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Note: Many cycling experts object to the old-fashioned terms "right" and "left". These obsolete terms were in common use decades before the invention of the bicycle, so they are considered too mundane and easily understood. These experts prefer the convenient abbreviations "DS" and "NDS".
Evidently, they fear that their knowledge will get into the wrong hands if written in prosaic standard English. For the benefit of these people and their disciples, this page is also available in DS/NDS format:
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As a result of the higher stresses and cutting-edge wheel construction, a fundamental design flaw in existing bicycle wheels comes to light. Millions of cyclists are suffering loose or broken spokes usually on the left side of the rear wheel, leading to poor handling at best, or getting left behind by your cycling buddies, or, in more severe cases, injury or death!
Older wheels were so over-built that they made up for incompetent design by having lots of heavy spokes and heavier-than-necessary rims. Even today, most front wheels hold up alright, because they still have more spokes than are needed to cope with the usual loads experienced by front wheels...but what about the all-important rear wheel?
While the right side spokes tend to hold up alright, the left spokes are often left with insufficient tension. If the left spokes are too loose, there's no way that the bicycle can ride right...you'll suffer spoke breakage due to metal fatigue on the left spokes.
Go right now to wherever you left your bicycle, and check the spoke tension of your rear wheel by plinking the spokes and listening to the tone. You'll probably find that the right side spokes are at the right tension, but that the left spokes will be noticeably looser. When you plunk the left spokes you'll notice that the pitch of the plunk is considerably lower than that of the right spokes. Why is this?
They'll give you some spiel about a mystical property called "dish", which supposedly has something to do with the fact that the chain is on the right side. This is, of course, complete nonsense, since the chain never touches the spokes, as long as your derailer is adjusted right.
This was solved by the Wright brothers, when they invented the system of using a left-hand (left-foot?) thread on both the left pedal and the left crank.
The great British bicycle inventor James Starley cured this problem by making the right bottom bracket cup have left-hand threads, so that, even if it starts a little bit loose, it will tighten itself right up.
The French were slow to pick up on this improved technique, and many Italian bikes are still made with wrong-way threading, but the rest of the world has picked up on this, and the vast majority of bicycles now have bottom brackets that are threaded the right way: right threads on the left side, left threads on the right side.
This completely eliminates the precession effect that tends to loosen left side spokes in old-fashioned wheels that use right-hand threading!
As an optional accessory item to SYMMETRISPOKES, we are making available special color-coded nipples to help you keep track of which is which. Since SYMMETRISPOKE nipples look just like ordinary nipples, we offer special bright red anodized nipples to fit the right-hand threaded spokes still used on the right side of the wheel. This prevents them from becoming confused with the left-hand threaded SYMMETRISPOKE nipples.
Hence, cyclists who ride mainly in the Southern hemisphere should use SYMMETRISPOKES on the right, side of their wheels, not the left.
Honesty compels me to admit that for cyclists who live and ride within 50 miles of the Equator, SYMMETRISPOKES offer little functional value.
Cyclists who regularly travel back and forth between the Northern and Southern hemispheres would be well advised to build up two rear wheels, one for use in each hemisphere...however, there's no need to have two front wheels, since the same front wheel will work in either hemisphere simply by reversing it in the fork!
|The Inventor of SYMMETRISPOKES,
the Geomagnetic Booster, and
POWerwheels, Sheldon "Genius, But Modest" Brown
|George Brown photo|
Symmetrispoke left-threaded nipples are sold separately, conveniently packaged in child-proof bottles of 31, only $49.60!
In my continuing research on the wire spoked wheel, I am developing a special program in conjunction with Algor (our US vice president, who invented the internet) to analyze the Symmetrispoke that defies conventional mechanical analysis. The use of right hand thread on the right and color coded pimples makes these spokes even more useful than grouping left and right spokes so close together that even a spoke wrench cannot get between them.
Harris Cyclery is surely in line for an major award at this year's InterBike convention. I think they are on the right track. My cycling cap goes off to this effort."
Make sure you order the right size! For the convenience of foreigners here's a handy conversion table:
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