ADJUSTING FIT WITH COMPONENTS
Even assuming that your frame is a reasonably good fit for your body
and riding style, you should be prepared to adjust and fine tune that
fit by adjusting or replacing components on the bike. My intention
here is only to identify those components you may need to adjust or
replace. It is not to describe how to make those adjustments.
I will leave that job to others.
There are countless articles on how adjust and fine tune your fit
available on the internet. By far, one of the best articles
I've read on adjusting your fit is by Peter White at
his website.
The thing I appreciate most about Peter White's approach is he
recognizes how fit is affected by things such as the rider's style,
preference and age.
The components that have an affect on fit include the seat post, the
handlebar stem, the handlebars and the crankset. The most first and
most obvious adjustment to be made is the height of the saddle, which
is adjusted by the seat post. However, just as important is the
fore/aft position of the saddle on the seat post. The position of your
hips relative to the center of your cranks forms the foundation of
your bike fit, so together, these 2 adjustment are absolutely
critical. In nearly all cases, the seat post that comes with your bike
will provide you with the range you need to get a proper fit.
Typically the only reason people replace their seat posts is to
achieve some fashion oriented goal such as weight reduction or looks.
However, occasionally a person needs to move their saddle more
foreword or, more typically, more rearward than their stock seat post
will allow. To achieve this, you can use special "set-back" seat
posts.
Not long after the saddle height has been set with the seat post, many
cyclists conclude that the stock saddle that came with the bike needs
to be replaced. For most long distance cyclists, this is a correct
conclusion. Most modern saddles consist of plastic shells that are
covered with some sort of foam material and then wrapped in leather or
some synthetic material. Another style that has re-emerged is the
unpadded shell. I first saw (and used) unpadded plastic shell saddles
in the 1970s and today they've reappeared made from super light carbon
fiber. Lastly, and in my opinion most importantly, there is
the leather saddle; namely the Brooks line of saddles.
While I'm generally trying to steer clear
of offering specific fit and comfort advice on this page, I will say
that the Brooks B-17 has been, far and away, the most comfortable
saddle I've ever used. But saddles, like ski boots, are a very
personal issue. Different back sides demand different saddles. As a
rule, the wider your sit bones are from each other, the wider saddle
you'll need. Related, the higher your cadence is (the rate at which
you spin the pedals), the narrower saddle you'll prefer.
Another of the most frequently changed piece is, or should be, the
handlebar stem, which adjusts both your reach to the bars and the
height of your bars. The height of the bars relative to your saddle
height should be determined by your riding style (not by the well
meaning suggestions of racer wanna-bes). The standard rule of
thumb for determining the reach from your saddle to the bars is is
that this distance should equal the distance from your elbow to the
tip of your middle finger, which is a very easy test to perform.
That said, finding the best reach and handlebar height can be a
life-long quest. For this reason, it is not uncommon for experienced
cyclists to end up with a small collection of stems in their parts
bin. Worse, this can change over time. The more you ride, the more
your neck and shoulder can accommodate lower bars but the more you
age, the more you will like your bars up higher. Some better bike
shops even have adjustable stems that they can loan to customers so
they can try various combinations before buying. If your shop offers
this service, take advantage of it.
The handlebar is another commonly replaced part. Bars can
vary in terms of their width and in the distance from the top of the
bars to the bottom of the drops. And, there is a nearly infinite
number of variations in the different curves and shapes that are available. Each
bar style has its devoted fans and its not uncommon for cyclists to
try many different styles before finding comfort. Generally speaking,
bar width is related to the rider's shoulder width, but there is
plenty of room for variations here.
The last component that can be adjusted to affect fit is the crank
set. The length of the crank is the most commonly discussed variation.
One school of thought says that crank length should vary based on
femur length and concludes that tall riders should be on very long
cranks and short riders on short cranks. Another school of thought
is that crank length should be adjusted according to riding style.
According to this line of thinking, low cadence power riders should
use longer cranks and high cadence spinners should use shorter cranks.
And yet another school of though says that for many decades everybody
rode on 170mm cranks and got along OK. Each of these perspectives has
a kernel of truth in them.
The other aspect in which cranks can vary is called the tread, which is
the width of the cranks measured from the outside face to outside
face at the pedal threads. In some circles, this is called the Q-factor,
or quack-factor, as in how much the crank makes you ride like a duck.
Some folks argue that narrower is better. Others suggest that the
tread should match your hip width. And others suggest that the angle
created by your knees should dictate the ideal tread for the rider.
Most agree that tread can have an affect on knee pain. Whether you're
concerned about crank length or the tread, I think the reality is that
most folks just ride with the stock crank that came on their bike.
Quality cranks are expensive items to replace.
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SEEK LOCAL EXPERT ADVICE
Whitehead once advised, "Seek simplicity, but fear it." This leads me
to my final piece of advice on bike fit. Seek expert fit
advice, but be suspicious of it. Most bikes ship with parts on them
that will fit most people and a good number of bike shops are happy
to sell you a bike and send you on the way with no fitting help
beyond raising or lowering the saddle. And since most fit problems
take many miles to make themselves known, this approach often works,
at least for the shop.
So, if you are having fit problems, seek out a local bike shop that
offers a fitting service and that has a good reputation in this
regard. If the shop has dedicated valuable floor space to create a
fitting area, this is a positive sign that they at least want to
appear to take fit seriously.
But be aware. Many so-called fit experts either are or were racers and
the siren song of a low-bar "competitive fit" may still have a strong
influence on them. Worse, you could end up with somebody with little
fitting experience beyond running numbers through a formula based system
and reading too many racing magazines.
You should expect to pay 1-3 hour's labor rate for a good fitting
service. In return, you should demand the fitter help you achieve
your fitting goals. Don't hesitate to print off and bring in
the Competitive Cyclist essay on fitting styles and be sure to work
out a common understanding of your goals. If the fitter puts your
bars 2" below the saddle and suggests that you'll get used to it,
ask for your money back and seek advice elsewhere.
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Dave's Backcountry Skiing Page
Dave's Cycling Page
Copyright 2006 by David Mann
Bike fitting is endlessly discussed among cyclists and for good
reason. It can really make or break your cycling experience. I cannot
add much of value to the volumes that have been written on the
subject. Still, I can mention 4 points that have been helpful to me: