As time went on and materials improved, by the 1940s, most bikes converted to 1/2" (12.7 mm) pitch chain, with 1/8" (3.2 mm) thick sprockets. When the first "10 speed" bikes appeared, in the late 1950s, with 5 sprockets in back, chains and sprockets were thinned to 3/32" (2.4 mm) but they stuck to the 1/2" pitch dimension.
In the early 1980s, Shimano tried to introduce a slightly smaller 0.3937 pitch chain (10 mm) but nobody wanted that metric junk, and it really wasn't that much smaller anyway.
That's why Rivendell Bicycles chose Nanodrive for their new flagship Downhill model, shown above.
The Nanodrive MTB system sticks with 9 sprockets in back, 3 in front, because extensive research has proven that this as many as the human brain is capable of comprehending, and not everybody can even do that many.
As you can see on the latest Rivendell downhill model, Nanodrive makes a huge improvement in chainring clearance, allowing the skillful rider to jump even bigger logs without fear of damaging expensive chainrings. In addition, the narrower width of the NanoNine (TM) drivetrain permits wider hub flange spacing and thus increases the bulletproofness of your wheels.
The only parts you need to replace are the rear wheel, the front derailer, the rear derailer, the cassette, the crankset and chainrings, and the shifters! Nothing to it!
Nanodrive is a revolutionary new high performance system, and we do mean system. For correct results you must use all genuine Nanodrive parts, and only genuine Nanodrive parts. You'll find Nanodrive provides the smoothest riding, smoothest shifting you've ever experienced, with a unique combination of stiffness and suppleness, high performance and low weight.
We're sure you'll be delighted with the Nanodrive, and that's why we offer our unique Nano-guarantee!* .
Now there are a couple of problems with a setup like that. First of all, the jumps are too big--look at the huge gap between the 11 and 12! The 12-13 jump isn't much better.
In addition, the gear range is too limited. You really don't want to go any smaller than 11 teeth for smooth pedaling, and only weaklings need a sprocket as big as 21.
This system doesn't have even one gear as high as a 10 Gain Ratio. Now, take a look at a typical "Quarter Twenty" Nanodrive drive setup:
Note that the 106 and 78 tooth chainrings are exactly equivalent to 53 & 39 respectively. The 17 tooth sprocket is equivalent to an 8 1/2 tooth sprocket for old-fashioned 1/2" chain, and the 36 tooth is equivalent to an 18.
In addition to giving much tighter spacing, this gives you 5 whole gears above the pitiful 53/11 top gear on the old system from the last century!
|In Commemoration of
The Inventor of the Nanodrive,
Product W, Carrababy, Tork-Grip Universal Torque Wrench,
Real MAN Saddles, Symmetrispokes, the Geomagnetic Booster, and
POWerwheels, Sheldon "Genius, But Modest" Brown
|Scott Cutshall photo|
|Check Out All These
Fine ShelBroCo Products:
|and these products
from our sponsors:
|Articles by Sheldon Brown and others|