BILL BOSTON CYCLES
The History of ACCUFIT
I first started building custom frames in 1972, I would typically spend three to
four hours interviewing customers to get information about their riding style to
learn what they liked and, most importantly, what they disliked about their
current bike. I also closely watched them ride and made many notes.
I gained experience, I asked better questions and got better answers. What was significant
was that I was able to provide a better ride and fit for my customers on their
new bikes than they had had previously. The problem was that I was uncomfortable
departing radically from a rider’s current design because it was difficult to
confirm that the new riding position would be more comfortable and efficient.
However, in late 1974 I was forced to do exactly that.
radical departure led to the development of bikes with small front wheels for
riders under 64 inches in height. For the full story see
Those bikes with small front wheels.
what does this have to do with a computer fitting system? Actually, quite a bit.
I was willing to take the risk of building a new design based on gut instinct,
and it all worked out. In fact, the design was one of my most successful and
some years later was adopted by Georgina Terry as part of her line of bicycles
for women. I felt that my customers and I would be more comfortable with the
designs that I was proposing if they could actually sit and pedal in the
position that I was proposing. This led to the design and construction of ACCUFIT
in April of 1976.
1.0 is an adjustable fitting stand. It has adjustable bottom bracket height, top
tube height, top tube length, and a sliding bottom bracket to allow me to
approximate a wide degree of seat tube angles. By this time I had built several
tandems and this provided another set of challenges, namely that of providing
enough room for the rider in the back without unnecessarily lengthening the
wheelbase. I decided to incorporate tandem design into the fitting stand and
have never been sorry.
the years, I searched for a good starting point for fitting bicycles. I began
studying the C.O.N.I. Cycling manual. I learned that it was an early collection
of empirical data gathered by measuring riders and their bikes and then
compiling that data into tables. I tried to graph the tables but was unhappy
with the resulting curve -- as riders got
larger, their bikes got relatively smaller. Just the opposite happened at the
other end of the spectrum for short riders.
sat scratching my head for a while until I realized what the graph was telling
me. Bikes for average-sized riders
(68 –71 inches tall) fit well but shorter riders were getting bikes that were
too large and taller riders were getting bikes that were too small. These racers
were successful despite their bikes, not because of them, so clearly
C.O.N.I.’s was not the approach I wanted to follow in developing a fitting
system that would work over a wide range of rider sizes.
continued to look at the problem and work with the fitting stand, but in the
back of my mind I was always looking for a better solution, a solution that
would allow me to do a good job of sizing custom frames without forcing people
to come to my shop.
hardware made that a tough endeavor until late 1981 when I purchased an HP-41C
programmable calculator capable of storing programs on small magnetic cards. I
was definitely in the push button design mode until someone introduced me to a
PC in 1983. Then I wrote a program where I could type in most of the variables.
Suddenly, in one keystroke and less than a minute later, I would have all of the
dimensions I needed to build a frame. I was hooked.
December of 1983, I purchased my first computer, a Hewlett Packard 150 that had
a touch screen, which made selecting menu items very easy. I spent the next 3
months writing a program for completely designing frames. It included selection
items for wheel sizes, types of lugs, fork crowns, and headsets -- all available
from on-screen menus. Output was provided in various categories that included
customer data, machine shop data (for cutting and mitering tubes), hardware
data, fixture set up data, and a graphical representation of the frame, forks,
and wheels. This technology for the first time allowed me to consider hundreds
of design options in a matter of minutes. I could fully optimize my designs and
see possible design problems that would have been otherwise overlooked.
But what about fit?
was so enthusiastic about the success of the frame design software, I decided to
tackle the fit problem. I spent a great deal of time talking about anatomical
limits, anatomy, and kinesiology with doctors and physical therapists
(fortunately, a lot of them were riding my frames and had a vested interest in
the problem). After a couple of months and a lot of help from my friends and
customers, I was ready to start programming.
the way, I discovered that I was going to need a method of taking measurements
that would be both accurate and reproducible. After a couple of tries, I
developed the ACCUFIT Caliper.
This was available in both a wall mounted version and a portable model that I
used at trade shows and bicycle rallies. After a great deal of fine-tuning, I
now had a tool that I could use to produce accurate fitting information for a
wide range of body sizes. In fact, I used it to track the growth of my son Brad
and used it to check the fit of his first bike. In fact, I was actually quite
amazed when the graphics produced by Accufit closely resembled his position on
later built an anatomical database and rewrote Accufit to use that data. This
allowed me to explore the realm of bike fit with regard to the population as a
whole and to design very efficient lines of production bicycles that fit up to
90% of the population rather than the 50 to 55% average for most production
So what have
I been doing lately?
the early ‘80’s my dream was to provide ACCUFIT technology to bike shops as
a tool that would fit their customers and then easily select the best fitting
bike from their stock or from a manufacturer. Unfortunately, because few bike
shops back then could afford computers, my dream stalled but not my interest in
1985, despite overwhelming interest from bikers at trade shows, I hung up the
torch, retired the fitting system, and spent the next eight years providing CAD
and IT support to a small engineering firm that did consulting for one of
Fortune’s top 10 companies.
was followed by another seven years working for a software company that produced
CAD and engineering applications. These jobs taught me a great deal about
database applications and software design and development. During that period,
my interest in bicycle technology never wavered as I worked to stay abreast of
current technology. At the urging of many of my friends and my son Brad, now a
computer engineering student at Drexel, and after looking at current designs on
the market, I decided to rebuild my bicycle design technology from the ground up
using all of the modern programming tools available for Windows.
am happy to say that the development work has gone well and the products
outlined on this web site are the culmination of that effort.
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Copyright © 2003 BILL BOSTON CYCLES