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Saddle Height
What's
the matter? You want to be certain of your best saddle height
but just about every expert you hear or formula you see produces a
different number.
Of all the ways that your body fits your
bike, saddle height is the most important. Get it right and you'll
produce the most power that your heart, lungs and muscles can muster.
You'll escape most of the injuries inherent in doing a repetitive motion
(pedaling) for hours at a time. And you'll have the best chance of
doing it all in comfort.
But while there's widespread
agreement on a general saddle height "window," there's certainly no
consensus on the ideal for any given rider.
[To illustrate
below, Coach Fred Matheny used himself as a guinea pig and
calculated his saddle height using 4 non-commercial methods. He's
5-foot-10 (1.77 m) and has a crotch-to-floor measurement of 34.6 inches
(88 cm), which is relatively long for his height.]
How to
Measure Your Legs
This is important because the
crotch-to-floor distance is the key measurement in determining saddle
height.
---Stand barefoot with your back to a wall. Feet should
be about 8 in. (20 cm) apart.
---Put a carpenter's square or
large thin book or record album (remember those?) between your legs.
Snug it into your crotch with the same pressure you feel on a saddle.
One edge of the carpenter's square should be flush against the wall, the
other sticking out in front of you.
---Have your assistant
measure from the top of the square to the floor in centimeters (easier
to work with than inches). This is your crotch-to-floor measurement.
Note that this probably isn't the same as the inseam length of pants you
buy.
Calculations
Now as an example,
let's plug Coach Fred's 88-cm crotch-to-floor measurement into 4 at-home
methods for determining saddle height to see what happens.
Heel-on-Pedal
Method. With your bike level on a trainer, pedal until you've
settled onto the saddle in your normal position. Then unclip your feet
and put your heels on the pedals. Pedal slowly backwards. Your heels
should just keep contact at the bottom of the stroke as your legs
straighten, with no hip rocking necessary. This is dependent on the
thickness of the shoe sole and pedal body, so saddle height will change
along with these factors. After setting his saddle this way, Fred
measured from the middle of the crank axle along the seat tube to the
top of the saddle and got 76.2 cm (photo
on RBR
site).
109% Formula. Multiply the crotch-to-floor
measurement by 1.09. Set the saddle by measuring from the top of the
saddle to the top of the pedal when the crankarm is straight down in the
6 o'clock position. This ancient formula gives Fred 95.9 cm, which
results in a saddle more than 2 cm higher than method No. 1. Measured
from the center of the crank axle along the seat tube to the top of the
saddle, he got 78.6 cm.
LeMond Method. Greg LeMond
says to multiply your crotch-to-floor measurement by 0.883. This figure
was determined in the early 1980s by LeMond's French coach at that time,Cyrille Guimard. Back then, everyone was on cage pedals with toe
clips and straps and wearing leather-sole shoes with nailed-on cleats.
LeMond recommends subtracting 3 mm from the number produced by his
formula if you use clipless pedals. Fred takes off another 2 mm because
shoe soles have become thinner, too. Height is measured from the middle
of the crank axle along the seat tube to the top of the saddle. Fred's
result is a saddle height of 77.2 cm.
Pruitt Method. Andy Pruitt
checks leg extension by using a large protractor-like instrument called a
goniometer (illustration
on RBR
site, courtesy of bikefit.com). It measures the angle
of the knee when the pedal is at dead bottom center. He says saddle
height is right when the bend is between 25 and 30 degrees. Fred's
saddle height when his knee at DBC is bent 28 degrees: 77.0 cm.
Serotta
SizeCycle. To get a value using a commercial system, Wheat Ridge
Cyclery near Denver fit Fred on a popular bike fit device available to
Serotta dealers. The SizeCycle recommends a saddle height of 77.0 cm.
Notice that while Pruitt's method agrees with the Serotta
SizeCycle, those 2 recommendations are slightly lower the older methods.
One reason is that new pedal systems and shoes put your feet closer to
the pedal axle.
So where has Fred put his saddle, given the
varying recommendations? It's currently at 74.5 cm measured from the
middle of the crank axle along the seat tube to the top of the saddle.
Why is this lower than all the recommendations? Several reasons:
---Fred has moved his shoe cleats rearward in recent years as a
way to reduce "hot foot" on long rides. The cleats aren't all the way
back, but they're perhaps a centimeter closer to the heel than they were
when most of these saddle heights were calculated. Moving cleats back
has the effect of shortening the leg/foot combination. Thus, it requires
a lower saddle.
---He's using Shimano PD-7810 pedals ("Lance
pedals"), which put feet closer to the pedal axle.
---He has
moved his saddle rearward for more comfort. The tip is now 6-7 cm behind
the bottom bracket vs. about 5 cm before, depending on saddle model (he
usually rides a Fizik Aliante).
---Finally, Fred says he feels
more comfortable and powerful with a slightly lower saddle. He first
noticed this while riding his mountain bike. He lowered the saddle for
ease in dismounting and greater agility while pedaling on technical
terrain, and a byproduct was better climbing power.
What
should you make of all this? Use saddle height recommendations not
as an end in themselves but as a basis for your experiments. You have a
window to work in, as Fred's example illustrates. Use it and you'll
arrive at your most efficient, comfortable and powerful position.
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