Load Ratings & Calculations

All Capus EEC approved Kingpin Assemblies have been tested in Germany by RWTuV. The tests include a simulated life test - 2 million cycles at the approved 'D' value loadings.

In addition to the dynamic tests, the manufacturing processes have also been approved, both at the forging and machining facilities.

Capus also has continuing on-going tests. Our kingpins are used by a leading European coupling manufacturer, to test their 5th wheel couplings. Some Capus kingpins have exceeded the basic life test by over 20 times.

There is no minimum 'D' value for kingpins specified in the EEC Directive, and therefore this has to be calculated by the trailer builder, knowing all the loadings etc. to the following formula:-


                                                    x 0.6 x Max. Tractor Weight x Max. Trailer Weight 
'D'   9.81                          -------------------------------------------------------------------------------
                                 Max. Tractor Weight + Max. Trailer Weight - Imposed Load Thro' Kingpin

For example:- At 38t gross combination weight:-

                                                                               x 0.6 x 20 x 31 
                        'D'   9.81          -------------------------------------------------------------    = 93.6kN
                                                                               20 + 31 - 12

Or at 44t G.C.W.

                                                                             x 0.6 x 22 x 37
                       'D'   9.81         -------------------------------------------------------------    = 106.5kN
                                                                             12 + 37 - 14

Capus have a range of kingpin assemblies to suit various 'D' values

CAP136 / CAP194 = 108kN

CAP303 = 152kN

CAP262 = 165kN

CAP273 = 180kN

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