get_cs_length: Get the chain stay length

In ghuiber/bicycle: Design a bicycle frame

Description

In the plane that is perpendicular onto the bike, the chain stay is part of a trapezoid that is as wide as half the OLD spacing at the dropout and half the bottom bracket shell center offset at the bottom bracket. The OLD spacing is standard (130 mm for road bikes, 135 mm for old-school mountain bikes, 142 mm for newer mountain bikes, etc.). So the OLD spacing is an input in frame design, not a derived dimension. If you have a bottom bracket shell with a given angle between chain stays (angle_btw_css) and center offset (bbsc_offset) then you must use this function to determine the chain stay length that will produce the OLD intended for your frame.

Usage

get_cs_length(old_spacing, angle_btw_css, bbsc_offset)

Arguments

old_spacing	Over-locknut-dimension (hub width) in millimeters.
angle_btw_css	Angle between chain stays, in degrees.
bbsc_offset	The bottom bracket shell offset in millimeters.

Value

A scalar equal to the chain stay length in millimeters.

Examples

get_cs_length(130, 10, 10)

ghuiber/bicycle documentation built on Dec. 20, 2021, 10:46 a.m.