A Sprocket is different from a gear, in that a gears teeth mesh with other gears, where a sprockets teeth mesh with a chain or belt, and never other teeth directly.

In the case of bicycles, it is possible to modify the overall gear ratio of the chain drive by varying the diameter (and therefore, the tooth count) of the sprockets on each side of the chain. Changing the sprockets on a BMX can change the characteristics of acceleration and top speed by modifying the final drive gear ratio. The standard gear ratio has been 44-16 since BMX was invented. While 44-16 seems crazy these days, its the same gear ratio most riders use, but with smaller sprockets. Making the Front sprocket bigger, make is harder to accelerate, but a higher top speed. Making the Rear sprocket (cog, driver, etc) Smaller does the same thing. If you reduce Both at the same rate, your gear ratio remains the same, while reducing weight, chain links needed, and ground clearance. Until the one piece driver, the smallest gear ratio possible was 33-12. The first one piece driver was Odysseys 11t driver. That was the smallest you could go with good quality bearings and have a dependable drive train. This past year Odyssey has finally brought that down to a 9t (see page 20) with the use of needle bearings. Now you can have a 9t you can depend on, instead of constantly blowing out ball bearings.

While the 44-16 can be directly achieved down to a 25-9, many riders have chosen to “gear-up” which means higher top speeds and help during roll backs. If you look at two of the most high speed riders out there, Gary Young and Chase Hawk, they are both geared up, sometimes more than one step. One step up from a 25-9 would be 27 or 28-9 which is what Gary uses. Two steps up would be 30 or 31-9 which is Chase regularly uses.

Some of the 2010 Odyssey sprockets have a new teeth profile design, called Incisors. This will be a running change throughout all the sprockets. The Incisor teeth have a new profile that help engage the chain in a much better fashion. While the teeth seem like a generic instrument, the engagement between the chain and sprocket it’s the most important function. The chain feeding on to the sprocket is improved, and contact with the chainlinks is improved.

Its all the small things added up that create a machine that is greater than the sum of its pa