| 3/32" | 2.38 mm | Chain/chainring width for derailer-equipped bicycles, up to 8-speed |
|---|---|---|
| 1/8" | 3.175 mm | Bearing balls: freewheels, some headsets, some pedals Chain/chainring width for most one-speed bikes (frequently rounded to 3 mm) |
| 5/32" | 3.969 mm | Bearing balls: many headsets, many pedals |
| 3/16" | 4.763 mm | Bearing balls: most front hubs (10 x 2) many headsets |
| 7/32" | 5.556 mm | Bearing balls: high end Campagnolo front hubs (9 x 2) |
| 15/64" | 5.953 mm | Bearing balls useful for mismatched bottom bracket cup and spindle |
| 0.236" | 6.000 mm | Bearing balls useful for mismatched bottom bracket cup and spindle |
| 1/4" | 6.35 mm | Bearing balls: almost all rear hubs (9 x 2) Most bottom brackets (11 x 2) |
| 5/16" | 7.938 mm | Bearing balls: bottom brackets for one-piece-cranks. |
| 0.833" | 21.15 mm | BMX & OPC stems, seatposts |
| 0.866" | 22.0 mm | French handlebar stems |
| 7/8" | 22.2 mm | Upright handlebars (grip section), 1" stem quills, BMX Seatposts |
| 15/16" | 23.8 mm | Drop handlebars (grip secction) |
| 1" | 25.4 mm | ISO handlebar clamp size, standard top tubes. |
| 1.024" | 26.0 mm | Italian handlebar clamp size, many higher-end road bars. |
| 1.039" | 26.4 mm | Old Cinelli handlebar clamp size |
| 1 1/16" | 27.0 mm | |
| 1 1/8" | 28.6 mm | Standard steel seat tubes, down tubes, O.S. top tubes |
| 1 1/4" | 31.8 mm | O.S. seat tubes, O.S. handlebar clamp size, others |
| 1 3/8" | 34.9 mm | O.S. seat tubes, others |
| 17" | 43.2 cm | Frame sizes listed in inches are most often "center to top." |
| 18" | 45.7 cm | |
| 19" | 48.3 cm | |
| 20" | 50.8 cm | |
| 21" | 53.3 cm | |
| 22" | 55.9 cm | |
| 23" | 58.4 cm | |
| 24" | 61.0 cm | |
| 25" | 63.5 cm |
Last Updated: by Harriet Fell
