Valve Core Tool

The valve core is the part most home mechanics never think about until they're stuck. A slow leak that isn't a puncture is usually a valve-core seal that's hardened, dirty, or torn; replacement cores are pennies and the swap takes thirty seconds. The 1755/2 is the workshop tool that does the swap without rounding off the core's slot.

A good number of valve core tools are made of aluminum because aluminum is soft and cheap to machine. Aluminum is also what rounds off after a few hundred swaps; the slot opens up, the core spins inside the tool, and the swap goes from thirty seconds to several minutes of fiddling. The 1755/2 is tool steel rather than aluminum, which is the property that determines whether the tool lasts for one season or for a working life. Both ends of the tool are slotted: one for Presta valve cores, the other for Schrader. A single tool covers the whole shop, road through MTB through commuter.

The size sits in the hand. About 80 mm long and 10 mm in diameter; small enough to slip into the bottom of a workbench drawer without disappearing, large enough to feel right in a mechanic's hand under load. Not so small that it gets lost; not so large that it can't reach inside a deep-section road rim. The diameter is the detail that makes it a workshop tool rather than a trail tool; a thicker shaft transmits torque without flex, which is what stops the slot from rounding off in the first place.

Specs

• Length: ~80 mm
• Diameter: ~10 mm
• Material: Tool steel
• Dual-end slotted (Presta + Schrader)
• SKU 1755/2

Built in Zreče, Slovenia

Unior has been forging hand tools in Zreče since 1919, and is the official technical partner of multiple World Tour and downhill teams. Tool steel is what separates a workshop valve core tool from a trail one; the same material decision that lands hardened steel in chain pins and plier jaws lands it in this slot. The tool steel and the thickness together are what make the 1755/2 a “the only reason you'll ever replace it is if you lose it” tool. For the trail version that fits inside a multitool kit, the Valve Core Tool / Handle 1700VH does the same job at smaller scale; the 1755/2 is the workshop counterpart.

Pro tip from our mechanics

A slow leak that doesn't trace to a puncture is almost always a valve core, and on tubeless setups specifically, it's almost always a core that's been gummed by sealant added with the core still in place. The correct tubeless-sealant sequence is to remove the core with the 1755/2 first, add sealant through the valve, then reseat the core; sealant added through the open valve while the core is in place coats the core's seal and turns it into a slow-leak generator. Our How to remove and install a bike tire → walks through the tubeless-sealant-through-the-valve-core-out sequence as part of the broader install workflow.