How to Choose Fox Body Rear Gears

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Nothing will wake an old Fox Body Mustang up like a set of new gears. You'll get off the line faster and into the heart of your power band quicker than the competition, resulting in lower track times and a more enjoyable driving experience.
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When it comes to upgrading the performance of a Mustang, the first mods that everyone generally thinks of are intake, tune and exhaust. There is another mod that definitely deserves to be included on the list of Must Have Mods - that being Gears! Gears will transform your Mustang from a tame pony into something more deserving of its nameplate. The increase in performance combined with the low cost means this is one of the best bang for your buck mods that you can do to your Mustang.
Ford Mustang Ring & Pinion Gears

What exactly are Mustang gears?

Gears can be a pretty general term but in this case, they refer to the ring and pinion gears that reside in the rear differential. Without getting too much into the technical details of how they work, they essentially convert the power coming from your driveshaft to power needed to turn your wheels.

Gears are referred to by ratios, such as “3.31 gears.” This means that the driveshaft needs to turn 3.31 times in order to turn your wheels once. People upgrade to numerically higher gears because increasing this number gives your engine more leverage and makes it easier to accelerate faster. Higher gears, such as 4.10 gears, can be referred to as a steeper gear. A set of 4.10 gears will also result in a decrease of your top speed, which is why they can also be referred to as shorter gears.

What gears should I get for my Fox Body Mustang?

Mustangs came from the factory with anything between 2.73 to 3.31 gears. By far, the most popular upgrades are 4.10 and 3.73 gears. The gear set you choose depends on your end goal and how you drive your Mustang.

Benefits of 4.10 Gears in a Fox Body

  • Rapid Acceleration – Hard Launches

  • Great for drag racing

  • Mix of city and highway driving

Benefits of 3.73 Gears in a Fox Body

  • Superior Acceleration

  • Great for road racing/long commutes

  • Most driving is done on the highway

Results after installing your Mustang's new rear gears

Either set of gears will instantly transform your Mustang and make it feel like a completely different car. You’ll be able to chirp tires on command and you’ll be accelerating noticeably faster. Many people are curious if getting 4.10 gears will make a big impact on your fuel economy. The simple truth is that your driving habits make a much bigger impact on fuel economy than what gears you have. Many people who get 3.73 gears at first end up upgrading again to 4.10 gears, so don’t fear the gear and make your decision based on performance expectations.

We’ve had many customers ask what their RPMs will be at a given speed after installing gears. To show you exactly what effect gears will have on your car, we’ve created RPM tables that are on all gear product pages. You’ll be able to see exactly what RPM your engine will be turning at various speeds before buying gears.

Once you’ve decided on what gears to buy, head over to Gear Installation article to see what you need for smooth and trouble free install.

FItment includes:   •   1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, LX, GT, SVO, Cobra Mustangs

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