How to use this bike size chart
Start with the table for the kind of bicycle you are considering. Road and mountain rows name frame sizes; the children’s table names wheel diameters in inches. The numbers are not interchangeable. You can read every table without entering anything. To locate possible rows, enter your height and choose cm or inches. Matching rows across all three tables are highlighted automatically.
Use the highlighted rows as a shortlist to compare with the exact model you intend to ride. The chart keeps overlapping ranges rather than choosing one answer on your behalf. Clear removes your entry and highlighting.
Measure before comparing
Take off your shoes and stand upright against a wall, looking straight ahead. Measure vertically from the floor to the top of your head. For inside-leg length, stand with your feet slightly apart and ask someone to measure vertically from the floor to your crotch. The B line shows this distance beside the figure. Do not use a trouser label or follow the curve of your leg.
The inside-leg ranges shown for children come from the cited guide. Adult tables here are height references only: they do not calculate a frame from inside leg. Compare your inside leg with the exact bike’s standover measurement and check reach, saddle adjustment and handling in person.
Two ways to read the tables
At 175 cm, the road reference includes S and M. Its mountain reference includes M. These are different model references, so the letters are not a conversion between frame geometries. At 120 cm, the children’s height ranges include both 16-inch and 20-inch wheels. The corresponding inside-leg ranges and the child’s ability to start, stop and handle the bicycle help narrow that choice.
Inch equivalents are converted from the published dimensions and displayed to two decimals. Matching uses the underlying values, not the rounded display. The children’s open-ended 26-inch row is reproduced as an open range; it is not a claim that all tall adults should use a children’s bicycle.
Scope and practical limits
The road table is Giant TCR Advanced 2 (KOM), model year 2026. The mountain table is Giant Talon 1, model year 2027, using the sizes present in that page’s sizing guide. Other sizes mentioned in a product specification are not assigned invented height ranges. The children’s rows come from Trek/Electra’s guide. Other models and years can use different dimensions and recommendations.
This page offers a comparison starting point, not a final fitting guarantee. A frame label such as M does not specify a universal seat-tube length. Likewise, a 29-inch mountain wheel describes the wheel, not the rider’s frame size. Check the source and the bicycle’s geometry before purchase, and use a test ride or qualified fitting when deciding between sizes.
Frequently asked questions
Why are two rows highlighted? Manufacturers often publish overlapping height ranges. Body proportions and riding position can make either a candidate; height alone does not settle the choice.
Can I buy a bigger bike for a child to grow into? Choose a bicycle they can control now. A larger future fit can interfere with starting, braking and getting on or off today.
Why is there no result for my height? The selected references have limited coverage and some gaps. The page leaves those gaps visible rather than extrapolating.
Is inside leg the same as trouser inseam? No. Measure the vertical floor-to-crotch distance as shown; garment measurements can differ.
Matching happens in your browser. No account or saved profile is needed.