The Hydra Post is an alternative to suspension forks in smoothing rides over un-even terrain. The mast holding the seat "floats" on a sealed oil chamber, with an adjustable steel spring beneath the oil chamber to provide adjustments for different rider styles and weights. The Hydra Post uses a head system that we have seen on Taiwan made Kalloy seatposts. It is, frankly, a copy of the Shimano XT head system. The head piece is made of cast aluminum with its upper cradle surface knurled to inter-mesh with the bottom of the lower clamp piece. The cradle has an oval slot milled through it for the fastening bolt. The clamp pieces are cast of aluminum and provide nearly 1 1/2" of saddle rail contact at each side. The lower clamp piece is cast with a bottom contoured to the top of the cradle on the head piece. It is also knurled to add grip between the two pieces. A hole through the middle allows the fastening bolt to pass up and anchor into the upper clamp piece. The upper clamp piece has an extension that fits into a hole in the lower piece, this extension has threads tapped into it for the fastening bolt. The bolt is made of steel, has a 6mm hex head fitting, is 36mm long with 8mm by 1.25mm thread pitch. The Hydra Post has this aluminum head fastened to a 9/16" diameter steel rod. The rod extends for an inch and a half passing through a sealed steel collar that closes off the sealed oil chamber that cushions the saddle and rider. The oil chamber is itself cushioned over a steel spring that is adjustable using a variable rate screw adjustment at the very bottom of the seatpost. For a stiffer ride the adjuster is turned counter (or "anti") clockwise. The entire cushion assembly is contained inside aBlack steel tube that becomes the basic tubing section. The diameter of this basic tubing section is 25.4mm. This basic diameter is "built" out to many other diameters by including a "split" aluminum collar or "shim," which slides up the post before insertion to add thickness. The head, tubing section and clamp pieces are wet painted glossy Black. With the clamp perpendicular to the tubing section, the center of rail to end of tube length is 377mm. The weight of a 27.2mm Hydra Post Mountain post is 752 grams. The Hydrapost was first seen in 1991, then was un-available for well over a year as KEI (Knapp Engineering, Inc.) was looking for a way to manufacture them affordably. There had been a discussion of a German company buying the technology, but the Taiwan manufacturer Kalloy is known to have built the head piece. We have heard Kalloy manufactures the entire post. Even with the apparent increase in weight over other posts, it is considerably lighter, and easier than either a fork or a stem change. The Hydra Post is available through us in 26.0mm, 26.2mm, 26.4mm, 26.6mm, 26.8mm, 27.0mm, 27.2mm, 28.6mm, 29.4mm, 30.4mm and 31.6mm sizes.
Size-60-62-64-66-68-70-72-86-94-04-16 $ Price in Catalog
