COMMERCIAL VEHICLE TYRE DATA - wheels, rims and valves

Maintaining wheels and fixings in good order

Wheels and wheel fixings should be maintained in first class condition at all times and tightened in the correct sequence to the correct torque settings. All refitted wheels should be rechecked for tightness after the vehicle has covered 50km using a calibrated torque wrench.

Causes of wheel loss in commercial vehicles

Wheel loss can have catastrophic results and upon investigation the majority of cases would fall into the following categories:

• Over tightening:
  this causes excess stress in the studs, nuts and other components - often causing complete and sudden failure
• Under tightening:
  runs the risk of nuts working loose and subsequent wheel loss
• Foreign Matter:
  dirt, dust, rust or paint being trapped between components when tightened, later collapsing, resulting in the fixing working loose
• Reused, worn or damaged components:
  damaged wheel nuts, studs, etc can be appear to be set to the correct torque settings but may not clamp the wheel properly and lead to wheel loss

Types of Tyre Valve

There are almost as many types of tyre valve as there are types of truck tyre. For instance, there are rim valves for tubeless tyres, rim valves for super-single tyres, single bend valves, double bend valves, triple vend valves, universal spud valves and valve extensions.

The valve's main purpose is to keep the air in the tyre. Always replace the dust cap after checking pressures - preferably the metal type that acts as a secondary air seal keeping dirt out. Valves should always be replaced when a new tyre is fitted.

Wheel Balancing saves money and downtime

Unbalanced tyres and wheels waste money by causing uneven, excessive tyre wear and needless wheel bearing damage. Unbalanced wheels can also aggravate problems created by incorrectly tightened wheel bolts. They also have a bad effect on braking and steering performance and cause vibration through the steering and suspension.

When a new wheel-tyre assembly is fitted it should be balanced.

Bedding in new tyres

All new tyres should be 'bedded in' at lower speeds for the first 300km or so to allow the tyre beads to seat firmly onto the wheel rims.