Here is how to gear your bike for your weight, riding style and personal peccadilloes.
NUMBER ONE: GEARING UP OR GEARING DOWN
Don’t confuse gearing up with gearing down. Gearing up, either by using a larger countershaft or smaller rear sprocket, decreases the final drive ratio and adds more speed to the motorcycle. Gearing down, which increases the final ratio and reduces speed, is accomplished by using either a smaller front sprocket or larger rear sprocket.
NUMBER TWO: WHAT IS FINAL DRIVE RATIO?
The final drive ratio can be seen on paper by dividing the number of teeth on the rear sprocket by the number of teeth on the countershaft. The result is the final drive ratio, or in simpler terms, how many times the countershaft will turn in order to turn the rear wheel one revolution. A higher number equals more turns of the countershaft and lower gearing, while a smaller number (ratio) is taller gearing. Lower gearing means the engine speed (revs) will be higher to travel the same speed, and taller gearing lets the engine work slower. Got that?
NUMBER THREE: HEADED FOR MAMMOTH?
Engines produce less power at high altitude and generally need to be geared down (larger rear sprocket) to rev freely.
NUMBER FOUR: CAN IT SAVE YOUR CLUTCH?
With lower gearing, the engine runs freer and is more responsive, so you will use the clutch less.
NUMBER FIVE: WHAT WILL TALLER GEARING DO TO THE POWERBAND?
A tall-geared engine is mellow and controllable, but might require the rider to use more clutch.
NUMBER SIX: WHAT WILL LOWER GEARING DO TO THE POWERBAND?
The engine will move through the spread of the gearbox quicker with lower gearing, but that also means that the rider will be shifting faster and more often. The reverse is true with taller gearing.
NUMBER SEVEN: CARRY A STARTER PACK
By carrying a one-tooth lower countershaft and a one-tooth and two-teeth larger rear sprocket, a rider will be able to easily change gearing at the track without changing chain length (changing one tooth on the counter is the approximate equivalent of three and one-half teeth on the rear sprocket).
NUMBER EIGHT: BABY STEPS WITH GEARING
Never make more than a one tooth change in gearing at a time.
NUMBER NINE: NEW SPROCKETS MEAN NEW CHAIN
Keep in mind that it makes no sense to change to a fresh sprocket if the existing drive system is wasted. Running a new sprocket with a worn chain costs power and instantly wastes the sprocket.
NUMBER TEN: COUNTERSHAFT OR REAR SPROCKET
If you settle on a one-tooth smaller countershaft as your particular hot gearing, it is better to switch back to the standard counter with a three- or four-tooth larger rear sprocket and a new, one-link longer chain (don’t use two master links). Small countershafts are much harder on the chain and increase the rate of wear.
Guest Author: Doug — Motocross Action