Double Sided Spoke Wrench 4.0mm x 4.4mm

The 4.0 mm and 4.4 mm nipple sizes show up most often on MTB wheelsets, heavier-rim road builds, and tandems; wheels where the spoke load is high enough that the manufacturer specs a larger nipple body. The double-sided 4.0 x 4.4 mm wrench covers both sizes from a single combination-wrench-style tool body.

A workshop servicing MTB or tandem wheels often runs into both sizes within the same build session: a wheel with 4.0 mm nipples on one bike, 4.4 mm on the next, and a single tool that covers both means fewer wrench-swaps mid-session. The four-flat engagement on both sides protects the nipple flats from rounding; the combination-wrench form factor is the workshop-economy choice.

We carry three configurations of double-sided wrench: this 4.0/4.4 mm variant for MTB and heavier road builds, the 3.3/3.45 mm 1633/2P for the most common road and gravel nipple sizes, and the 4.3/4.4 mm variant for builds at the upper end of the standard MTB range. Pair the 4.0/4.4 mm with the 3.3/3.45 mm to cover most of the modern wheel range from two tools.

Compatibility

• Nipple sizes: 4.0 mm (one side), 4.4 mm (other side).
• Engagement: four-flat on both sides.
• Wheels: MTB wheelsets, tandem wheels, heavier-rim road and gravel builds.

Specs

• Two nipple sizes on a single combination-wrench-style body.
• Plastic-dipped handle for grip.
• Companion sizes: 3.3 x 3.45 mm and 4.3 x 4.4 mm.

Built in Zreče, Slovenia

Unior has been forging hand tools in Zreče since 1919, and sponsors professional road and mountain-bike race teams. The double-sided wrench line is the workshop-economy approach: smart configurations of multiple sizes on a single body, where the alternative would be a parts drawer of dedicated single-size tools. Smart workshop choices like this are part of why the Unior wheelbuilding line shows up in event-mechanic kits where space and weight matter.

Pro tip from our mechanics

Color-mark or tape one end of the wrench at the start of a build so you can grab the correct size mid-rotation without thinking. The two sizes are close enough (4.0 and 4.4) that a quick glance won't reliably tell them apart; a colored tape band on the 4.0 end removes the guesswork. The full wheel-truing workflow is in How to true a bike wheel →