them when moving to the back. If the tires are unidirectional, the rotation can only be rotated front to back on the same side of the vehicle to preserve the rotational direction of the tires, unless they are remounted. More complex rotation patterns are required if the vehicle has a full-size spare tire that is part of the rotation, or if there are snow tires. Alternative views The benefits of achieving even tire wear, using rotation, are disputed. Some car manufacturers recommend against performing tire rotation, for example BMW. Many tire manufacturers say that tire rotation is no longer necessary, except to ensure that best tires are fitted at the rear of the vehicle. In practice this means that when the front tires become worn, the new ones should be fitted to the rear, moving the old rear tires to the front. Best tires on rear of vehicle Maximum vehicle control is achieved with the best tires on the rear wheels of the vehicle, whether it is front- or rear-wheel drive. The reason for this is that if the rear wheels lose grip before the front ones, an oversteer condition will occur, which is harder to control than the corresponding understeer which will happen if a front wheel is lost. So the intuitive belief that the front steering/driving tires need to be the best quality is not the case. This is also the case if a tire blows out. A rear tire blowout will cause the vehicle to become very difficult to control, especially at highway speeds. It also greatly increases the risk of rollover due to yawing, a condition where the rear of the vehicle swings out and becomes perpendicular to the direction of travel: yawing can cause the tire to separate from the rim, leading the rim to dig into the pavement, or dirt and grass if no longer on the road, which can trip the vehicle and cause its rollover. References Motor vehicle maintenance Automobile wheels Tires