Originally Posted by
Foldable Two
They publish the effective top tube length of the various sizes:
Question:
What FRAME SIZES do you make, and how do they compare to a normal bike?
Answer:
A Bike Friday frame is sized according to 8 "effective" top tube lengths. The Effective Top Tube is the distance from the center of the headtube to the the center of the seat tube measured horizontally. This number is equivalent to the top tube length on a standard pre-2000 road bike with a horizontal top tube.
XXS = 48cm = 18.9"
XS = 50cm = 19.7"
S = 52cm = 20.5"
S/M = 54cm = 21.25
M = 56cm = 22"
L = 58cm = 22.8"
XL = 60cm = 23.625"
XXL = 62cm = 24.4"
chiming in only 10 years late here but if someone is still here....
I am looking at 2nd hand BFs. how then would you measure it's effective top tube to work backwards to it's factory size? from what point to what point? I don't know where you would find the equivalent of the center of the headtube and the centre of the seattube on a BF.
would you say A or B in the attached photo. (though if the headtube and seattube on a BF are virtually parallel then A will be the same as B I guess.)