A headset cup pressed in even slightly off-square wears unevenly for the life of the bike. The lower bearing carries the steering load at the angle the cup defined on install; if the cup went in tilted half a degree, the bearing rolls at half a degree of misalignment forever. The fix happens before the press completes, not after. A press that pulls the cup in straight, with the load spread evenly across the cup's outer face and with the press body's mechanical advantage doing the work instead of a hammer, is the workshop tool that owns this job. The 1680/4 is the press built for it. How it works The 1680/4 is a threaded press. The spindle drops through the head tube, the T-handle flange bears on the cup, and the clamping sleeve takes the reaction at the other end of the tube. Turning the handle draws the assembly together and seats the cup square in the bore, without a hammer. Two features distinguish the 1680 from a bench-vise-and-block-of-wood improvised press: Sized bushings on one spindle. Stepped bushings on the spindle cover 1", 1-1/8", 1-1/4", and 1-1/2" headset cups, so one press handles the sizes that show up on the bench. Clamping sleeve at the reaction end. The official clamping sleeve (1680.5/4) holds the reaction end of the spindle. A longer spindle is specified for BMX headsets with larger tubing; the working span (C) is 320 mm. Spec Size range: 1", 1-1/8", 1-1/4", and 1-1/2" headset cups Mechanism: threaded T-handle press with clamping sleeve (1680.5/4) at the reaction end Build: premium flex plus carbon steel; 410 mm long, 340 mm handle span, 2615 g; Unior lifetime warranty Compatibility The 1680/4 presses 1", 1-1/8", 1-1/4", and 1-1/2" headset cups into head tubes. That covers: 1 inch threaded and threadless headsets (most legacy designs) 1-1/8 inch threadless headsets (current road and gravel standard) 1-1/4 inch headsets (some current road and MTB designs) 1-1/8 inch upper / 1-1/2 inch lower tapered head tubes (the dominant current MTB and gravel design) The press works on press-fit headsets directly. Threaded headsets in the same size range also get pressed by the 1680/4 because the cups themselves are press-fit; the threaded interface is on the steerer side, not the head-tube side. Built in Zreče, Slovenia Unior has been forging hand tools in Zreče since 1919, and sponsors professional road and mountain-bike race teams. The 1680/4 is the dedicated headset-cup press in the line: one spindle covers 1" through 1-1/2" cups, with the extra length Unior specifies for BMX head tubes. The press lives on a shop bench for the working life of the shop. Pro tip from our mechanics Grease the bearing seats lightly before pressing the cups in. A thin film of anti-seize on the head-tube bore makes the cup go in with even effort instead of binding partway through; it also makes the cup come out cleanly years later when service eventually needs to happen. Grease the cup's outer face, not the bearing race; the race needs to stay clean. The full headset workflow, including the install sequence, lives at Bearing and headset service: a workshop guide → FAQ Does the 1680/4 cover a 1-1/2 inch lower cup and a long BMX head tube? Yes. Official coverage is 1", 1-1/8", 1-1/4", and 1-1/2" headset cups pressed into the head tube. Unior also specifies a longer spindle for BMX headsets with larger tubing; the working span (C) is 320 mm. Does an integrated headset need this press? No. Integrated (IS) frames have no pressed cups: the bearings sit in machined cradles inside the head tube. The 1680/4 is for pressed-cup systems, meaning external-cup (EC) and zero-stack (ZS). Threaded and threadless both use pressed cups; the press seats the cup in the head tube, not on the steerer. Can the 1680/4 install a press-fit bottom bracket? Unior's own service manual lists the 1680/4 as one of two tools for installing a cartridge bearing or a press-fit bottom bracket. The other is the 1721 universal bearing press, which the manual calls lighter and easier because its bushings match bearing dimensions. For headset cups, the 1680/4 is the dedicated press. What is the Headset Press made of, and how big is it? Premium flex plus carbon steel. Official dimensions: 410 mm overall (A), 340 mm handle span (B), 320 mm working span (C), 2615 g. Article 1680/4, SKU 616290, covered by Unior's lifetime warranty. Service parts are the bushing (1680.4/2), handle (1680.2), spindle (1680.3/4), and clamping sleeve (1680.5/4).
Related
Related
Related
Related