Reach BikePro on a 24 hour basis at 803-280-1537 Terry Dunbar is on duty as the technical expert, who also speaks Spanish as well as English and has quantities on hand information. Call her now for any questions about Bike Pro you may have.
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Reach BikePro on a 24 hour basis at 803-280-1537 Terry Dunbar is on duty as the technical expert, who also speaks Spanish as well as English and has quantities on hand information. Call her now for any questions about Bike Pro you may have. |
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Ventana Mountain Stem
This review is for historical purposes only, Ventana doesn't sell their stem other than with one of their frames. The Ventana stem represents the best of hand crafted, high polished aluminum stems. The quill is fabricated from solid aluminum rod that has been drilled through form the top for the expander bolt, and bored, with a deep recess from the top so the expander bolt head sits well into the quill. This is a nice trick, reducing the length, (just 100mm), of the expander bolt, (and thereby the bolt's weight, it weighs only 42 grams). Recessing it this way decreases the length of the stainless steel bolt by one inch. The wedge piece is made of machined aluminum rod and weighs 16 grams. The extension section is made of aluminum tubing and is TIG welded to the quill piece. The handlebar binder tube is made of sturdy aluminum tubing, (with a heat release hole facing into the extension), is cleanly TIG welded to the extension. The binder fittings are made of machined aluminum rod, that is drilled and tapped for the stainless steel binder bolt. The binder tube has been miter cut so the binder fitting piece lays into a recess so that when it is welded to the binder tube there are long joining surfaces for durable weld contact. After welding the fitting on the front of the stem is sawn through creating the binder cinch system. Beneath the extension section, there is a TIG welded aluminum "macaroni" brake cable stop/routing guide. This piece is threaded on the inside for the routing tube, so that it can't dropped or lost in the future. The stem is then heat treated to bring it to T6 ductility. After manufacture the entire stem receives an intensely high polish, using various polishing compounds on a polishing wheel. The finish is so bright that it can be used as a mirror for shaving. This high polished finish is difficult to see in the image of the complete stem, because there is a tendency for high silver colors to "photograph" as a white or pale blue in color, but the detail shots will give you some impression. The Ventana aluminum stem has a 25.4mm diameter binder tube to fit all bulged style mountain handlebars, or 22.2mm bars with a handlebar shim, is available in 125mm, 138mm, or 150mm extension lengths in either a 0 degree or 20 degree rise. It is made only in the 1" diameter. The weight of a 138mm Ventana stem with 0 degree rise is 251 grams. |
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In-depth Information About Metals Aluminum Aluminum is extracted electrolytically from bauxite ore. It is made by the electrolysis of aluminum oxide which is found in larger concentrations within bauxite ore. Bauxite is a mixture of the hydroxides of aluminum, together with other impurities such as oxides of iron, titanium, and silicon. Bauxite is produced by the weathering and change of aluminum silicate rocks usually found in tropical and semitropical regions where climate has produced an accelerated weathering process. Bauxite is not a rare ore and is widely available in the US, the Caribbean, and Europe. Approximately 4 pounds of read the full article... Beryllium Beryllium is a specialty metal that is steel-grey metal in color, with an extremely low density, making it very light weight. At 1.85 grams to the cubic centimeter, its density compares to that of magnesium. It is also a high strength metal, making it possible to design light weight, thin membered parts with ahigh stiffness. A column made of beryllium to support a load placed directly downward on top of it, will have a greater load carrying capacity, and be lower in weight than any other metal of equal size. Until the 1950's beryllium was used read the full article... Titanium The element titanium was discovered in 1763 by an English cleric, William Gregor who was an amateur chemist with an inquiring mind. It was in the black sands of Cornwall that he discovered the new element that had up to that time, attracted little scientific interest. A few years later, an Austrian, Klaproth, extracted the same element from an ore widely known as "rutile", which is a mineral consisting of titanium dioxide (one titanium atom, two oxygen atoms), that is a reddish-brown substance with a slight metallic luster. While rutile is the highest grade read the full article... Metallurgic Hardness Testing There are three types of tests used with accuracy by the metals industry,they are the Brinell hardness test, the Rockwell hardness test, and the Vickers hardness test. Hardness is the property of a metal which gives it the ability to resist being permanently deformed (bent, broken, or have its shape changed), when a load is applied. The greater the hardness of the metal, the greater resistance it has to deformation. Since the definitions of metallurgic ultimate strength and hardness are rather similar, it can generally be assumed read the full article... |
