How can I check the gear ratio that is on the rear axle?
You can work it out using this tool:
www.performanceprobe.com My handbook said 3.73 but I actually had a 3.91 final installed.
e.g. Mazda ratios from:
1st 3.136
2nd 1.888
3rd 1.330
4th 1.00
5th 0.814
Put in your tyre sizes and change the ratios for the diff. Then compare with the MPH/KPH to RPM in your car.
