How do you find the ratio of a diff?
Turn the wheel TWO revolutions and count the number of driveshaft turns. The number of driveshaft rotations will help you determine your rear axle ratio. For example, if it turned 3 and a half times, it’s a 3.50:1 ratio. If it turned 4 and a quarter times, it’s a 4.25:1 ratio.
How do you find out your diff gear ratio?
At 10 wheels spins the masking tape on both the tyre and the driveshaft should land in the same original postion as the starting point. Usually there is a sticker on the diff housing that says what the ratio is but if in doubt, this is the best way to know exactly what gears you have.
Why do you need to change diff ratios?
Think I’ve got it. So keeping the same 12″ tyre size, a 3.1 diff would in effect mean that the the wheel would turn once with less revolutions of the input (engine) so at the same revs would be turning more than a 3.6 diff? I take your point about changing diffs to suit tracks; that explains why the diff needs to be changed (or the wheels).
What does a 3.254 diff ratio mean?
For example a 3.254:1 first gear ratio means that for each 3.254 revolutions of the engine the gearbox output turns once, a 1:1 fourth gear means that the output turns once for each each engine revolution. This gearbox output is then stepped down again by the diff.
Which is better a higher diff or lower diff?
So a 3.9 diff takes 3.9 turns of the gearbox output to get one revolution of the wheel. Therefore a higher ratio diff would give a lower top speed but a more rapid acceleration, and conversely a lower ratio diff will give a higher top speed (or more relaxed cruising since lower engine revs are required for a given speed) but slower acceleration.
How can I find out what my differential ratio is?
Take a drive and record the rpm at 105 km/h (65 mph), the next step is to work out what the current ratios are in the vehicle. This can be revealed by calling the manufacturer or even calling a differential repairer giving him/her the Vehicle Identification Number, also known as VIN.
What should the diff ratio be on a car?
But looking at 4.10 with the rpm at 2713 is the closest to 2809 stock rpm. Even with the help from the differential gear ratio chart and the right diff ratio installed, the vehicle will never regain its fuel economy it had before simply due to the fact that larger tires will have a bigger rolling resistance.
How can I find out my gear ratio?
So an easy way to determine your actual gear ratio is to check the tag attached to the differential cover by the cover bolts. On the tag there should be some numbering such as 3.54 or 3.73, either of those numbers will give you the stock axle ratio.
How to compare two files with Diff tool?
Diffchecker is a diff tool to compare text differences between two text files. Enter the contents of two files and click Find Difference