[DC.chief]

Originally Posted by permachief

I don't have gearing change experience with bigger bikes like yours but have done gearing changes on smaller (250cc) dirt and dualsport bikes.

If you want to gear the bike higher you would put a smaller sprocket on the rear and/or a larger sprocket on the front.

A 1 tooth change on the front typically is equal to about a 3 tooth change on the rear sprocket.

You calculate the final drive ratio by dividing the rear number by the front number (i.e., 43/14=3.07, 43/15=2.86, 40/14=2.85, etc.) The lower the result, the higher the gearing (I know, its sounds backwards).

The percentage change in the final drive ratio will have the same percentage effect on rpm/mph ratio. For example, changing the final drive ratio from 3.07 to 2.86 is gearing the bike 7.34% higher (3.07/2.86=1.073426). Therefore, assuming that 5,500 rpm in 5th gear previously produced 65 mph, the new gearing will now produce approximately 70 mph in 5th gear at 5,500 rpm (65x1.0734=69.77). (Note: This also assumes that the engine has the needed torque to actually pull the higher gearing which may not always be the case especially in smaller cc bikes.)

With the bikes I have experience on, you can typically change the front sprocket +/- one tooth without lengthening or shortening the chain. A change of +/- three teeth on the rear may require a chain length adjustment (it just depends on how much adjustment span is available on the swing arm where the rear wheel is mounted.) So typically, the front sprocket is the preferred sprocket for a gearing change initially (and front sprockets are typically cheaper than rear sprockets).

Getting your bike properly geared for your specific use is definitely worth it. It will only increase your enjoyment of the bike.

well done sir