Tool · Mounts
Handlebar size finder
A handlebar size chart by maker range: pick the diameter you measured to see which mounts and lights list it, which do not, and the shims and adapters they name.
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Short answer
Measure your bar or stem where the clamp will sit, then pick that diameter below. Its page lists the mounts and lights whose makers state a range that includes it, the ones whose ranges leave it out, and the shims and adapters those makers list. A range is the maker's statement, not a guarantee for every bar shape.
- 22.2 mm
- 25.4 mm
- 31.8 mm
- 35 mm
- Flat stems, aero and non-round bars
Choose your handlebar size to see the key facts and what fits. Each fact links to its source on the full page.
All handlebar sizes
What each size page shows
| Handlebar size | Mounts whose maker range includes it | Mounts that do not list it | Shims, straps and adapters | Devices and lights |
|---|---|---|---|---|
| 22.2 mm | CatEye H-34N headlight bracket (22-35 mm); Knog Blinder 1400 bar mount (22.2-35 mm, the bottom of its range); SP Connect Universal Bike Mount (about 20-44 mm). | Quad Lock's Handlebar/Stem Mount is designed for 25-40 mm. Wahoo's BOLT 3 / ROAM 3 out-front mount is for 31.8 mm round bars. | Quad Lock secures its Handlebar/Stem Mount with supplied rubber O-rings and nylon zip ties, and says the zip ties can fit most tubes outside 25-40 mm. SP Connect includes one flat and one round diameter adapter. | CatEye lists the H-34N for its AMPP, GVOLT, Sync Core, GE100 and HL-EL160/135 lights, but not AMPP models with rubber strap mounts. Knog's Blinder 1400 clamps with its own mount. |
| 25.4 mm | Quad Lock Handlebar/Stem Mount (25-40 mm, near the bottom of its range); SP Connect Universal Bike Mount (about 20-44 mm); CatEye H-34N headlight bracket (22-35 mm); Knog Blinder 1400 bar mount (22.2-35 mm). | Wahoo's BOLT 3 / ROAM 3 out-front mount is for 31.8 mm round bars. | Quad Lock supplies 2 small and 2 large rubber O-rings and nylon zip ties with the Handlebar/Stem Mount. SP Connect includes one flat and one round diameter adapter. | Quad Lock says the Handlebar/Stem Mount works with all Quad Lock cases and Universal Adaptors. CatEye lists the H-34N for its AMPP, GVOLT, Sync Core, GE100 and HL-EL160/135 lights. |
| 31.8 mm | Wahoo BOLT 3 / ROAM 3 out-front mount (31.8 mm round bars); Quad Lock Handlebar/Stem Mount (25-40 mm); SP Connect Universal Bike Mount (about 20-44 mm); CatEye H-34N headlight bracket (22-35 mm); Knog Blinder 1400 bar mount (22.2-35 mm). | Not confirmed | Quad Lock supplies rubber O-rings and nylon zip ties with the Handlebar/Stem Mount. SP Connect includes one flat and one round diameter adapter. | Wahoo's out-front mount takes the BOLT 3 and ROAM 3; legacy flanged BOLT and ROAM units do not fit it. Wahoo says its ELEMNT, BOLT and ROAM computers do not work directly with Garmin mounts. |
| 35 mm | CatEye H-34N headlight bracket (22-35 mm, top of range); Knog Blinder 1400 bar mount (22.2-35 mm, top of range); Quad Lock Handlebar/Stem Mount (25-40 mm); SP Connect Universal Bike Mount (about 20-44 mm). | Wahoo's BOLT 3 / ROAM 3 out-front mount is for 31.8 mm round bars. | Quad Lock supplies 2 small and 2 large rubber O-rings and nylon zip ties with the Handlebar/Stem Mount. SP Connect includes one flat and one round diameter adapter. | CatEye lists the H-34N for its AMPP, GVOLT, Sync Core, GE100 and HL-EL160/135 lights. Knog includes a GoPro-style mount with the Blinder 1400 as well as its bar mount. |
| Flat stems, aero and non-round bars | Quad Lock sells a Flat Bar Adaptor separately for mounting its Handlebar/Stem Mount on flat stems. SP Connect includes one flat and one round adapter with its Universal Bike Mount. | Wahoo's BOLT 3 / ROAM 3 out-front mount is for 31.8 mm round bars. | Quad Lock says the zip ties supplied with its Handlebar/Stem Mount can fit most tubes outside its 25-40 mm range. | Quad Lock says its Handlebar/Stem Mount works with all Quad Lock cases and Universal Adaptors. Peak Design's Out Front Bike Mount V2 holds the phone with its SlimLink magnetic and mechanical system. |
Where the ranges come from
Every range is the mount or light maker's own, read on 2026-10-14:
- Quad Lock designs its Handlebar/Stem Mount for bar or stem diameters from 25 to 40 mm.[1]
- SP Connect lists tool-free attachment of its bike mount to bars or stems of about 20-44 mm, with one flat and one round adapter included.[2]
- CatEye lists its H-34N headlight bracket for 22-35 mm handlebars.[3]
- Knog lists a 22.2-35 mm bar mount for the Blinder 1400.[4]
- Wahoo's out-front mount for the BOLT 3 and ROAM 3 is for 31.8 mm round bars.[5]
A range assumes a round tube in that span. Quad Lock says its zip ties can fit most tubes outside its range,[1] and we do not turn that into a promise for any particular bar. Flat stems, aero bars and other non-round shapes have their own page. Where a maker states no range, the field reads "Not confirmed".
Next
- How to measure your handlebar diameter for a light or phone mount
- Bike phone mounts: Quad Lock, Peak Design and SP Connect fit
- Bike mounts: bar diameter, interface and the devices makers list
- 22.2 mm
- 25.4 mm
- 31.8 mm
- 35 mm
- Flat stems, aero and non-round bars
Choose your handlebar size to see the key facts and what fits. Each fact links to its source on the full page.
All handlebar sizes
Questions
Which mounts fit a 22.2 mm bar?
Check each maker's range. CatEye lists its H-34N bracket for 22-35 mm bars and Knog lists 22.2-35 mm for the Blinder 1400, while Quad Lock's Handlebar/Stem Mount starts at 25 mm. Open the 22.2 mm page for the full list.[3][4][1]
Does a mount's range guarantee fit?
No. A range is the maker's statement for round tubes in that span. Quad Lock says its zip ties fit most tubes outside its 25-40 mm range, which is not a promise for any particular bar shape.[1]
Why is my 35 mm bar outside some mounts?
Because those makers do not list it. Wahoo's out-front mount for the BOLT 3 and ROAM 3 is for 31.8 mm round bars only.[5]