Taking the time to measure the size of tractor tires and rims before purchasing and installation is a critical step in deciding how the tractor works.

When you have the wrong size of tractor tires and rims, the efficiency of your farm machinery will be greatly reduced. In worst-case scenarios, they can even cause an accident.

Let me take you through the process of measuring tractor tires and rims:

## Step 1: Get to Know What Tractor Sizes Represent

It is important to know what the figure or number on your tractor tire represents. Almost every tire brand size is given in standard or metric sizes. Here is how to have tire size decoding done.

### Tires with Two Numbers – What does that mean?

Most times tractor tires come with some numbers written on them. There are those with two numbers which can be seen in this form 11.3-14 or 10-18.2, etc. So, with 13.3-14 on a tractor tire, this is what it represents. 13.3 represents the width of the tractor tire and 14 represents the exact measurement of the wheel. This means, for a set like 13.3-14, the tire is 13.3 inches wide and is 14 inches rim fit.

### Tires with Three Numbers – What Does That Represent?

Seeing a number such as 30×13.50-14 is also common with tractor tires with three numbers. Here, 30 represents the outside height of the tire in diameter, 13.50 represents the exact width of the tire, and 14 represents the rim measurement that the tire fits.

Altogether, the 30×13.50-14 tire is 30 inches tall, 13.50 inches wide, and can mount smoothly on a 14-inch diameter rim.

With the above understood in this step, the rest of the steps become easier to follow.

## Step 2: Rim Measurement

Always starting rim measurements by getting the width of the rim first helps. When that is completed, the diameter can be measured.

### An accurate way to Measure the Width of a Tractor Rim

Start from the inside of the rim’s bead lip then move to the inside of its opposite bead lip.

### Accurate Rim Diameter Measurement

Start from the inner part of the rim’s bead lip then move to the bead lip’s first flange which is on the rim.

Most times, some of these tractor tires have their sizes stamped on them. These stamps can be seen on their bead flange. This saves buyers from going through measurements on their own. So, checking inside bead flanges is not a bad idea as well.

## Step 3: Measuring the Bolt Pattern of the Wheel

- Before you do anything, the number of bolt holes or bolt holes that need to be in the rim should be known. So, counting is necessary.
- When counting is completed, ensure it is the same as the axle hub.
- Now, the distance between holes can be measured. Begin from the center or middle of one bolt hole to that of another bolt hole. So, from one center to the other center.
- After the distances are measured, the bolt hole can also be measured.

Mostly, these rims come in two types of patterns. There are the even patterns and the odd patterns. Below are details on how to measure the two patterns;

### Measuring Bolt Hole Patterns with even numbers

- Begin with measurements of bolt holes from one bolt hole to the other. You should do this in a straight line.
- After that, measure two holes (from center to center of holes).

### Measuring Bolt Hole Patterns with Odd Numbers

With odd number patterns, it is not always certain that there will be a next hole. However, measuring is done as if there is.

- Start by measuring from center to center. So, it starts from the middle of hole A to the middle of hole B.
- Write down the distance recorded.

## Step 4: Wheel Bolt Hole Size Measurement

You can use a tape measure, ruler, or caliper for this process.

- Begin by taking your ideal measuring instrument.
- Take turns in measuring bolt hole diameter (that is measure each hole individually).
- Record the measurements you obtain in the process.

## Step 5: Wheel Offset Measurement

- Take time to measure the wheel from up to down.
- When the above is completed, the number obtained needs to be divided by 2. The figure got becomes the wheel’s vertical centerline.
- Move on to measuring the hub flange after the vertical centerline is got.
- Then, it is time to know the offset by taking the smaller figure and taking it out (subtracting) from the bigger number.

Note the following with offset measurements;

- When a positive offset it obtained, it means the mounting surface is outside.
- When the mounting surface is in the center or middle, it represents a zero offset.
- When the mounting surface is closer to the inside edge, a negative offset is obtained.

As you can see, measuring tractor tires and rims is quite a simple process. All you need is your measuring equipment. Besides, you should know how to interpret information on the tire.

**More Resources**:

How to Measure a Tire – Source: KARMAN

Tire – Source: WIKIPEDIA

Understanding Tractor Tire Dimensions – Source: RIM GUARD