Just like clutching and jetting, manufacturers work hard to come up with the right chaincase calibration to suit most snowmobiles and their riders, but they can’t meet the needs of every rider. This is why you might want to experiment with different chaincase sprockets in your snowmobile.
Looking for more top-end speed? A lower gear ratio will provide it, but low-end grunt might suffer. On the flip side, a higher gear ratio in the chaincase will reduce top-end speed but provide quicker acceleration.
A ratio change can be obtained by replacing the top, bottom or both chaincase sprockets. Keep in mind that these changes will affect chain wrap — the amount a chain wraps around the tensioner and sprocket. Less wrap offers the least amount of rolling resistance and wear.
Some experts believe in using the smallest gears as possible to reduce rotating mass, while others call for larger gears for their big circumference that makes the chain “bend” more gradually for less resistance inside the chaincase.
To determine a gear ratio, divide the number of teeth on the bottom gear by the number teeth on the top gear. For example, a 41-tooth bottom gear divided by a 22-tooth bottom gear has a 1.86 gear ratio.