Wheel swaps are carried out for a number of reasons including:
- Tread Depth Alignment
On twin positions such as on the drive axle of a tractor unit, wheels are swapped in order to pair tyres with similar or matching tread depths. A misalignment of tread depth results in the vehicle load being carried unevenly across the tyres which in turn can lead to the premature wear of tyres.
- Tread Depth Alignment Across Axle
On a trailer it is recommended that the tyres with the largest amount of tread are placed on the rear axle, whilst tyres which have been recut or have low tread are placed on the middle axle. This configuration ensures maximum tyre life across all positions, and as such fleet checks are used to highlight where swaps can and should be made.
As recuts should not generally be placed on a steering axle, it is common that a non regrooved tyre from a lift axle will be swapped with a steer axle tyre which has just been recut in order to prolong tyre life whilst also ensuring optimum safety on the road.
On many occasions wheel swaps are also combined with a turn on rim where sloped or irregular wear has been highlighed as a problem.