RE-GEARING YOUR REAR-END: HOW TO CHOOSE THE RIGHT GEAR RATIO?

by Brittany Foster

Re-gearing is one of the most crucial decisions when it comes to your car’s performance and it may seem like a daunting task if you’ve never done it before. Re-gearing is all about finding the right ratio that will suit your driving needs and your car’s engine performance. Whether you need to be the quickest off the starting line, or drive for long distances on the freeway, gearing can make or break your car’s performance.

For starters, you should know that the numerical value of your gear ratio is how many times the driveshaft spins to rotate the rear wheel one time. To figure out a ring and pinion gear’s ratio just by looking at it, you take the number of teeth on the ring gear (driven gear) divided by the number of teeth on the pinion (drive gear). So whether you’re driving 25 mph using a 3.25 ratio gear or 60 mph, the drive shaft will always spin 3.25 times to turn the wheel in one rotation.

Now to the difference between tall gears and short gears- what does this mean? The difference between tall and short gears is really just referring to the ratio. Tall gears have LOWER ratios (2.80, 3.00, 3.25, 3.40, etc.), whereas short gears have HIGHER ratios (4.71, 5.00, 5.14, 6.50, etc.). Kind of confusing, right? A great way to remember the difference is TALL gears give you TOP speed because the gears are longer. On the other hand, short gears give you more acceleration off the line but less top speed which isn’t ideal for highway driving, but is great for racing applications.

Low and high ratios v1

When you’re choosing the right ratio for your differential, there are a few things to take into consideration other than your driving habits which include your transmission ratio, tire diameter, final drive ratio, and engine RPM. No matter the engine size, if you choose a gear that isn’t short enough (or a higher ratio) your car won’t be able to accelerate quickly. For example, if you ran a car with a 400 HP engine and a 6.20 gear in the rear-end, against an 800 HP car with a 3.25 gear, the 400 HP car would accelerate much quicker off the line than the 800 HP car. For your convenience, we have a gear ratio chart that gives you an idea on what gear ratio to choose. This is just a general calculation so if you choose a gear that’s a little higher or lower, it won’t drastically affect your car’s performance.

When you install a new gear set, it’s also important to follow gear break-in procedures so that your gear set doesn’t prematurely fail. If you’re installing one of our Lightning Series gears, break-in is not necessary due to the superfinishing treatment that the gear sets undergo and are available for our entire product line. When you’re ready for your next gear swap, make sure to choose the right gear ratio that will improve your car’s performance and get you where you need to go.

To find a distributor near you, please click here, or if you have any questions, please contact us at sales@usgear.com. Download our 2019 US Gear catalog here.

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COMMENTS:

  • Andre laurin:

    Jul 25 2019

    We have worked with your product in most intence environment , and cant say enough on how much your product over delivers on its value .

    Simply Amazing

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