is figuring out just how aggressive
one's position ought to be and can be. The devil
of it is, you can be positioned at 74 degrees of
seat angle, 76 degrees, 78 degrees, and at 80
degrees, and in each of those positions you might
feel great. If you are positioned too shallow,
might you've gone faster if you were positioned
more steeply? If you're set up steeply, what will
you feel like after three hours in the saddle? I
believe the art and science of tri bike fitting
ought to be light on the art and heavy on the
science—but if there's a place for art, this is
it.
The goal is to get you as close to 80 degrees of
seat angle as possible. The reasons for this are
two. There is the lower metabolic cost associated
with riding further forward, as demonstrated by
those in the scientific community. By "lower
metabilic cost" I mean less recruitment of
fast twitch fibers during the pedal stroke,
leading to a lower rate of glycogen consumption at
a given power output (fast twitch fibers consume
glycogen at a rate 50 percent greater than do slow
twitch fibers). I admit that it takes a short leap
to come to the conclusion at which I've
arrived—a tieing together of studies to make a
point. My full explanation will be found by
following the link above.
Then there is the aerodynamic benefit associated
with being able to ride lower in front, which is
linked with riding forward (it's hard to ride low
if you don't move forward). This requires another
leap of faith. It's my assumption that by having
one's handlebars lower rather than higher that the
result will be a position exhibiting better
aerodynamics. Surprisingly, even this is not
universally agreed upon. But we'll assume this as
axiomatic, and for those who don't believe that
lower in front almost always means a lower
coefficient of drag, we'll just have to agree to
disagree.
Though a lower front end might mean lower drag, it
doesn't necessarily mean a lower finish time.
There are four mitigators, and each of these
mitigators serves to cause one to sit further back
than 80 degrees. The major one is comfort. If you
can't maintain the position comfortably for the
duration of your race, what good is it? In this
case it's better to be more rearward. This will
mean you'll also be a little higher in front.
You'll sacrifice a little bit of aerodynamics. So
be it. You'll be better off in the long run (pun
intended).
The second mitigator is the "M-factor"
and "M" is for Mystery. Yes, Peter Reid,
Cameron Brown and Tim DeBoom ride quite steeply.
But Cameron Widoff doesn't. Yes, Craig Walton
rides steeply—very steep, if you consider not
just his bike set up, but where he rides on top of
the saddle—yet his countryman Chris McCormack
doesn't. Natascha Badmann and Paula Newby-Fraser
ride steeply, but Heather Gollnick doesn't. While
three-fourths of the world's best triathletes ride
steeply, 20-25 percent don't. Why? Is it because
they don't know any better, or because they just
haven't been set up in a correct steep position?
I don't think this gives them enough credit. I
rather suspect it has something to do with levers
and musculature. I don't believe riding with a
steeper seat angle gives you more power at the
same heart rate (a claim I've seen), but I do
believe it gives you equivalent power and heart
rates while spreading the work around to both
anterior and posterior thigh musculature during
the pedal stroke. Let me use an analogy...
Imagine a company with too few workers and a lot
of work to perform. Some of their employees have
to work overtime, and the company must pay
time-and-a-half. If they hire a few more
employees, the work gets spread around, and the
company doesn't have to pay overtime. Let's say,
however, that it's the best, strongest workers
who're getting overtime pay. Do you hire more
workers or pay overtime to the strongest workers
you've got? This is the dilemma. Most triathletes
find that more employees is the better solution,
and as a result everyone on the job has more
energy for happy hour after the evening whistle
("happy hour" being the "run"
in my metaphor). For some athletes, though, I
think evening the work throughout the thigh
muscles isn't playing to their strengths. I don't
entirely know why.
The third and fourth mitigators have nothing to do
with anyone reading this, but I'll mention them
anyway, because the subject comes up. There are
two reasons Lance Armstrong doesn't ride with a
steep seat angle. The first one is, he'll get
kicked out of the Tour de France if he does. The
rules won't allow it. If your racing was governed
by these rules, believe me, you would know it.
Only bike racers fall under these rules, and even
then not one percent of the bike races in the U.S.
are subject to UCI rules. But even if the rules
did allow Lance to ride more forward in the time
trial, I don't know that he would. There is a risk
associated with changing one's riding style for
one or two days sandwiched in between the 20-odd
days of a grand tour. I suspect that's a risk some
grand tour riders are unwilling to take. Keep two
other things in mind when using Lance's riding
position as a model. First, he's not running off
the bike. Second, in his "former life"
he did win two national triathlon championships on
bikes I provided him—both 80-degree seat angled
bikes.
Contemplate the diagrams above, and realize that
anywhere along the continuum from 74 degrees to 82
degrees of seat angle are fine. However, there are
rules you must obey. First, those two 90-degree
angles written of above must be preserved. Second,
the more rearward you are the more appropriate are
road bars, STI, and a shorter clip-on. The more
forward you are, the more pursuit bars and bar-end
shifting start to make sense.
Where ought you to be along this continuum? All
things equal, the younger, leaner, fitter and
lither you are, the more forward you'll want to
ride. Also, the shorter the race the more you'll
probably want to be forward. If you ride with
lesser effort, if you carry more weight, if you're
older, if you race a longer distance, and if
you're more of a mesomorph (strong, muscly-type)
the more you're likely to tend toward a position
back from 80 degrees.
Where you eventually ought to end up depends on
your subconscious tendencies while riding. Do you
always seem to be scooting forward in the saddle?
Are you sure it isn't because you're too stretched
out, and you're subconsciously trying to
"achieve" that 90-degree angle between
your upper arm and torso? If you're riding on the
saddle's nose in spite of having a proper cockpit
distance, you're probably positioned too shallow.
Are you always pushing yourself back in the
saddle? Are you sure it's not because your
saddle's nose is tilting down (a bad idea, by the
way), causing you to have to push yourself back
because you're sliding forward? If you're almost
always sitting on the rear of a level
saddle, perhaps you're too far forward. Are you
frequently out of the aero position? Again, you're
probably too low in front and too far
forward—while it's a position that might feel
good for short spurts, if you can't maintain it
for the duration of the ride, you're just too
aggressively set up.
A
NEW FORMULA FOR SLACKER-ANGLED ARMREST DROP?
I have a formula for armrest drop, and it is this:
This formula causes
a lot of hand wringing, because people just read
it and try to conform to it, without following the
"rules" that are associated with it. But
first, I'll explain it.
Distance "C" is what we're looking for,
and it is the distance in height (in a vertical
plane) between the saddle and the armrests. If you
were to drop a line from the top of the saddle to
the ground, and measure it, and then do the same
with the armrests, the difference between these
two numbers would be the difference in height
between the saddle and the armrests. The easiest
way to measure it, I think, is to lay one end of a
carpenter's level on the saddle, and angle the
level over one of the armrests. With the bubble in
the middle of the level (i.e., with the level
parallel to the ground), measure from the bottom
of the level to the top of the armrest with a
ruler.

The assumption is
that we've already got the seat height
established, via the guidelines in a chapter
above. We've also got the "cockpit
distance" more or less established, that is,
the distance from the nose of the saddle to the
ends of the clip-ons, because that distance is
whatever it needs to be in order for our upper arm
and torso to achieve a 90-degree angle. You've
then raised/lowered your bars so that your
"hip angle" achieves a 90-degree angle,
or perhaps 95-degrees, and by virtue of that we
don't really even need a formula for armrest drop,
because the drop is whatever it needs to be in
order to achieve the proper hip angle, right? So,
why do we even have a formula for armrest drop?
Only as a
double-check. If, after you've positioned
yourself properly, you plug your saddle height
into the formula and you get a number WAY off
from the range indicated by the formula, then
you've got to ask yourself why. Perhaps there is
a perfectly appropriate answer. Either way,
that's what the formula's for—it's just a
double-check.
But there are rules and assumptions:
• This formula
assumes that you're a very fit, well-trained
athlete in mid-season form.
• This formula applies to a position all the
way forward along the continuum, which for me
means something in the order of 80 degrees of
relative seat angle. If you're positioned at 76
degrees and you try to apply the formula above,
you might find that the position is too
aggressive and—guess what?—you'd be right.
You don't have a steep enough angle to justify a
drop of that degree.
Here's how it would
work, and I'll use myself as an example—I'll
present the formula again below for reference.

I ride with about
79cm of seat height (distance "D" in the
formula above). That quantity, squared, times
.005, equals 31.2. Subtract 79 X .2 (which totals
15.8) and you get 15.4. Subtract 1.5 and that
equals 13.9 (we'll call it 14)—and realize all
these calcs are in cms. The fudge factor is 1.5cm
in either direction, so my armrest drop could
range anywhere from 12.5cm to 15.5cm. It is in
fact about 13.5cm.
I admit, however, to having a more aggressive seat
angle than most (I ride with 80°). What about
those who'd like to ride at perhaps 78°, or 76°?
What ought their drop be? While I'm not convinced
of the utility of this, I'm working with a
coefficient-based adaptation of the formula above,
where ".2" above increases by 075 for
each degree shallower than 80° you'd ride. So, if
you rode at 79° the product would be (.2075D),
and if you rode at 78° it would be (.215D).
Here's the calc for someone riding at 77°:

In this case, if I
were to use myself as an example (and if I haven't
made a mistake) the drop for me at 77° of seat
angle would be about 12cm, and the range would
then be 10.5cm to 13.5cm. In other words, if I
slackened my seat angle by 3°, I'd probably have
to raise my bars about 2cm, more or less. You can
see why this would be the case. If I don't
raise my bars when I slacken my seat angle, my hip
angle will become too acute.
Perhaps adding this whistle to my formula will
prove efficacious, though it's too early to tell.
I hope, at least, that you see the point, which is
that you can't take any of these features—seat
angle, armrest drop, clip-on length, base bar
type—and consider them in a vacuum. They all
must make sense as a construct. I hear, every now
and then from retailers, that my formula
represents a front-end drop that is too low for
the bulk of their customers. Maybe it's because
the rest of the fit is bad. Or maybe it's because
it's being applied to customers who're being set
up at 76 degrees of seat angle. If one takes into
consideration the limitations of this formula in
its raw form, then perhaps it appears less
formidable.
HOW
TRI-SPECIFIC GEOMETRIES MUST BE RIDDEN
This topic is not specific to tri bike fit,
strictly speaking, but it deserves mention. If
your retailer sent you and your mate out the door
on a tandem, he'd be well advised to give you a
tip or two if you were tandem virgins. Likewise,
it ought to be pointed out that your riding
experience on a tri-specific bike is not going to
be 100 percent positive if you don't take
advantage of the strengths of this bike.
By "this bike" realize what I'm going to
present below assumes that you're on a
tri-geometry bike, riding with a seat angle of 77
degrees to 81 degrees. The shallower you are—76,
75, 74-degrees—the less this section refers to
you. In fact, if you're riding below 75 degrees of
seat angle it doesn't refer to you at all.
There are just three things to remember, and these
points ought to govern your tri-geometry riding.
• This is a position which optimizes the use
of lay-down, tri-specific handlebars. Any time
you're in the aero position, you're on a better
bike than a road race bike. Whenever you're out of
this position, you'd have been better off on a
road race bike. Therefore, you better like your
position, and be prepared to be in it almost all
the time.
Imagine skating around an ice rink. What is your
intent? To skate quickly, and perhaps race? A
nice, long pair of speed skates is made for the
purpose. But what if you want to just knock around
with the guys occasionally? Jump into a hockey
game now and then? Do a few pirouettes? Or just
tool around at an easy clip? Clack skates aren't
made for that purpose, and you'll find them
unwieldy. Likewise, a steep tri-geometry bike
isn't made for much else other than going hard at
it while in the aero position. Consider this
before you adopt this position.
Because of this, there are certain positions that
make sense and others that don't. Besides being in
the aero position, there is also an intermediate
position that I sometimes adopt, something not
unlike the "multisport" position
described above. I call it a "choke up"
position, and it's adopted by moving very slightly
rearward on the saddle, choking up a few inches on
the extensions, and sitting slightly up. While in
this position you'll be able to generate a bit
more peak power, and you might benefit from
getting out of the full aero position now and
then.
Riding entirely out of the saddle is also a usable
position, and riding in the pursuit position is
fine for descending and cornering. What I often
see, but do not at all like, is a sitting-up
position with the hands on the armrest pads while
seated climbing. The hip angle is now too obtuse,
and this is a low-cadence, low-power position.
Better to climb either in the aero position,
perhaps in the choke-up position, or out of the
saddle. Never sitting entirely up.
• This style of riding trades high-torque
riding for even-powered riding. You won't be
able to generate the sort of peak torque in the
aero position that you will while in the road
position. Your overall power will be the same, but
your ability to mash a low cadence, or to
accelerate, will be compromised. Therefore, it is
imperitive to keep one's cadence up, probably in
the 90-100rpm range. It's quite acceptable to
climb while in the aero position. You'll be
surprised how fast you can climb, although you
might not think you're climbing fast unless you're
comparing yourself to others of equivalent
ability, or your own previous times recorded up a
fixed ascent. But you will be able to climb
fast. This assumes, though, that you really do
keep your cadence up, and this is a discipline
that is hard to learn.
If you think about this, a couple of equipment
changes appear rational. First, if it's so
important to keep your cadence up, it's important
to keep your shifters close to your hands.
Therefore, bar-end shifting is a very good idea
for steep-geometry riding. Secondly, make sure
you've got the appropriate gears at your disposal.
I'm usually riding 53X39 and 12-27 on my
700c-wheeled bike. On a hilly course I've been in
my 39-27, spinning up a hill in the aero position,
next to a person climbing out of the saddle in his
big chain ring. If that gentleman outruns me it
won't be because he was a wiser tactical rider.
"Why?" you might ask, "is it
preferable to trade in a high-torque position
(riding a 73-degree seat angle bike) for a
low-torque position?" Because you don't want
to recruit fast-twitch fibers during the bike
ride. You don't want to use muscles that burn
glycogen at a higher rate. This issue is what
separates road riders from triathletes. This is
why triathlon is its own sport, and why you can't
necessarily emulate what you see in the grand
tours, even the grand tour time trials. If you
don't have to run off the bike you don't have to
worry about the metabolic cost of your bike ride.
If you're reading this, it's likely that running
is in your future.
• This position is most comfortably ridden
under effort. The more you're rotated forward
and low in front, the more you're riding on points
on your trunk that don't have much padding. When
you're riding in this position under very low
effort, the weight is transfered off the pedals
and onto the saddle. Therefore—though it sounds
counter-intuitive—the lesser your effort level
while in the aero position, the less comfortable
your crotch. This doesn't mean you can't ride your
tri bike during easy, recovery rides. It just
means it's not optimized for that. If you have a
road race bike, this is usually a better choice
for recovery riding.
Don't take this to mean that a steep-geometry
position is unusable for all kinds of riding. It's
usable, just not optimal, for all kinds of riding.
Likewise, road bikes aren't optimal for all kinds
of riding, but they're often used in triathlons
anyway. It's just a question of what sort of
riding is most important to you, and then adopting
not only the most appropriate bike position, but
the tactical and technical riding styles that
dovetail with that position. When I hear, "I
tried a steep-angled bike but I found I just
couldn't generate enough power," I find that
in most cases it was because the rider didn't
understand how steep geometry bikes need to be
ridden. He rode his tri bike around town at
70rpms. Of course he couldn't generate enough
power.
HOW
DO YOU CHOOSE A BIKE AND HANDLEBARS?
If you were in the market for bike for road
racing, things would be simpler. Most road bikes
are built inside fairly narrow parameters. There
is almost no road bike in your size that you can't
easily make fit.
Not so in triathlon, where a wide variety of
options exist. There are "tri bikes"
with 74-degree seat angles, and with 80-degree
angles. At 6'2" in height a tri bike in
"my size" might have a 60cm top tube or
a 54cm top tube. Certain bikes styled as tri bikes
are in fact nothing more than road bikes marketed
to triathletes. How does one go about choosing?
There are some guidelines that might help.
You can make any bike fit. I'm reminded of an
Arnold Swarzenneger movie in which he had to rip
out the seat of a small car he was
"borrowing" in order to fit inside it.
Better if he just had to adjust the seat back a
bit. The trick is to find the bike that takes the
least amount of jury-rigging to make fit.
Your first duty is to figure out which position is
going to work for you—where along the continuum
(spoken above) you'll need to be. There's nothing
wrong with being all the way back, i.e., to ride
in a road race position. You'll have a difficult
time riding comfortably with a full tri bar,
however. Better to get a shortie bar.
At this point I shall digress slightly, and gently
scold many of you who'll read this. As I write
this I'm fresh back from the Wildflower Triathlon,
where I had the opportunity to ride past perhaps a
couple of hundred athletes. These are good
athletes. You don't enter the half-Ironman version
of this race unless you're reasonably fit. There
were four things I noticed: that a great number
were on traditional road bikes in a road
configuration; that the overwhelming majority were
riding with road bars and clip-ons; that most had
full tri bars (not shorty bars); and that a good
half of all the riders were out of the aero
position and on their hoods, even though riding on
the flat roads.
The greatest number of athletes I encountered were
riding on the "backstretch" of this
course, the straight section from mile-20 to
mile-35. This entire stretch was ridden into a
headwind. There was every reason to be in the aero
position and no reason not to be. Why were so many
riders not where they ought to have been?
My view is that after 30 or so miles of hard
riding it was just no longer possible to sustain
an uncomfortable aero position. Riders couldn't
take it any longer.
Yet it's these same riders who complain that they,
"ride a road bike because it's to
uncomfortable to ride a tri bike for 56
miles." Notwithstanding that I, with my
80-degree tri bike, was out of the aero position
for perhaps 20 seconds during the entire ride,
I'll stipulate to that point. Maybe a road bike
was a better bet for all those people. But
heavens, it can't be right if you're not able to
spend 25 or 30 miles in the aero position without
abandoning it, right?
To that end, I'll
share a letter I recently received from a reader,
who writes the following:
"If you have
time I have a question for you. I just read your
update to the Tri Bike Fit. I seemed to
understand the bike fit article better than when
I read your original article. I'm riding a
Litespeed Saber. I had what I believed was a
professional fit to my bike. It cost a
professional amount, $200, but I'm not sure of
the benefit to me as a triathlete. The fitter, [I'll
omit the name, it was a well-known tri bike fit
professional], had my seat as far back as
possible on an already set-back Easton Carbon
seat post. His rationale was that the plumb line
from behind my knee cap was too far forward of
the pedal spindle when at the 3 and 9 o'clock
positions. His goal for my knee angle was 140 -
145 degrees. With his setup I could not ride in
the aero position more than a few minutes. I was
uncomfortable. I kept sitting up and riding on
the bullhorns. This totally negated the benefit
of my tri bike. I moved the seat forward after a
couple of weeks and can ride in the aero
position as long as the terrain allows. After
reading your article, I move my seat forward to
be in line with my seat tube and raised the seat
to achieve 153 degrees in my knee angle. Now
finally to my question. Do you concern yourself
with knee position over the pedal spindle? If
so, do you use center mass of the knee joint,
behind the knee cap, or the front of the knee
cap?
"Thanks
for your time and the updated article. It has
provided more useful info than the fitting I
received."
This person
could've used a laid-back position, but not with
the full aero bar at its full extension, as the
bike was originally spec'd. At least, if you're
going to choose a road bike and road position,
choose an aero bar that allows you to maintain
that 90-degree shoulder angle. My favorite has
been the Profile Design Jammer GT, but there are
others, such as a couple of designs shown here
by Deda Elementi (I'd shorten the bar above quite
a bit more than the photo suggests, and I may or
may not even use the armrests—I might just wrap
the tops with a couple of rolls of bar tape). I
don't think the perfect aero position bar for road
position riding has yet been invented, but there
are some that make a decent attempt—examples
would be these by Deda, the Profile Design bars,
and Cinelli's Spinaci and Spinacissimi.
Should you desire a steeper-angled bike, you can
either choose a bike that is already sufficiently
steep, or a shallower one might work if it's also
long in the cockpit. I, for example, like my bikes
steep, like 80 or 81 degrees. I also like them low
in front, and short in the cockpit, like 55cm or
56cm of top tube (my road race bikes have 60cm of
top tube). I can make a 76- or 77-degree bike
work, however, if it's got 58cm or 59cm of top
tube. Certain QR and Felt bikes are good for me in
this respect. By the time I move the saddle
forward (by any number of means) the bike is both
steep and short enough for my liking.
This assumes, though, that the front end is low
enough. It's hard for me to get my bars low enough
on a 700c-wheeled bike if the head tube is longer
than 13cm or 14cm. I can live with a 15cm head
tube if its got an integrated headset, because now
there is 15mm to 20mm worth of headset
"stack" that I don't have to worry
about, because the headset paraphernalia is inside
the head tube.
So what do I do if I want to ride an Aegis Trident
in my size, which has 17.5cm of head tube and a
non-integrated headset? It's hard to get my bars
low enough, and I'm pretty well stuck unless I
also decide to ride with a lower-profile aero bar.
I can ride a Trident quite nicely if I've got a
HED aerobar or a VisionTech—assuming I'm not
using any armrest riser kits, or Vision's plush
aftermarket armrests that raise the elbow position
quite high above the centerline of the base bar.
Conversely, if you're thinking of retrofitting
your existing bike with one of these slick
aftermarket bars, consider what aerobar you're
currenty riding. A Profile Aerolite has armrests
that sit about 7cm above the centerline of the
pursuit bar, and other Profile bars, and Syntace
bars, have about 6cm of rise. The HED aero bar's
pads sit 2.5cm above the pursuit bar's centerline.
So, if you take off your Profile Aerolite and
replace it with the HED, your arms are going to be
sitting 3.5cm lower to the ground (all other
things equal). You'll need a new stem, or something,
if you want to achieve your previous position.
This might seem complicated, but it's not. It's
just stuff you need to keep track of. With road
race riding, there are a lot of road bars out
there, but from a positioning perspective a bar's
a bar. With tri bars, as with tri bikes, there are
wide variations in position across every axis.
When you're considering a bike, where along the
continuum is your desired position? Make sure the
bike, and the aero bars, allow you to achieve the
90-degree angles written of above while in this
position.
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