D
Death
Guest
Hello,
I am in the process of putting together a new bike and I am having trouble making a decision of
which of two frame sizes I should choose. I know that the right answer is to ride both sizes and
pick the one that fits best, unfortunately I do not have this option. There is no dealer near me
that carries the brand I am interested in(Soma) and even if there were it would have to be an
exceptional shop that would stock several different sizes of fixed gear/track frames. I have lived
in cities where exceptional shops existed, I miss them.
I recently paid a local Serotta dealer to fit me using their Size Cycle. According to the data sheet
generated by this fitting I will be the most comfortable on a frame with a 57 cm seat tube
length(measured center to center) and a 56.5 cm top tube using a 11 cm stem.
I am having difficulty deciding between a 57 or a 59 frame. Soma measures their frames center to the
top of the seat tube, so I am guessing that their 57 measures 56 c to c and their 59 measures 58 c
to c. The top tube for the 57 is 56 cm and the top tube for the 59 is 57.5 cm. The standover on the
57 is 32.5" the 59 is 33.3" my inseam is 33.6". I suppose my question boils down to this: would I be
better off with more seat post extension and a longer stem(12 or 13) or less seat post extension and
a shorter stem(9 or
10)? And should I worry about only having .3" between the top tube and my crotch while standing if I
choose the 59?
The Size Cycle measurements were made to determine an ideal road bike frame, so the bottom
bracket of my target geometry has a 26 cm height, the Soma track frame has a 27.5 cm bb height.
Also, the head & seat tube angles are about 1.5 deg sharper on the track bike than the imaginary
ideal road bike.
You say you want more information? No problem: I am 6'1, 33.6" inseam. The bike I currently have for
road/light off road use(the first non mountain or BMX bike I have owned) is a Kona cyclocross bike,
58 cm center to top of seat tube, 57 cm top tube and a 10 cm stem. It shows about 6.5" of post to
the bottom of the seat. It has a 31.2 cm bb height & 33.1" standover. I think it fits pretty well,
but could be better.
I plan to use the new bike with a fixed gear and ride almost exclusively on 20-30 mile trips over
mostly flat road. I realize an off the shelf frame will never match what is calculated from a custom
fitting, and perhaps given the intended application of this bike(mostly short, training oriented
rides) maybe perfect comfort fitting is not all that important. But I have made some bad equipment
decisions in the past because I did not do enough research or ask the right questions, and I would
really like to have peace of mind with this decision so that I can concentrate on using the bike. I
know that there are some folks here who have much more experience with frame sizing than myself and
if any of you have made it this far, to the end of my autobiography, I would greatly appreciate any
input or suggestions you may have.
I am in the process of putting together a new bike and I am having trouble making a decision of
which of two frame sizes I should choose. I know that the right answer is to ride both sizes and
pick the one that fits best, unfortunately I do not have this option. There is no dealer near me
that carries the brand I am interested in(Soma) and even if there were it would have to be an
exceptional shop that would stock several different sizes of fixed gear/track frames. I have lived
in cities where exceptional shops existed, I miss them.
I recently paid a local Serotta dealer to fit me using their Size Cycle. According to the data sheet
generated by this fitting I will be the most comfortable on a frame with a 57 cm seat tube
length(measured center to center) and a 56.5 cm top tube using a 11 cm stem.
I am having difficulty deciding between a 57 or a 59 frame. Soma measures their frames center to the
top of the seat tube, so I am guessing that their 57 measures 56 c to c and their 59 measures 58 c
to c. The top tube for the 57 is 56 cm and the top tube for the 59 is 57.5 cm. The standover on the
57 is 32.5" the 59 is 33.3" my inseam is 33.6". I suppose my question boils down to this: would I be
better off with more seat post extension and a longer stem(12 or 13) or less seat post extension and
a shorter stem(9 or
10)? And should I worry about only having .3" between the top tube and my crotch while standing if I
choose the 59?
The Size Cycle measurements were made to determine an ideal road bike frame, so the bottom
bracket of my target geometry has a 26 cm height, the Soma track frame has a 27.5 cm bb height.
Also, the head & seat tube angles are about 1.5 deg sharper on the track bike than the imaginary
ideal road bike.
You say you want more information? No problem: I am 6'1, 33.6" inseam. The bike I currently have for
road/light off road use(the first non mountain or BMX bike I have owned) is a Kona cyclocross bike,
58 cm center to top of seat tube, 57 cm top tube and a 10 cm stem. It shows about 6.5" of post to
the bottom of the seat. It has a 31.2 cm bb height & 33.1" standover. I think it fits pretty well,
but could be better.
I plan to use the new bike with a fixed gear and ride almost exclusively on 20-30 mile trips over
mostly flat road. I realize an off the shelf frame will never match what is calculated from a custom
fitting, and perhaps given the intended application of this bike(mostly short, training oriented
rides) maybe perfect comfort fitting is not all that important. But I have made some bad equipment
decisions in the past because I did not do enough research or ask the right questions, and I would
really like to have peace of mind with this decision so that I can concentrate on using the bike. I
know that there are some folks here who have much more experience with frame sizing than myself and
if any of you have made it this far, to the end of my autobiography, I would greatly appreciate any
input or suggestions you may have.