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Bicycle handlebar diameters: 22.2, 23.8, 25.4, 26.0, 31.8 and 35.0 mm
What diameter is a bike handlebar? · Standard part · basis: Clamp and grip diameters from Sheldon Brown's handlebar crib sheet and BikeGremlin's handlebar standards; current popularity of 31.8 and 35 from Bikepacking.com's stem-clamp survey
Exact dimensions. Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part. Mating features
- sizes
- 8 in table
Notes
- A bar has two diameters that matter: the clamp section in the middle (where the stem holds it) and the grip section out to the ends (where grips, brake levers, shifters, lights and phone mounts go).
- Flat and riser bars are Ø22.2 (7/8 in) at the grips whatever their clamp size; drop bars are Ø23.8 (15/16 in) at the hoods and drops.
- Clamp sizes in use: 22.2, 23.8, 25.4 (the ISO size), 26.0 (Italian drop bars), 31.8 (oversized, the most common today) and 35.0 (modern trail bars). Older bars also came in 25.0 (French), 25.8, 26.4 and 27.0, not drawn here.
- Files: each diameter as a Ø × 100 mm section, axis on X, plus a DXF of the circle. They are the outside of the bar only: wall thickness differs between bars and is not part of the interface, so the inside is not drawn.
- Most bars swell or taper between the clamp and the grip section; measure where your part will sit. A clamp drawn to the bar Ø closes onto the bar: see handlebar-clamp-rings.
Sizes
| clamp or section Ø (mm) | inch | where it is used | from |
|---|---|---|---|
| Ø22.2 | 7/8 in | BMX bars, older mountain bikes and small children's bikes; also the flat-bar grip, brake-lever and shifter section | Sheldon Brown, BikeGremlin |
| Ø23.8 | 15/16 in | the drop-bar grip, brake-lever and bar-end section; also an older British clamp size on 3-speeds | Sheldon Brown, BikeGremlin |
| Ø25.4 | 1 in | the ISO clamp size: most upright bars, older drop bars | Sheldon Brown, BikeGremlin, Bikepacking.com |
| Ø26.0 | — | the Italian drop-bar clamp size | Sheldon Brown, BikeGremlin |
| Ø31.8 | 1 1/4 in | the oversized clamp: the most common clamp size today on road, gravel and mountain bars | Sheldon Brown, BikeGremlin, Bikepacking.com |
| Ø35.0 | 1 3/8 in | the 35 mm clamp on modern mountain (trail) bars | Sheldon Brown, BikeGremlin, Bikepacking.com |
| grip section, flat bars | Ø22.2 (7/8 in) | with clamp 22.2, 25.4, 31.8 or 35.0 | Sheldon Brown, BikeGremlin |
| grip section, drop bars | Ø23.8 (15/16 in) | with clamp 23.8, 25.4, 26.0 or 31.8 | Sheldon Brown, BikeGremlin |
Mating features
Drawn at the exact size. Open press, slide, run and socket features by your process's clearance; leave designed gaps and clamp fits as drawn.
| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| bar outside | Ø22.2 / 23.8 / 25.4 / 26.0 / 31.8 / 35.0 | stem, lever, grip or mount clamp of the same Ø | clamp | bar-* |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| Sheldon Brown (Harris Cyclery) | Handlebar and stem dimension crib sheet: clamp and grip diameters | web | reference verify |
| BikeGremlin | Bicycle handlebar dimension standards: clamp 22.2 to 35 mm, grip 22.2 / 23.8 mm | web | reference verify |
| Bikepacking.com | Stem clamp diameters: a brief history and survey results (31.8 most common, 35 on trail bikes) | web | reference verify |
Free files
★ Free files 6 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json
| bar-22.2-L100 | Handlebar section Ø22.2 (7/8 in) × 100 long, axis on X: the outside of the bar (the wall is not drawn); DXF = the exact Ø22.2 circle | STEP · STL · DXF |
| bar-23.8-L100 | Handlebar section Ø23.8 (15/16 in) × 100 long, axis on X: the outside of the bar (the wall is not drawn); DXF = the exact Ø23.8 circle | STEP · STL · DXF |
| bar-25.4-L100 | Handlebar section Ø25.4 (1 in) × 100 long, axis on X: the outside of the bar (the wall is not drawn); DXF = the exact Ø25.4 circle | STEP · STL · DXF |
| bar-26.0-L100 | Handlebar section Ø26.0 (—) × 100 long, axis on X: the outside of the bar (the wall is not drawn); DXF = the exact Ø26.0 circle | STEP · STL · DXF |
| bar-31.8-L100 | Handlebar section Ø31.8 (1 1/4 in) × 100 long, axis on X: the outside of the bar (the wall is not drawn); DXF = the exact Ø31.8 circle | STEP · STL · DXF |
| bar-35.0-L100 | Handlebar section Ø35.0 (1 3/8 in) × 100 long, axis on X: the outside of the bar (the wall is not drawn); DXF = the exact Ø35.0 circle | STEP · STL · DXF |
Plain text: sheet.txt · JSON: /api/geometry?object=bicycle-handlebar-diameters
How it fits
Connects to
Handlebar clamp ringssplit clamp ring with the bore = the bar Ø (clamp)Alternatives
Bicycle seatpost diametersthe other round tube people clamp toAlso needed
17 mm ball joint for phone mountsa 17 mm ball on the clamp for a phone headYou might also need
Questions
What diameter is a bike handlebar?
At the grips: Ø22.2 mm on flat bars, Ø23.8 mm on drop bars. At the stem clamp: 31.8 mm on most current bikes, 35.0 mm on many modern mountain bikes, 25.4 or 26.0 mm on older bikes.
What size is a 31.8 handlebar at the grips?
Ø22.2 mm on a flat bar and Ø23.8 mm on a drop bar: 31.8 is only the clamp section in the middle.
What diameter should a phone or light mount clamp be?
The diameter where it sits: Ø22.2 out on a flat bar, Ø23.8 on a drop bar, or the clamp size (usually 31.8 or 35.0) next to the stem.
Is 25.4 the same as 1 inch?
Yes: 25.4 mm is exactly 1 in, the ISO clamp size.