In 1986-88 there was a fad for equipping mountain bikes with U-brakes mounted underneath the chain stays. This provided a nice clean look to the seat stay area of the bicycle, and provided a somewhat simpler cable routing. In addition, since the chain stays are larger and more rigid than typical seat stays, the "problem" of flexing of the studs under load was reduced. Conventional cantileves cannot be mounted on the chainstays, because the cantilevers would get in the way of the cranks.
Although U-brakes were cool looking and powerful, the fad died quite abruptly when people actually started using the bikes that were sold with chainstay-mounted U-brakes. They had several serious drawbacks:
Install the arms with them at their maximum spread and tighten the bolts that hold them to the frame. This is how you set the springs. Only connnect the transverse cable after this has been done.
There is usually a small setscrew on the side of one of the arms for fine adjustment of spring balance.
Set the transverse cable as short as possible for best braking. Check the brake shoe adjustment frequently--due to the location of the pivot studs on these brakes, as the brake shoes wear they hit higher and higher up on the rims. If you don't keep on top of the adjustment, they will eventually start rubbing on the tire sidewall. Many thousands of tires have been ruined by this.
This was made possible by the development of chains in which the ends of the rivets did not protrude far past the side plates. 7- and 8-speed freewheels are also "Ultra" spaced, but the term is mainly used to describe the narrow 6-speed units.
See also my article on Shimano Cassettes.
|Uniglide ®||Hyperglide ®|
Upright handlebars are sometimes referred to as "mountain bike " handlebars, but that's sloppy usage, because upright handlebars are used on most bikes designed for street use.
The V2 BBs work with FC M752, FC M751, FC M572, FC M571, FC M510-8 and FC M440-8 cranks.
|Schrader valve||Presta valve||Woods valve|
In the case of Presta valves, which have non-removeable, built-in caps, external caps are unnecessary in use. The purpose of these redundant caps that come with Presta tubes and tubulars is so that the pointy end of the valve won't puncture your spare tube or tubular while it is rolled up. There's no reason to use them in actual riding
V-Brakes and other direct-pull cantilevers have more mechanical advantage than other brakes, so they require special hand levers with less-than-average mechanical advantage to keep the overall mechanical advantage in a useful range.
Some V-Brakes also incorporate a parallelogram linkage which mantains the shoe at the correct angle as it approaches the rim. This feature also allows the motion of the shoe to be more nearly horizontal than conventional cantilevers.
"V-Brake" is a Shimano trademark.
In the post WW2 era, most Japanese industries acquired similar governing bodies under the J.I.S.C. (Japanese Industrial Standards Committee). These agencies helped to turn around the international reputation of Japanese products from the former stereotype of cheap copies of western designs to their present high reputation for quality and reliability.
Also, British spelling of "vise ."
This is a tool of last resort for removing nuts or bolts whose heads are so badly damaged that the proper wrench will not fit them. They should not be used on un-damaged fasteners, because their serrated jaws will damage the part they are used on.
|Articles by Sheldon Brown and others|
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