Handlebar size
31.8 mm handlebars: computer, light and phone mounts that list it
31.8 mm is the diameter Wahoo makes its BOLT 3 and ROAM 3 out-front mount for, and it sits inside the Quad Lock, SP Connect, CatEye and Knog ranges.
Also listed as 31.8mm
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Short answer
31.8 mm is the diameter Wahoo makes its BOLT 3 / ROAM 3 out-front mount for, on round bars. It is also inside the ranges Quad Lock (25-40 mm), SP Connect (about 20-44 mm), CatEye's H-34N (22-35 mm) and Knog's Blinder 1400 (22.2-35 mm) list. Measure your bar where the clamp will sit.
Key facts
- How to check yours
- Measure where the clamp will sit, in millimeters, because makers state their fit that way (Wahoo: 31.8 mm round bars). Use a caliper, or wrap a paper strip around the bar, mark the overlap and divide that length by pi (3.14).[1]
- Mounts whose maker range includes it
- 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).[1][2][3][4][5]
- Mounts that do not list it
- Not confirmedEvery mount range we read includes 31.8 mm; Peak Design's range is not stated.
- Shims, straps and adapters
- 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.[2][3]
- Devices and lights
- 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.[1][6]Wahoo's warning that direct use damages the mount interface is stated for the ELEMNT only.
Watch out for
- Wahoo warns that over-torquing its BOLT 3 / ROAM 3 out-front mount can strip its threads.
- Wahoo's out-front mount is for round 31.8 mm bars, not aero or flat shapes.
- Wahoo says its BOLT, ROAM and ELEMNT computers do not work directly with Garmin mounts.
- Legacy flanged BOLT and ROAM units do not fit the BOLT 3 / ROAM 3 out-front mount.
What fits
Product details below are the seller's own description unless a source is shown. Pick the variant named for each item.
Computer mount (Wahoo)
Wahoo ELEMNT ROAM 3 and BOLT 3 out-front mount (31.8 mm)Choose the BOLT 3 / ROAM 3 out-front mount; older flanged units need a different mount.
Wahoo makes it for 31.8 mm round bars and warns that over-torquing can strip its threads.
Computer mount (Garmin)
K-Edge Max XL Combo mount for Garmin, 31.8 mm (computer plus GoPro-style mount below)Choose the 31.8 mm Garmin Combo, not the 35 mm version.
K-Edge lists a 31.8 mm clamp for Garmin computers with a GoPro-style mount below.
Light mount
Magicshine MJ‑6272 aluminium out-front mount (GoPro interface)Choose the MJ-6272 out-front mount.
Magicshine lists it for 31.8-35 mm bars.
Phone mount
SP Connect Universal Bike Mount (phone, 20‑44 mm bars and stems)Choose the Universal Bike Mount (SKU 53342).
SP Connect lists bars or stems of about 20-44 mm.
Front light
Knog Blinder 1400 front light (2nd gen, USB-C)Choose the Blinder 1400 (2nd gen, USB-C); it is the only version listed.
Knog lists a 22.2-35 mm bar mount.
Next: Garmin vs Wahoo computer mounts, how to measure your handlebar and pocket torque tools.
Questions
Will a Wahoo BOLT 3 out-front mount fit my bar?
Wahoo makes it for 31.8 mm round bars. Measure your bar where the mount will sit, and do not over-tighten it: Wahoo warns that over-torquing can strip its threads.[1]
Can I put a Wahoo computer on a Garmin mount?
Wahoo says its ELEMNT, BOLT and ROAM computers do not work directly with Garmin mounts. See Garmin vs Wahoo computer mounts.[6]