Collet for 689/2BI - 689.1/4

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Slide-hammer bearing collets wear out. The expanding fingers that grip the bearing's inner race during a pull are doing the loaded work on every stroke, and after enough years on a shop bench the spring action softens or one of the fingers takes a permanent set. A worn collet that doesn't expand fully no longer grips the inner race, the slide hammer carries air, and the bearing stays put. The 689.1/4 is the replacement set that brings a 689/2BI-US Inner Bearing Puller back to factory grip. How it works The 689.1/4 is the same six-collet set that ships with the original puller kit. Each collet is chrome-vanadium steel, ground to fit a specific inner-diameter band: 6.5 – 8 mm 10 – 12 mm 12 – 15 mm 17 – 20 mm 22 – 28 mm 30 – 36 mm The two ends of the size range get the most use (the 12 – 15 and 17 – 20 collets carry the bulk of road and MTB hub work, and the 22 – 28 carries most BB bearing work) and are the ones we see wear first. When to replace Three signs a collet is at end of life: The collet doesn't expand fully when the shaft is drawn back. The fingers stay close to the centerline and the collet drops through the bearing without engaging. The collet expands but doesn't hold. It engages on insertion, then slips off the inner race when the slide hammer comes up. Usually a sign that one of the fingers has taken a permanent outward set and isn't returning to the loaded position under spring force. A finger has cracked. Rare, but it happens on collets that have lived through a long career of impact loads on aluminum-shelled hubs where the bearing fused into the shell. Buying the full replacement set rather than chasing single sizes is the right call most of the time. The wear pattern that lifts one collet out of spec usually means the rest are close behind. Compatibility The 689.1/4 fits any 689/2BI-US Inner Bearing Puller, current generation or older. Every 689/2BI-US built since the line launched takes the same 689.1/4 set, so a replacement set retrofits a tool that's been at the bench for a decade. Built in Zreče, Slovenia Unior has been forging hand tools in Zreče since 1919, and sponsors professional road and mountain-bike race teams. These are the same collets that ship in the original 689/2BI-US kit, made from the same chrome-vanadium steel and ground to the same dimensional spec. You won't tell a replacement set from the original ones unless you compare their wear patterns side by side. Pro tip from our mechanics A collet that's started slipping is also a collet that's been carrying stress that probably told you something else was wrong. We check the shaft for play and the slide hammer's weld for fatigue cracks at the same time we replace the collet set. The collets are a wear part, but they're rarely the only thing wearing on a tool that's been at the bench long enough to need them. The bigger picture is at Bearing and headset service: a workshop guide → Show more