Gear ratios are often a mystery to most drivers, but understanding them can help you feel more confident in your car. The gear ratio is the number of rotations that the drive wheel makes for every rotation of the axle. There are many advantages to knowing the rear-end gear ratio of a car. Some, such as engine performance and fuel economy, may require specific knowledge of what type of rear axle is in use. Different ratios will yield different performance and efficiency.
To determine what type of rear axle is currently in use on a vehicle, you can look at the vehicle identification number (VIN) that it has located in the upper right-hand corner on the dashboard.
Vehicle identification numbers vary in length and detail. A 15-digit Vehicle Identification Number (VIN) provides a wealth of information about a car’s safety and legal compliance, production and distribution, and history. The VIN can be decoded to identify the year, make, model, and specifications of your vehicle but can also be used to determine important details such as rear-end gear ratio.
If you’re comparing cars and want to know which one offers the best acceleration, you should look at the first number in the gear ratio. For example, if your car has a 3.54 gear ratio, then it turns three times for every rotation of the driveshaft. This means that when you take off from a stoplight, your car will accelerate faster than a vehicle with a lower gear ratio.
A low number, like 2.73 or 2.93, indicates that your car’s engine rotates faster than most other cars when driving at highway speeds. A high number, like 5.14 or 5.38, means that your engine rotates more slowly than most other engines at highway speeds.
VIN code may contain the gear ratio
Every automobile has a 17-digit identifier that allows it to be identified and tracked. A VIN contains information about the vehicle, such as the brand, model, year, and engine size, in every number and letter.
Some, but not all, of these VINs will include a code for the vehicle’s gear ratio. However, this will mostly depend on the information included in the VIN’s vehicle descriptor section (VDS).
Here are three simple techniques to assist you to figure out what your VIN code is:
Step 1
It’s simple to locate your vehicle’s VIN. It’s imprinted on a metal plate placed in the dashboard just above the steering wheel and on a sticker inside the driver’s side door. It’s also on the title of your automobile.
Step 2
The VDS section of the VIN is the fourth to eighth digits. The model, displacement, and body type of the vehicle are often included in this section. Gearbox ratios may not be contained in every vehicle manufacturer’s VDS, but if they are, this is where they may be located.
Step 3
The National Highway Traffic Safety Administration provides VIN decoder information. Different manufacturers will use different digits and put them in a separate order.
Make sure to look in the glove box if your VIN does not include gear ratios. Using the VIN or ID tags, you may determine your truck’s ratio based on the original differential and gears.
Gear Ratio: Count the Wheel Turns
If you want to double-check that your tags are correct, use the methods below to determine how many times the wheel rotates every drive shaft rotation.
- Count the times your driveshaft revolves per one complete wheel revolution as you rotate the back wheel towards the car’s front. And the result is your ratio.
- Keep your front tires from moving by putting a block in front of them.
- Lift the truck’s back end so that the back tires are above ground level.
- Place the vehicle in neutral while it is lifted off the ground.
- The driveshaft should be marked with a visible indication from a safe distance.
- Count the number of times the driveshaft rotates each wheel rotation as you turn the back wheel toward the front of the car. This will give you the ratio.
Gear Ratio: Divide the Ring and Pinion Teeth
If you are still unsure of your gear ratio, you can use this method. Count the teeth number on the ring and pinion gears by opening the differential cover. Now divide the ring gear’s teeth by the pinion’s teeth. The result is the ratio.
Table of Contents
Where is the gear ratio stamped?
If you can’t find your gear ratio stamped in your vehicle then you can still identify what gear you have in your rear end. The easiest way to do this is by counting the teeth on your ring gear and pinion gear.
This is an accurate way to identify what gear ratio that you have and is much more reliable than using multiple gears from other vehicles to try and match up with yours because each ring and pinion gear could be different from one another.
A great example of this is when you take two gears from two different gearsets equipped with different ratios and expect them to match up perfectly because they are close to each other but not exactly the same.
Rear-wheel drive vehicles have a differential in the rear axle assembly. The differential allows the vehicle to turn corners by allowing each wheel on the axle to rotate at different speeds.
The rear end ratio tells you how many turns of the wheel are needed for one turn of the driveshaft. The driveshaft connects the differential to the transmission, and it turns at the same speed as the engine. A higher number means a faster-spinning driveshaft or larger diameter wheels with less tire rotation needed for a given distance.
For example, if you have a 10.00:1 ratio, it will take 10 wheel rotations for one turn of driveshaft. This means you need large, low-profile tires because they will go farther before needing to be turned again. If you have 3.50:1, it will take 3 1/2 wheel rotations for one turn of driveshaft. This means you need smaller, high-profile tires because they have to turn more often and they don’t travel as far while making one revolution.
Why Is It Important To Know Your Gear Ratio?
Gear ratios are the attributes that determine how fast a car can go. It’s similar to how gears on bicycles work. The higher the gear ratio, the greater the mechanical advantage and the faster you can ride. The lower the gear ratio, the lower the mechanical advantage and slower your bike will go.
The same is true of cars. The gear ratio is determined by multiplying its number with that of its corresponding axle. For example, if a car has a 4-speed transmission, it means that it has 4 forward gears and 1 reverse gear. This essentially means that there are 4 wheels on the ground moving at one time and one wheel being held in reverse for brakes.
It’s also important to note that there are different types of transmissions and each one has their own set of ratios assigned to them. These are called internal gearing or gearing ratio. Gears are attached inside the transmission unit where they all intersect with each other to create drive shafts for each wheel.
Each type of internal gearing is more suited for different types of driving styles and terrains – whether it be off-roading or racing through traffic in downtown city streets.
Check: Off road vehicles
Chevy rear end gear ratio chart
Learn more about our Chevy Rear End Compatibility chart to ensure that you are making the right choice.
Chevy 10 bolt rear end gear ratio chart
What do gear ratios tell us?
gear ratio: The number of rotations of the crank arms per revolution of the rear wheel. The more gears you have, the smaller the difference in ratios will be between them (eg: on a 27 speed bike there would be 9 steps between one gear and another, while on a 3 speed bike there are only 3 steps between each gear).
The reason why you need to know your gear ratio is that it allows you to work out exactly how fast you will travel per pedal revolution, which in turn allows you to plan your training sessions effectively. If you are going out on a ride with a particular duration and distance in mind then knowing your average speed per crank rotation will allow you to calculate how long it will take you to reach your destination and back again.
Gear ratios tell us how many turns of the wheels are required for one turn of the driveshaft. The higher the number, the faster the vehicle will be able to go up a hill.
Notes:
1- Calculate gear ratio by dividing the number of teeth on the pinion gear by the number of teeth on the ring gear.
2- Gear ratio does not include a differential factor. This is because a differential is not part of an internal gearset. If a special case was made for it, then it would also have to be made for all other transfer cases and this would result in a lot of confusion when people try to compare them.
Multiply your engine’s power by your transmission’s gear ratio to get your vehicle’s power at the wheels.
Truck gear ratios are usually classified in two ways:
1) High range/low range: This system is commonly used to describe 4×4 trucks. The high range ratio is used for highway speeds and the low range ratio is used for off-road speeds.
For example, a 4×4 truck with a 3.55 rear axle ratio has a high range ratio of 3.55:1 and a low range ratio of 1:1. Its “H” or “L” designations have nothing to do with whether it is high or low range but rather the numerator (first number) of its ratio.
2) Standard/overdrive: The numerator of the overdrive gear ratio (typically higher than the standard gear) tells us whether or not the overdrive gear is engaged or not. This will usually be represented by OD (Overdrive) after the numerator if it is engaged, and just the numerator if it is not engaged.
FAQ
How to Find the Gear Ratio from Vin Chevy?
The Chevy VIN starts with a “C,” following country code in the 2nd digit. The third digit is the built year, while the fourth digits represent assembly plants. The next digit is a letter or a number. And The final digit is the serial number.
Need a new Chevy differential rebuilt kit?
How to Find rear end gear ratio by VIN Dodge RAM?
Some of the Dodge RAM doesn’t come with a VIN identifier in the truck. In that case, you have to look for the ratio sticker that is located at the bottom of the axle tube.
How to Find rear end gear ratio by VIN ford?
You can find the gear ratio on your ford from the SCC Label on the driver’s side door panel.
How to Find rear end gear ratio by VIN jeep?
Remove the diff cover and divide the ring gear’s teeth by the pinion gear’s teeth to get the end gear ratio of your Jeep.
How to find rear end gear ratio by VIN?
You can find the gear ratio in the VDS section of the VIN.
How to Find Rear End Gear Ratio by VIN GMC?
Find the VIN: Typically locate the VIN on the driver’s side dashboard, the door jamb of the driver’s side door, or on the vehicle registration or insurance paperwork.
Decode the VIN: Gear ratio information includes in the 8th to 10th characters of the VIN. The characters show different information about the vehicle, including engine type, body style, and options.
Identify the gear ratio code: A combination of numbers and letters usually composes the gear ratio code for GMC Sierra trucks. Use a VIN decoder tool to identify the gear ratio code based on the VIN.
How to identify rear end gear ratio?
There are 3 different ways to identify the rear-end gear ratio: Vin code, Dividing the Ring and Pinion Teeth Count, and counting the Wheel Turns.
Conclusion
Knowing your car’s rear end gear ratio can give you a greater understanding of your car and help in changing different parts. After going through the article, now you know where to look on. If you still have any questions, don’t hesitate to shoot below.
