Handlebar clamp rings: split rings for 22.2 to 35.0 mm bars, M4 / M5 — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/handlebar-clamp-rings/  (CC BY 4.0)
Basis: Bore = the bar Ø from bicycle-handlebar-diameters; screw clearance holes ISO 273 medium; ring wall, width, ears and the 2.0 take-up gap are my design
Catalog version: 2026-10-20

Sizes: see table below
- A building block for anything that clamps on a round bar: union your phone mount, light bracket or bag hook onto the ring's outside and keep the bore and gap as drawn.
- The bore is exactly the bar diameter, so the ring touches the bar all round with no overlap; the 2 mm gap at the bottom is designed take-up: tightening the screw closes it and grips the bar (fit class clamp).
- Ring wall 4, width 16. Bars up to Ø26.0 take one M4 screw (Ø4.5 clearance, 5 mm ears); Ø31.8 and Ø35.0 take one M5 (Ø5.5 clearance, 6 mm ears). The screw and nut are the catalog's ISO 4762 screws and ISO 4032 nuts.
- Fit check: each ring placed on its bar section from bicycle-handlebar-diameters: zero common volume and zero distance (touching), see files/assemblies/handlebar-clamp-fit-report.json.
- The same rings fit any round tube of the same Ø: seatposts of equal size, e-scooter or stroller tubes once their Ø is published or scanned.

bar Ø  ring OD  ears across (mm)  screw  screw and nut
Ø22.2  30.2  12  M4, Ø4.5 clearance  M4 × 16 + M4 nut
Ø23.8  31.8  12  M4, Ø4.5 clearance  M4 × 16 + M4 nut
Ø25.4  33.4  12  M4, Ø4.5 clearance  M4 × 16 + M4 nut
Ø26.0  34  12  M4, Ø4.5 clearance  M4 × 16 + M4 nut
Ø31.8  39.8  14  M5, Ø5.5 clearance  M5 × 20 + M5 nut
Ø35.0  43  14  M5, Ø5.5 clearance  M5 × 20 + M5 nut

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Sheldon Brown (Harris Cyclery): Handlebar and stem dimension crib sheet: clamp and grip diameters — web — reference [verify license at link] — https://www.sheldonbrown.com/cribsheet-handlebars.html
- BikeGremlin: Bicycle handlebar dimension standards: clamp 22.2 to 35 mm, grip 22.2 / 23.8 mm — web — reference [verify license at link] — https://bike.bikegremlin.com/3784/bicycle-handlebar-dimension-standards/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 6 parts): https://xemstudio.com/files/hardware/handlebar-clamp-rings/index.json
API: https://xemstudio.com/api/geometry?object=handlebar-clamp-rings