Mustang Gear Ratio to RPM Comparison Chart

Mustang Gear Ratio-to-RPM Chart For Mustang Transmissions

Estimated RPM Range for Highway Driving (~65MPH)

Anyone who’s purchased a used Mustang before knows how annoying it can be to figure out if the previous owner changed the rear gear ratio or not. Sometimes, you know they were changed but have trouble identifying what ratio the new gears are. Below, we have mapped out the usual suspects when it comes to aftermarket gear ratios. If you do not see the RPM for which you are reading at 65MPH for your particular transmission you can safely assume by going with whatever ratio of gears falls between the provided sets.

This chart will also give people who are thinking about changing their Mustang’s rear gears a look at the increase in RPMs they will see for each ratio. Note that the smaller the gear (smaller gears have higher ratios – 4.10s are SMALLER than 3.73, ect.) the more RPMs. Higher ratio gears can actually increase fuel efficiency around town but will use more fuel when driving on the highway, and vice versa.

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