bumblebee06
Speed Demon
So after having this question and finding no answer on S197 i though why not add how to do it. What gears do you have? The label on the diff could be gone, they could be aftermarket and you cant tell, or the seller simply forgot. A Few ways to tell here.
Gear Counting
1. Take off the rear differential. To do this jack up the rear end of the car and set it on jack stands (for safety). Take off the cover for the differential. Once off count the teeth on the ring gear. Then count the number of teeth on the pinion gear. Take the ring number and divide the pinion by it to get the gear ratio. Ring/Pinion = Gear Ratio
37/11 = 3.31s
39/11 = 3.55s
41/11 = 3.73s
43/11 = 3.90s
45/11 = 4.10s
47/11 = 4.30s
Drive shaft Method
2. Jack up the rear of the car. Put it on jack stands (for safety). Set the rim level. Put a piece of tape on the tire and another one on the car level with the tape on the tire. Then mark the top center of the drive shaft and rear end with white out or a noticeable marker. Then spin the marked tire until the line of the drive shaft goes back to where it started. Count how many times you spun the wheel and that will give you the gear ratio.
3 1/4 = 3.31s
3 1/2 = 3.55s
3 3/4 = 3.73s
3 4/5 = 3.90s
4 1/5 = 4.10s
4 1/4 = 4.30s
Easiest Method
3. Get in your car. Start It. Buckle up (for safety). Drive to nearest highway. Get up to 60mph in 4th gear or 3rd for autos. Set cruise control to on. Look at your rpms. Note that number. Then take that number and divide it by 795 or whatever your revs per mile are per your tire size. That will give you your gear ratio.
For 235/55/17s
2631 = 3.31s
2822 = 3.55s
2965 = 3.73s
3100 = 3.90s
3259 = 4.10s
3418 = 4.30s
Gear Counting
1. Take off the rear differential. To do this jack up the rear end of the car and set it on jack stands (for safety). Take off the cover for the differential. Once off count the teeth on the ring gear. Then count the number of teeth on the pinion gear. Take the ring number and divide the pinion by it to get the gear ratio. Ring/Pinion = Gear Ratio
37/11 = 3.31s
39/11 = 3.55s
41/11 = 3.73s
43/11 = 3.90s
45/11 = 4.10s
47/11 = 4.30s
Drive shaft Method
2. Jack up the rear of the car. Put it on jack stands (for safety). Set the rim level. Put a piece of tape on the tire and another one on the car level with the tape on the tire. Then mark the top center of the drive shaft and rear end with white out or a noticeable marker. Then spin the marked tire until the line of the drive shaft goes back to where it started. Count how many times you spun the wheel and that will give you the gear ratio.
3 1/4 = 3.31s
3 1/2 = 3.55s
3 3/4 = 3.73s
3 4/5 = 3.90s
4 1/5 = 4.10s
4 1/4 = 4.30s
Easiest Method
3. Get in your car. Start It. Buckle up (for safety). Drive to nearest highway. Get up to 60mph in 4th gear or 3rd for autos. Set cruise control to on. Look at your rpms. Note that number. Then take that number and divide it by 795 or whatever your revs per mile are per your tire size. That will give you your gear ratio.
For 235/55/17s
2631 = 3.31s
2822 = 3.55s
2965 = 3.73s
3100 = 3.90s
3259 = 4.10s
3418 = 4.30s
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