When buying tires for your car, you need to know the wheel diameter. You can find it out from the technical documentation, when contacting the seller or car service, or on your own.
Necessary
- - car tire;
- - a centimeter tape or tape measure to measure the distance;
- - a marker to make a mark on the tire;
- - stick to put marks on the ground at points "A" and "B";
- - calculator to multiply the resulting distance by the number "pi".
Instructions
Step 1
So, find in the documents that must be available in every car, the section "Wheels". Try to find there lines that speak about the diameter of the wheels of your automobile vehicle. Diameter can be specified in either centimeters or inches. Most often, the diameter of the front and rear wheels of a car is the same. The only exception is sophisticated agricultural machinery.
Step 2
Examine the old tires carefully. They could have retained special markings indicating the characteristics of the wheels.
Step 3
In the event that it was not possible to find the marking, use a method that can be used without complex measuring instruments. To do this, draw two lines: one on the ground, the other on the side of the tire that faces you. You can just put a point on the tire.
Step 4
With the tire on the ground, mark where the dot touches the ground. Let's call this place "point A". Then roll the tire on the ground until it makes a full circle. The point on the tire should again be on the ground at some distance from the starting point. Mark this place by designating it "point B".
Step 5
Measure the distance between points A and B. Divide the resulting distance by pi, which is 3.1415. This will give you the diameter of your wheel.
Step 6
It is best to do all calculations in inches. If you are unable to do this, convert the size from centimeters to inches yourself. One inch equals approximately 2.54 centimeters. So, if you got 40.64 centimeters, divide that by 2.54 for 16 inches.
Step 7
You can also go to a car service, where an experienced technician will determine the diameter of the wheels using specialized tools. In this case, all calculations will be immediately performed in inches, which will facilitate your task.
