T. K. P. H.
How to use Ton-Kilometre per
The Ton Kilometre per Hour
factor 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
The TKPH rating data are
applicable in the following situations:
To all standard, heat or
Ambient temperature less Than
Maximum trip distance less than
Maximum speed of 50 km/h.
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. The load carried by the individual tyre
must be in line with the recommendations as specified by TREDCO. Refer to
load/ inflation tables.
TKPH Conversion Factors
For temperatures in excess of
380 - The TKPH should be reduced by approximately 2% for each
degree C rise above 380.
For temperatures lower than 380
- The TKPH should be increase by approximately 1% for each degree C below 380.
Calculating TKPH (to determine
actual work rate of an operation)
1. Obtain average of empty and
loaded mass per tyre in tons for each axle. (If no scales available, use
specification sheet masses as best possible estimate).
Mean Tyre Load in Ton = ( Empty
Mass in kg + Loaded Mass in kg ) / ( 2 * 1000 )
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
5. Calculate overall average
speed based on Items 2, 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 calculated TKPH
requirement is higher than the TKPH rating of the tyre being used, reduce
speed and/or load or use a tyre with higher TKPH rating.
TMPH AND TKPH EXCHANGE: