TKPH stands for Tonne Kilometers per Hour and is an essential expression of the working capacity of a tire. It represents the load capacity of a tire in relation to heat generation. A tire’s TKPH depends on its design and varies according to size, type and compound.
The Ton Kilometer per Hour faction is of great assistance in determining the suitability of a tyre for an operation. The following factors must be borne in mind with regards the TKPH factor when selecting a tyre Maximum operating TKPH should not exceed the tyre TKPH rating. The average operating TKPH to be calculated after several checks, and should not exceed the tyre TKPH rating.
The TKPH rating date are applicable in following situations:
To all standard, heat or cut-resistance tyres
Ambient temperature less than 38℃
Maximum trip distance less than 5 km
Maximum speed of 50 km/hour
TKPH Adjustments
The TKPH factor is influenced by heat. When the heat in the tyre increases due to abnormal conditions such as high ambient temperature, speed and overloading the TKPH should be reduced. Similarly adjustments to the TKPH can be made if the ambient temperature or the speeds are low.
TKPH Conversion Factors
For temperatures in excess of 38℃ – The TKPH should be reduced by approximately 2% for each degree rise above 38℃
For temperatures lower than 38℃ – The TKPH should be increase by approximately 1% for each degree below 38℃
Calculating TKPH (to determine actual work rate of an operation)
1.Obtain average of empty and loaded mass per tyre tons for each axle. (If no scale available, use specification sheet masses as best possible estimate). Mean Tyre Load in Ton = (Empty mass in kg + Loaded Mass in kg) / (2*100)
2.Obtain overall length of round trip per haul from an engineer.
3.Obtain number of loads hauled per shift from contractor’s load count.
4.Obtain total shift hours from contractor.
5.Calculate overall average speed based on Iteams2, 3 and 4. Work Day Average Speed = (Overall round trip length * Number Loads per Shift) / Shift Hours.
6.Calculate TKPH based on the HEAVIEST loaded tyre in Item I and average speed from Item 5. TKPH = Mean Tyre Load * Work Day Average Speed.
7.If the calculate TKPH requirements is higher than the TKPH rating of the tyre being used, reduce speed and/or load or use a tyre with higher TKPH rating.
