Technical Dictionary

Off-the-car balancing

To achieve the optimal weight balance between the tyre and the wheel, the assembly can be taken off the vehicle and balanced to eliminate both side-to-side shimmy and hopping up and down.

Offset

The offset of the rim is what locates the tyre/wheel assembly in relation to the suspension. A wheel with zero offset has a mounting face that directly aligns to the wheel’s centerline.

Overall diameter

The diameter of the inflated tyre, without any load.

Overall width

The distance between the outside of the two sidewalls, including lettering and designs.

Oversteer

The tendency for a vehicle, when negotiating a corner, to turn more sharply than the driver intends. The rear end of the vehicle wants to swing toward the outside of a turn. A handling condition in which the slip angles of the rear tyres are greater than the slip angles of the front tyres. An oversteering car is sometimes said to be “loose,” because its tail tends to swing wide.

Oxidation

Rust process that takes place in the steel belts when moisture, via damage, is allowed to get inside the tyre. This can result in the tyre becoming unserviceable before normal replacement time.

Original Equipment

Tyres selected by a vehicle manufacturer that best match tyre performance to vehicle performance characteristics. Also known as OE.

Over-inflation

Too much air in the tyre, resulting in premature wear in the center of the tread.