Stack and reach explained: why two size-54 frames can fit differently
A size label is a manufacturer’s name for a size. Stack and reach give you more useful comparison points—provided the chart is reliable and its reference is clear. They still describe only the frame, so keep the cockpit in the calculation.
In the usual frame convention, stack is the vertical and reach the horizontal distance from the bottom-bracket centre to the top of the head-tube reference. Check the manufacturer’s convention, particularly for unusual or integrated designs. These are coordinates, not a rider-height prescription.
Subtract before making a fit claim
In this made-up pair, frame B’s reference point is 20 mm higher and 5 mm nearer horizontally. That is a useful frame comparison. It does not mean the finished hoods will be exactly 20 mm higher and 5 mm nearer, because the two cockpit packages may differ.
Illustrative frame coordinates, not product measurements
Frame
Stack
Reach
A
560 mm
380 mm
B
580 mm
375 mm
B minus A
20 mm higher
5 mm shorter
LightCarbon LCR018-D · Model detailsManufacturer’s example build on the LCR018-D frameset; pictured parts are not a confirmed sale package.LightCarbon; see sourcePhoto unavailable; open the source to view it.
Add the setup you will use
Stem angle and length, spacers, bar reach and hood position affect the finished hand location. Two equal-reach frames can therefore put your hands differently. Compare complete approved configurations against your known fit, leaving adjustment room. Canyon’s geometry guide explains the distinction between frame and contact-point measures.
Use a chart that deserves the calculation
The LightCarbon LCR018-D record includes dated geometry evidence and qualifications. Respect those limits. A number transcribed from a different revision or an internally inconsistent chart cannot become a precise fit recommendation. When comparing candidates, keep the original chart, units and reference notes beside the subtraction.
