I have so much pleasure riding my own handmade bicycle that I want to share the way I did it.
Design a bike that fits your body
It explains all the rules needed to match the size of your frame to the size of your body.
To facilitate the process, I have written all the measures you need inside a little python script called
patereck.py available in this repo:
#### parameters to choose: ##### rider A = 82 # inseam height cubit = 46 # from elbow to nails, hand opened TM = 67 # torso measurment AM = 66 # arm measurment ##### bike B = 27 # bottom braket height in cm C = 4 # crotch clearance (4cm for touting 6cm for racing) E = radians(73.2) # seat tube angle HTA = radians(72) # head tube angle:70:resilient and confort (touring) 75: stiff (race) FR = 4.5 # fork rake: + for touring - for race R = 33.4 # wheel radius
once you run it using
python patereck.py you'll find all the measurements you need:
Down Tube : 51 Seat Tube : 53.273750437 Top Tube : 54.3 ========== checks =========== Stem from torso: 3.52608695652 Stem form cubit: 9.2 Trail (5 to 7): 6.12073784511 Front center (around 58) chainstay (40 for race to 47 for touring check clearance
there are two ways to compute the stem and I guess I misunderstood one because both don't give me the same result. I chose the one derived from the cubit.
Once you've got these measurments, download RattleCad which is a free, open source version of BikeCad. It is far from being perfect but it does the work for the frame ajustments and mitering:
The mitering is particularly usefull as if you take care of printing these images without resizing, you'll just have to cut them and round them on your tube to cut them properly.
And now you're ready to do real stuff: