How hard must OTR tyres be?
Too high or too low – both have negative consequences
Here are a few examples (compared to ideal - recommended - pressure): if air pressure is 50% too low, this reduces life span by 80%; if air pressure is 50% too high, this reduces life span by 30%. This decrease is 20% if pressure is ‘just’ 15% too low and 10% if pressure is 15% too high.
However, life span is not the only factor to be negatively influenced by e.g. (very) low pressure. For instance, there is more premature damage and a decrease in safety because various parts of the side wall tend to overheat.
Determining suitable air pressure
What do you need to look for when deciding how much air to put in your OTR tyres? Several guidelines need to be taken into consideration:
- Determine the total weight of the vehicle by checking the manufacturer's details or by weighing each axle separately.
- Calculate the load per tyre (for - mobile - cranes, divide the total weight of the vehicle by the number of axles and then divide this figure by 2). Make sure you take into account any extra loads placed on each axle (like the counterweights on cranes).
- Use the ‘bearing capacity per tyre and air pressure’ overview to select the appropriate table for the concerned vehicle.
- Also take into account information relating to haulage and transport.
- It is sometimes possible to use lower tyre pressure when special vehicles are used at low speeds.
In some cases, it is best to take extra - precautionary - measures to reduce the likelihood of a flat tyre. This can be done by replacing air in the tyre with polyurethane. This will then stop tyres from puncturing when they are damaged.