A inflation pressure maintenance regime which regularly checks and records inflation pressure data is critical to the successful operation of OTR tyres. To ignore such a regime is to burden your operation with extra costs.

Simply put Air is to Tyres as Oil is to an Engine.

Without the appropriate quantity of oil an engine will over heat, it will sustain unseen damage, the engines life will be shortened by a considerable amount if it doesn't fail prematurely. A tyre is no different yet we religiously check oil levels far more frequently than we check tyre inflation levels. Why??

In a haul truck engines life (15,000 hrs) between 3- 5 sets of tyres will be consumed; (this assumes wear out, ie it discounts any damage sustained to the tyres). The cost of say 24 tyres (4 sets x 6 tyres) far outweighs the cost of rebuilding an engine, (e.g. 24 x 40.00x57 = $840,000 @ $35k/tyre).

How is your maintenance program geared towards protecting your investment in machinery? Are your tyres given the same treatment as your engines? Engines receive daily oil level checks, fresh air filters, regular oil filters, SOS oil sampling, what do your tyres receive, weekly checks at best?

Consider protecting your investment by checking and recording inflation pressures on ideally a daily basis, minimum three times weekly.

A tyre relies upon the air contained within the tyre to support the load placed upon that tyre. If the air volume is reduced then the load must be reduced accordingly. A tyre under inflated by 20% will support only 75% of its nominal load capacity before it is considered to be overloaded. Overload equals overheat, such heat is the arch enemy of a tyre, it means certain degradation of capacity and performance.

Bodies such as Australian Tyre & Rim Association, ETRTO (European), JATMA (Japanese) & IT & RA (American) all specify pressure load speed capabilities as standards for tyre users to reference. Many OTR tyre users ignore these values and load their tyres heavily, then wonder why their tyre operating costs are high. They blame the tyre simply because they don't understand tyres & their capabilities.

When tyre inflation pressures are checked the actual figure as well as the adjustment or reset figure should be recorded. Tyre assemblies that have a history of reducing pressures should be disassembled and inspected to determine the reason for the pressure loss. OTR tyres and rim bases can fail catastrophically with large destructive forces, early intervention may save such an event from occurring. Tyre manufacturers will call for pressure records as evidence that the tyres have been maintained as per specifications in the advent of a warranty claim. The investment in recording the data will be repaid on the first warranty claim that is made.

One area that is never considered by production management is the aspect of fuel consumption. A tyre that is overloaded (either by design or by poor management) has a considerably higher rolling resistance than a properly inflated / loaded tyre. Fuel consumption in the order of +10% is not unrealistic when considering rolling resistance, the higher the overload the higher the rolling resistance, the higher the fuel consumption.

Various devices are available to assist in verifying tyre inflation pressures. There is a deal of conjecture about the validity of the different methods but absolutely nothing beats a knowledgeable and dedicated tyre service man. Viewing each tyre on a daily basis he gets to know each tyre on a first name basis, what damage has been sustained, which tyre has a pressure retention problem, what tyres are due for rotation to maximize wear potential.

Tyres are generally the second or third highest cost centre on an operating mine, are your tyres given the attention that is due to them?

Show an OTR tyre, one shot at correct pressure, 1 @ 10% down, 1 @ 20% down, 1 @ 30% down. Pick the difference number your choices then compare to reality.

Here's the real situation ...

Are you comfortable with just looking at your tyres to determine the inflation pressure now?

If the answer is "no" then perhaps COBA Engineering can assist you to reduce your tyre operation costs and provide the added bonus of increased production!