1/4" Socket Set

A 1/4-drive socket set is the right starting point for a home bike shop. The drive size is matched to the torque range that dominates bike work (single digits to about 25 Nm), the ratchet body is small enough to maneuver around brake calipers and derailleur cages, and a full metric set fits in a tray small enough to share bench space with the wrench you actually need next.

The 188BI6P15 packs the essentials into an SOS foam tray: a 40-tooth 1/4-drive ratchet, two extensions, a sliding T-handle, and eleven metric sockets covering 4 to 13 mm. Open the tray, the set is there; close it, the set is still there.

What's in the set

• 1/4-drive ratchet (188.1), 40-tooth design, 9° engagement
• 55 mm extension for reaching past obstructions
• 150 mm extension for the deep reaches
• Sliding T-handle for non-ratcheting straight-line torque
• 11 metric sockets: 4, 4.5, 5, 5.5, 6, 7, 8, 9, 10, 11, 13 mm
• Laser-cut SOS foam tray that drops into a workbench drawer

What you can actually do with it

The 4–13 mm range covers every standard external-hex fastener on a modern bike under the pedal-axle torque threshold. That means:

• Derailleur cable-pinch nuts (5 mm)
• Stem and clamp bolts that use hex-head nuts (commonly 8 mm)
• Brake-caliper mount nuts (10 mm)
• Some quick-release axle nuts (15 mm needs a larger socket, but the 13 mm covers many older designs)
• Various small-fastener positions around shifters, dropouts, and accessories

The 40-tooth ratchet engages every 9°, which is the fine pitch you want when you're working in a constrained space where the ratchet handle can only swing a small arc.

When you'll outgrow it

The 1/4-drive ceiling is around 25 Nm. For higher-torque work (cassette lockrings at 40 Nm, crank arm bolts at 50 Nm, pedal axles at 35–40 Nm) you need 3/8-drive or 1/2-drive. The 1/4 set isn't a complete bike-shop solution; it's the right foundation, and the high-torque tools layer on top.

Specs

• Drive size: 1/4 inch
• Ratchet engagement: 40-tooth (9°)
• Socket range: 4 mm to 13 mm (11 sizes)
• Extensions: 55 mm and 150 mm
• Storage: SOS laser-cut foam tray

Made in Slovenia, since 1919

Unior has been forging hand tools in Zreče since 1919, and is the official technical partner of multiple World Tour and downhill teams. The socket bodies are forged chrome-vanadium steel; the ratchet pawl and drive square are hardened through, not just surface-treated, which is the metallurgy that lets a small 1/4-drive ratchet survive years of cycle work. The 40-tooth pawl is a deliberate choice over 24- or 36-tooth designs; finer engagement matters more in a constrained bike workspace than rough engagement does in an automotive bay.

Pro tip from our mechanics

The foam tray is half the value of the set. Buying the same 10 mm socket three times because it keeps disappearing is a universal home-shop experience that this avoids. For the broader bit and socket framework: Sockets and bits for bike work →.