Gear ratio check
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| − | + | ==Overview== | |
| − | + | Methods to determine the gear ratio of the differential | |
| − | =Methods to determine the gear ratio of the differential | + | |
==Counting the teeth on ring and pinion== | ==Counting the teeth on ring and pinion== | ||
| + | If there is a removable cover on the differential, removing it and counting the teeth on the gears is the most reliable method. On some ring gears, there will be a pair of numbers stamped into the outer circumference that will be the tooth count. It may look like 41:10 or 41-10, etc. It the ring gear isn't stamped, count the teeth on the ring gear and the pinion gear, then divide the ring gear tooth number by the pinion tooth number to find the ratio. | ||
| + | *For example: | ||
| − | + | 41 divided by 10 = a 4.10 ratio | |
| + | 40 divided by 13 = 3.08 | ||
==Rotating the tires method== | ==Rotating the tires method== | ||
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With a standard open (non posi traction) differential raise one wheel off of the ground, mark the tire at the 6:00 position, mark the drive shaft. Turn the tire exactly 2 full turns. Count the number of times that the drive shaft turns. | With a standard open (non posi traction) differential raise one wheel off of the ground, mark the tire at the 6:00 position, mark the drive shaft. Turn the tire exactly 2 full turns. Count the number of times that the drive shaft turns. | ||
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==Optional methods== | ==Optional methods== | ||
| − | ;First | + | ;First method: |
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'''1.''' Drive the vehicle at a steady speed. Note the RPM. | '''1.''' Drive the vehicle at a steady speed. Note the RPM. | ||
::For example, if the vehicle is driven at 50 mph, and at that speed the tachometer reads 2,000 RPM, record that the engine speed was 2,000 RPM at 50 mph. | ::For example, if the vehicle is driven at 50 mph, and at that speed the tachometer reads 2,000 RPM, record that the engine speed was 2,000 RPM at 50 mph. | ||
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| − | ; | + | ;Second method: |
| − | Another easy way to estimate the final drive is to use a | + | Another easy way to estimate the final drive ratio is to use a [http://ctny.audiworld.com/mark/s4/gears/gear_calc.html gear ratio calculator]. |
Drive the vehicle at 50 MPH (as an example), note and enter the speed (50 mph), the RPM (what ever you noted), and for the final drive, enter 1 into the calculator. When you hit calculate, the rear gear ratio estimate will come up. | Drive the vehicle at 50 MPH (as an example), note and enter the speed (50 mph), the RPM (what ever you noted), and for the final drive, enter 1 into the calculator. When you hit calculate, the rear gear ratio estimate will come up. | ||
| − | == | + | ==Resources== |
| − | + | [http://ctny.audiworld.com/mark/s4/gears/gear_calc.html Gear ratio calculator] | |
[[Category:Rearend]] | [[Category:Rearend]] | ||
[[Category:Good articles]] | [[Category:Good articles]] | ||
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