 # Gearing Spec

435 Views 8 Replies 5 Participants Last post by  Lakelandsledder Hi Guys;

If my mach 1 670 is 26/44 stock, and I gear down to 25/44, what is the difference between
25/44 and 26/43. Im going for acceleration to 95mph all things equal.

Thanks,

D
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26/43=1.65 26/44=1.69 25/44=1.76
The difference in top speed between 26/44 and 25/44 is about 5 mph, at least in theory.

The difference in top speeds between 26/43 and 25/44 is about 7.5 mph.

This is theoretical top speeds. That's assuming you're somewhere where air temp is -20 degrees F and riding on a frictionless surface.

Probably in reality with your sled, 25/44 will give you the highest top speed of those three ratios. Unless you weigh about 100 lbs.

If you want that 670 to top out at about 95 and get there yesterday, you should be looking at changing to somewhere around 21 or 22/44. Speed Calculations:

Engine Speed ________(rpm) x Gear Ratio __________=________ (rpm) Drive Shaft Speed

Drive Shaft Speed (rpm) x Driver Circumference _________(in) = _________(in/min) Distance Travelled

Now convert inches per minute to miles per hour:

Distance Travelled __________(in/mill) / 12 (in/ft) = _______(ft/min)

Distance Travelled ____________(ft/min) x 60 (min/hour) = ___________(ft/hr)

Distance Travelled ____________(ft/hr) / 5280 (ft/mile) = _____________(mph)

7 tooth 2.52 pitch drivers = 17.64 inch circumference

8 tooth 2.52 pitch drivers = 20.16 inch circumference
9 tooth 2.52 pitch drivers = 22.68 inch circumference
10 tooth 2.52 pitch drivers = 25.20 inch circumference

7 tooth 3" pitch drivers = 21 inch circumference

8 tooth 3" pitch drivers = 24 inch circumference

9 tooth 3" pitch drivers = 27 inch circumference

10 tooth 3" pitch drivers = 30 inch circumference

Example[/u]
Engine Speed 8000 (rpm) x Gear Ratio .5122 (21/41)= 4.097.6 (rpm) Drive Shaft Speed

Drive Shaft Speed 4.0976 (rpm) x Driver Circumference 22.68 (in) = 92.933.568 (in/rnin) Distance Travelled

Now convert inches per minute to miles per hour:

Distance Travelled 92.933.568 ("m/min) / 12 ("m/ft) = 7.744.464 (ft/min)

Distance Travelled 7.744.464 (ft/min) x 60 (min/hour) = 464.667.84 (ft/hr)

Distance Travelled 464.667.84 (ft/hr) / 5280 (ft/mile) = 88.005 (mph)

Try this calculation!!!
FRank
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Don't forget, Ski-Doo also has a overdrive ratio of .83 to 1. So,

88.005 mph / .83 = 106.03 mph
I'm confused. 2
I'm confused.
X=Y-C
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Its not to confusing, find your gear ratio mine is 26/43 divide 26 divided by 43, find your driver Circumference then do the math, mine works out to 101.2 miles an hour for a 01 MXZ 800
Ok, got it. Now for the real question. How fast does a certain gear ratio get to that speed? According to the math a stock 25/43 on a 2002 700 will top out at about 99 MPH. My current 23/43 will top out at 92 MPH. I have been told and can feel the pull of the 23 gear vs. the 25 gear.
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