How it is calculated
Modern frames with a sloping top tube are better checked against the maker’s chart. The factor is an old guide based on the seat tube.
Road ≈ inseam × 0,67
Where the numbers come from
- Inseam — unit in the field: cm
Example
An 80 cm inseam gives a road size of about 53,6 cm and a mountain size of about 52,8 cm.
Questions
Inseam or height?
Inseam along the inside seam, not height.
Inches?
The answer is in centimeters. The length converter gives inches.
A children's bicycle?
These factors are for an adult frame. A child’s size is not picked this way.