# Help

## TYRE SIZE AND WHEEL FITMENT GUIDE

Tyre Specifications

Tyre Sizing

Speed Ratings

Tyre Size Calculator

Wheel Fitments

Offset

Bolt Patterns

Centrebore

Wheel Fitment Calculator

#### TYRE SIZING

Passenger Tyre sizing is typically displayed as:

P 215 / 65 R 15 89H

#### SPEED RATINGS

The speed rating of any tyre is a measurement of the top safe speed the tyre can carry a load under specified conditions. See the chart below for conversion:

The load rating for any tyre (load index) indicates the maximum weight that each tyre is able to support. Below is a quick rating of common Load Indexes:

#### OFFSET

The offset of a wheel is the distance from the mounting surface of the wheel to the true centerline of the rim. A positive offset means the mounting surface of the wheel is positioned in front of the true centerline of the rim / tyre assembly. This in effect brings the tyre in to the guard well more. Conversely, a negative offset means the mounting surface of the wheel is behind the true centerline of the rim / tyre assembly. This will cause the tyre to stick out away from the vehicle.

#### BOLT PATTERNS

Each wheel has a different bolt pattern, and some wheels even have 2 different bolt patterns which allow it to be mounted on a wider range of vehicles.

Most Bolt Patterns are represented in the following manner:

4/100

The "4" indicates the number of holes in the wheel for the bolts to enter and mount the wheel onto the car.

The "100" indicates the diameter of the bolt circle measured in millimeters or inches. 4 & 6 bolt wheels are measured from the center of one bolt hole to the center of the bolt hole directly across from it. On a 5 bolt pattern, it is a bit trickier to measure without special tools. Imagine a circle running through the centers of each bolt hole. You would measure from the center of one bolt hole to the imaginary circle that lays between the opposite two bolt holes.

#### CENTREBORE

This relates to the center hole in the wheel that centers the wheel on the hub of the car. Since most wheels are mass produced, they have a large center bore to accommodate several different vehicles. If this is the case, it is recommended that you use a hub ring. Hub rings are hard plastic or metal ring that fits between the wheel and the vehicle. This centers the wheel perfectly on the hub ensuring that there is no run out when the wheel is installed on to the vehicle. Without hub rings it is possible to get vibrations even if the wheel / tyre assembly is perfectly balanced.