Load and Speed

Load

The load carried by each tyre should be within the TREDCO recommendations for the particular tyre size-ply rating and inflation pressure. The operator responsible for loading the vehicle must spread the load evenly across the pan to ensure a uniform load distribution on the tyres. In all cases, the prescribed load should not be exceeded. When determining the load to be carried the following must be borne in mind:

1. The load on each vehicle must be kept within the limits specified for the vehicle. Overloading must be avoided.
2. To determine the maximum permissible load, refer to the load inflation table for the particular tyre size, ply rating, cold inflation pressure and speed.

Damage due to over-loading

Overloading a tyre results in the tyre experiencing the combined effects of over- and under-inflation. The tyre will be susceptible to excessive tread and sidewall movement, cord tension and bead stress resulting in excessive heat generation. Tyre life will be adversely affected and early life failures, such as separations, impact fractures, penetrations and reinforce flex breaks, can be expected.

1.Overloading reduces the life of a tyre.
2.Overloading will cause permanent tyre damage.

Tyre damage due to over-loading

• Seperation due to excessive heat.
• Cord and beaddamage due to excessive deflection.
• Uneven wear due to excessive tread movement.
• Cut and impact damage due to increased cord tension.

Speed

The operator of the vehicle must adhere to the speed limits laid down by the management. Th maximum speed permitted should not exceed the maximum speed classification of the tyres stipulated by Bridgestone Firestone. In the interests of safety the operator of the vehicle should always take the prevailing conditions such as climate, haul road conditions, gradient and visibility into account.

Damage due to excessive speed

Excessive speed results in higher heat generation due to the increase in the rate of flexing that takes place. This can result in tyres failing due to heat separations, impact fractures and penetrations. The life of the tyre will be adversely affected due to increased rate of wear caused by excessive braking and sliding while cornering.

Correct working speed

1. The correct speed is determined from both the vehicle's maximum speed and the conditions prevailing on site.
2. The following is a list of recommended maximum speeds under ideal conditions.
3. For special conditions, not covered in this site, contact your Bridgestone Firestone representative for recommendations.

Tyres used on Loader/Dozer and Underground scoops are fitted with special abrasive- and cut resistant tread compounds. These tread compounds are suited for slow moving vehicles in rough underfoot conditions and not for haulage type operations Machines in load-and-carry operations should not exceed these limits.