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Get Fit!
Fitting your bike in 4 simple steps
The group of people I train with like to call me "Eddy Merckx."
No, not because I’m a cannibal on the bike (I don’t even eat
meat), but because, like Merckx, I’m constantly changing my position
by a millimeter here and a millimeter there. It’s an obsession for
me--clearly not a healthy one--but I’m always either in search of
that magic spot, or trying to get rid of a pea under my mattress.
Whether you spend 5 hours a week on your bike or 35, a proper fit can
make all the difference in the world. Like many aspects of training for
cycling, bike fit is a type of quasi-science, with a lot of folk knowledge
and old school adages mixed in with some attempts at real measurements
of performance changes based on certain angles and lengths. A balance
between both is in order, since the science tells us what should be the
case, while the real world experience tells us how it actually feels.
Either way, there are 4 primary measurements that will simplify things
to a point, and allow you to maintain a consistent fit from one bike to
the next: saddle height, saddle setback, handlebar reach, and handlebar
drop. Cleat position on the shoe is also important, but requires an article
in and of itself. Of course, each measurement affects the other, so it’s
important to set your position up in a particular order, starting with
height.
Saddle Height
I measure saddle height as a plane from the center of the bottom bracket
spindle (using the center of the crankarm bolt) to the lowest (or deepest)
part of the top of the saddle. If you look at most saddles, they have
a dip or hammock shape, and that deepest part is typically where you’ll
be sitting when going hard, provided your saddle is properly leveled.
(Though I shouldn’t take a level saddle for granted, as this is one
of the changes I make most often when doing bike fits. To use any saddle
properly and have leverage on both the front and back parts of the curve,
you should ideally be riding with a level saddle, or very close to it.)
By using that deepest part of the saddle as your top point, you’ll
be able to keep your height consistent between saddles and bikes. Don’t
simply go straight up the seatpost, since that has no relation to where
you’ll actually be sitting.
To determine a 1-2 centimeter range or starting point for ideal saddle
height, I rely on the "Lemond Factor:" a measurement of the
inseam multiplied by .883. I find that this gives me a low setting from
which I can work upwards, though sometimes it’s right on the money.
It was originally formulated for 170mm crankarms and pedals with toe clips
and straps, but with longer crankarms and clipless pedal systems, some
of the slack is taken up.
What I look for after setting the saddle height is for the rider to have
a flat forefoot and slightly heel up position at the bottom of the pedal
stroke, without over-extending behind the knee or rocking in the saddle
to do it. Many coaches rely on a specific upper and lower leg angle of
anywhere from 28-35 degrees. I find it just as important to simply watch
a rider’s pedaling dynamics as well. The key is to be able to apply
force all the way down through the pedal stoke, without dropping the heel
at the bottom and delaying the time it takes to begin pulling back and
up on the pedals on the upstroke. If you’re setting your position
up for cyclo-cross or mountain biking, you might be up to a centimeter
below your optimal road position to allow for riding slightly over the
saddle on bumpy terrain.
Saddle Setback
Once you’re within a range for saddle height, the next aspect to
consider is saddle setback. Your setback is measured as the distance between
the vertical planes of the center of your bottom bracket and the nose
of your saddle. When doing a bike fit, it’s important that the bike
is on a level surface. If you have a level top tube, that’s easy
enough to determine with a small carpenter’s level. It’s especially
important when measuring setback, as a tilted bike could put your measurements
off by .5 to 1 centimeter.
You’ll also need a plumb bob for this, which you can get at any hardware
store for a few dollars. First, drop a plumb from your top tube bisecting
the bottom bracket spindle, and make a small dot with a marker at that
point on your top tube. Then, drop the plumb from the nose of your saddle,
and mark that point on your top tube. Again, if you have a level top tube,
you now have your setback measured plainly right there on your bike, making
it easy to make changes. If you don’t have a level top tube, drop
the plumb from the nose of your saddle and mark the chainstay. Then you
can measure directly from the bottom bracket spindle to that point.
To measure proper setback, you’ll need an assistant. Drop a plumb
line from the soft part of your knee right below your knee cap (and not
the front of you knee cap) with your crankarm in the forward, horizontal
(3 or 9 o’clock) position. The ball and heel of your foot should
be level or slightly heel up, depending on your pedaling style. In this
position, the plumb should bisect your pedal axle as a median point. There
are many variations and arguments for being slightly forward or back from
this point, and they depend mostly on your build and the types of events
you focus on. If you have large joints and bones, or focus on an event
that requires maximal, instantaneous power like criteriums, track, or
cyclo-cross or mountain biking, you’ll likely bisect the spindle
or be up to a centimeter in front of it. If you’re smaller-boned
or focus more on longer road or stage races, you might still bisect the
spindle or be up to a centimeter or more behind it.
Being over or in front of the spindle puts more emphasis on your quadriceps
and really maximizes the power created on the downstroke. The further
back you move, the more you engage your hamstrings and de-emphasize the
quads. They key is to either find a good balance, or favor one side based
on your event.
Handlebar Reach
Now that your saddle position is hopefully set, you can begin to focus
on the front end. Reach is measured as the distance from the nose of your
saddle to the center of your handlebars across the top. What your looking
for in a neutral road position is a reach that gives you a right angle
from your torso to your upper leg between the 3 and 6 o’clock position,
and a right angle from your torso to your upper arm with your hands on
the brake hoods.
Many riders who suffer from shoulder and upper back pain mistakenly shorten
their reach, thinking it’s caused by their bars being too far away.
Often it’s just the opposite; a short reach causes them to shrug
their shoulder to take up the slack, leading to pain between the shoulder
blades and below the neck.
At the same time, the further away your bars are the more your bike handling
is compromised. If you’re focusing on ‘cross or criteriums,
you might set yourself up a little short, so that you can reach your hoods
while still in a somewhat upright position. If you’re strictly a
road rider or someone who likes to attack and ride solo, you might push
things to a longer, more aerodynamic set up.
Drop
Drop is measured as the distance between the horizontal planes of the
deepest point of the top of your saddle and the center of your handlebars.
(You can use the top rather than the center, but since many bars are different
diameters I prefer the center.)
Again, how you set your drop is based somewhat on your discipline. If
this is your road bike and aerodynamics are a concern you should set your
drop as low as you can tolerate without compromising breathing room or
pedaling dynamics, trying to achieve a flat back when in the drops of
your handlebars. Be cognizant of the point at which your pedal stoke suffers,
you can’t handle your bike, or your thighs touch your abdomen. Aerodynamics
isn’t helpful if the gains are negated by a loss in power output.
If you’re setting your position up for cyclo-cross, you might prefer
to be able to reach the drops for descents or technical sections without
having to bend over past that right angle point of your torso, and so
set your drop very high.
There are many, many small measurements and adjustments I make when setting
a rider up in person. But by focusing on these main four, you have most
of what you’ll need to set your position up, make changes when needed,
and transfer that position from bike to bike.
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