WCF: Work Capability Factor
Just like the TKPH, a tyre’s WCF is also determined by the star rating and, in particular, the used rubber compound. Once again, tyre will be heat resistant, cut resistant or a combination of the two.
The following formula applies for the WCF (average load x average speed):
WCF = ( (Q loaded + Q empty) / 2) x (N x L) )
- Q loaded = Load per tyre on the loaded vehicle
- Q empty = Load per tyre on the empty vehicle
- N = Number of cycles per hour
- L = Length per cycle in kilometres (there and back)
In this case, also consider the environment temperature and the dispersion of total weight when loaded.
|Load per tyre||Empty||14,000 kg|
|Number of cyles per hour||35 cycles|
|Distance per cycle||250 metres (0.25 km)|
Average load: (28,000 + 14,000) / 2 = 21,000kg (21 tonnes)
Average speed: 0.25 km x 35 cycles = 8.75 km/h
WCF: 8.75 km/h x 21t = 184 WCF
The tyre’s WCF value must exceed the actual (calculated) WCF value during use, otherwise the tyre will be unsuitable. Therefore, in the example above, one must select a tyre with a WCF value of 184 or more.