Originally Posted by
bus_ter
I've taken all my measurments using the comprehensive 'Fit Calculator' at
http://www.competitivecyclist.com. However my suggested measurements for a frame don't match up with the proporitions of real frames.
For example if we look at probably the two main measurements
'Effective Top tube length' and
'Seat Tube centre to Top', the Fit calculator suggests respectively 'aprox'
560mm and
600mm (and greater for a more relaxed fit).
A 600mm Seat tube (c-t) equates to a very large frame, however the 560mm Top Tube length equates to a much smaller frame. For example on the bike I own now 'Dawes Giro' I would have to buy a 53cm frame to get that top tube length. I have their largest frame (58cm) and already find the riding position aggressive and can't imagine going to a smaller frame.
What's going on? Are my body measurements freakish? (see below) or am I missing something?
Thanks to anyone who reads all this and puts in the time to make sense of what I'm saying. I appreciate it!
------------------------------- My measurements
Gender M
Inseam 89.1 cm
Trunk 66 cm
Forearm 35.5 cm
Arm 70 cm
Thigh 63 cm
Lower Leg 57.3 cm
Sternal Notch 53.2 cm
Total Body Height 185 cm
------------------------------- Fit Calculator Output for 'Competitive fit'
Seat tube range c-c 57.7
Seat tube range c-t 59.5 - 60.0
Top tube length 55.9 - 56.3
Stem Length 11.8 - 12.4
BB-Saddle Position 79.3 - 81.3
Saddle-Handlebar 55.8 - 56.4
Saddle Setback 6.8 - 7.2
------------------------------
as noted, you are torso short, leg long
I'm pretty much the same way, except you might be more 'extreme' on that end.
Things I've found...
Short torso, long leg usually also equates with long arms...
trying to get the long ST, short TT was a problem in the old days, not so much an issue anymore...
why?
the longer seatpost available these days menas you can downsize the frame and get the shorter TT and still get enough saddle extension.
in fact, downsizing has a favorable effect - because the torso 'weight' is in a more compact span, a smaller frame/shorter TT means you can use a longer stem and still have enough weight forward, for better handling (especially on descents...)
Caveats:
Saddle setback would be a critical dimension for longleg types like us - SO, smaller frames with steeper ST angles are best avoided. Something no more than 73 Deg. and even less, would get you the needed setback. Steeper than 73 and the setup will be tough and bike handling wil get funkier...
For example - my measurements (88 cm inseam) usually called for a 58/59 cm frame, but in modern frames I use a 56 with 73 deg ST (or less...) , 'square TT' or slightly under (usual range is 55.5 cm to 56.5 &is ok for me, and then I adjust with a 120 to 130 stem, dependin on HT height and HT angle). Arms are long enough to go plenty forward. And I have always preferred a more forward than 'upright' torso posture.
If you have to be 'upright' then try to get the shorter TT, rather than adjusting with too short a stem. Going too short ont he stem makes for really spooky handling of the front end...
in old steel I always preferred Italian Frames, since they usually had shorter TTs than English, French, Japanese or American Frames.
check out some of the 58's out there, you'll prolly find something that work real nice.
not sure how many Frame/Bike makers still spec out 57s, but that might even work for you...
BTW: I have a Marin Treviso in a 57cm (1999 Columbus NEMO steel, built for Marin by Pinarello) which is my go-to daily rider, 19.5 lbs built up, pedals and all, with 9 spd Ultegra.
Originally I bought a 59cm Treviso, built it up and rode for 100 miles, luv'd it but decided I wanted the next size down, hence the 57cm I now ride...
I still have the 59cm Treviso Frame, boxed, in the attic, in premo condition, waiting for me to get off my butt and put it up for sale... Carbon Fork, Campy chorus headset...