Hsin Lung, (pronounced Sin Lun), is a Taiwan maker of generally well made in-expensive bike parts, primarily stems and handlebars, that are used throughout the bike industry as original parts on many, many popular brands of bikes sold around the world. Hsin Lung, however has never been able to crack the aftermarket replacement parts market, because their name was too strange and difficult to pronounce, and many of the people who used their parts, didn't want the public at large to know that a Taiwan factory was responsible for what they had been passing off as their innovation. Hsin Lung's trademark is a stylized HL mark and you are likely to see it on any stem expander bolt wedge, on any stem made "in the USA". HL has gotten around the aftermarket problem by introducing their better goods under a new brand name world wide called "ZOOM".
The ZOOM post is Hsin Lung entrance into after market seatpost sales. The post draws on their experience in stem building because of how the clamp is cinched. The post is largely made of Cro-moly steel, with infinitely adjustable, revolving, aluminum clamp pieces. The vertical tubing section is made of either Satin Silver, or Titanium Grey colored, 0.9mm thick, Cro-moly steel, that has the top swaged to a narrower diameter as it curves slightly backward. The top of the tubing section is miter cut for a stem-like binder tube. The binder is made of the same steel, with machined knurls rolling around it's entire interior, and is TIG welded with fine pulsed welds, perpendicular, across the top of the tubing section. On the underside, at the base of the binder tube, the tubing section is drilled for a machined Cro-moly rod to be inserted. The rod has been drilled, and threaded to fit a recessed head pinch bolt, (this is where the stem experience exists).
The rod is TIG welded into the tubing section, and to the binder tube, then the pinch rod and binder tube are cut through to make the binder tube compress and cinch. The clamp pieces are machined from a 5.7mm thick aluminum extrusion. The upper and lower clamp pieces are only slightly different, and give four points of upper and lower contact to the saddle rails. The binder bolt is made of Chrome plated steel, threaded with 8mm by 1.25mm thread pitch, that is 20mm long. The bottom of the tubing section is not square cut, like all other seatposts, it is diagonally cut like the bottom of a stem quill tube. The sharp diagonal cut reduces useful length in the post a significant amount, because clamping it into a frame requires full circumference contact inside the seat tube of the bicycle. Though this post has a manufacturers' nominal length of 300mm we found with clamp perpendicular to the tubing section, the center of rail to end of tube length really to be 260mm. It has been suggested that with this post turned pinch bolt forward it would be useful for Tri-athletic use. The weight of a 27.2mm ZOOM post is 256 grams. The ZOOM post is available in 26.4mm, 26.6mm, 26.8mm, 27.0mm, 27.2mm, and 28.6mm. Satin Silver or Titanium Grey.
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