Fifth wheel couplings and mounting plates

Fifth wheel couplings are fitted to a tractor unit to connect it to the trailer.


Fifth wheel couplings are vehicle attaching parts that are subject to mandatory design approval and on which the highest safety requirements are placed. We can supply a suitable fifth wheel coupling for all applications, thus always guaranteeing a safe and secure link between the tractor and trailer.


When mounting, using, converting or exchanging our fifth wheel couplings, the vehicle manufacturer’s notes, JOST instructions for mounting and use, and the relevant national regulations must be observed. In Germany these are §§19, 20, 21, 27 of the “StVZO” Motor Vehicle Safety Standards.


The JSK 42 is available with a large selection of pedestals in all common heights and with all common hole patterns for plate and frame assembly. Depending on the model and height, it is possible to reduce the weight by 30 to 60 kg. This fifth-wheel coupling is also exceptionally easy to operate: the convenient handle enables you to release the lock and open the JSK 42 with one hand.

Design / features

JOST fifth wheel couplings fulfil the most stringent requirements in terms of safety, simple operation and ease of servicing. This results in the following benefits:


  • High level of operating reliability
  • Can be used in complicated loading conditions
  • Automatic latch arrangement
  • Only a visual inspection is required to ensure proper engagement
  • Protection against unauthorised opening is possible using a padlock
  • Various sensory solutions available

Ease of servicing

  • Stageless adjustment of the locking mechanism, resulting in lower wear
  • Easily replaceable plastic top plate liners
  • LubeTronic solutions available for easier lubrication
  • All wearing parts available in practical spare parts kits

    Simple operation

    • Long, easy-reach handle
    • The operator does not get dirty
    • The latch is released using a cable
    • Optional: One-handed operation with or without latch

    Product range

    • Couplings for imposed loads of 6-74 tonnes
    • Pressed metal or cast couplings
    • Various bearings and mounting heights
    • Weight-optimised frame assembly possible
    • Low-maintenance variants
    • System solutions such as Sensoric and LubeTronic available for all common fifth wheel couplings

    Range of application

    JOST‘s range includes the perfect fifth wheel coupling with the required imposed load for a wide range of applications – from lightweight distribution traffic to normal road transport; from site traffic to heavy-duty transport.

    Type designation

    The fifth wheel type plate is secured on the side of the coupling plate. When ordering spare parts, please quote the model designation and the serial number.

    Technical Specification

    The ECE directives comprise a catalogue of internationally agreed, consistent technical rules for motor vehicles and add-on parts for motor vehicles. The ECE mark is to be attached to every vehicle or add-on part in motor vehicles for which an ECE approval has been issued. The mark consists of a circle with the capital letter “E” and the ID number of the country issuing the approval. Accordingly, “E1” stands for Germany.

    Fifth wheel couplings and mounting plates are considered add-on parts for tractors used to connect tractors and trailers, making them vehicle connection parts that are subject to type approval.

    For JOST fifth wheel couplings and mounting plates, mainly ECE Directive R55 (Mechanical coupling components of combinations of vehicles) is of relevance. Another important directive for our system solution is ECE Directive R10 (Electromagnetic compatibility).

    The manufacturer’s specifications, the JOST mounting and operating instructions and the applicable national regulations need to be observed when mounting, operating, replacing or retrofitting fifth wheel couplings. In Germany, §§ 19, 20, 21 and 27 of the StVZO (German Road Traffic Licensing Regulation) apply.



    Explenatory notes for the following selection tables

    WA / Maintenance
    M = Manual lubrication
    Z = Prepared for connection to the central lubrication system on the tractor unit
    W = Low-maintenance with plastic top plate liner, lubrication only required on the lock jaw
    M, Z = Available either for manual lubrication or prepared for central lubrication
    LT 1P = Low-maintenance version with top plate liners and LubeTronic 1Point for automatic lock jaw lubrication
    LT 5P = LubeTronic 5Point central lubrication system
    EV = FlashTronic

    ZL / Handle length
    J = Long handle
    K = Short handle

    ST = Standard
    MAN = MAN
    VT = Volvo Truck
    MB = Mercedes-Benz
    RT = Renault Truck
    DAF = DAF
    IV = Iveco
    SC = Scania
    DW = Daewoo
    FO = Ford

    Fitting and component parts

    Winning product advantages impress our customers:
    The construction of JOST fifth wheel couplings guarantees the highest degree of safety.

    The tappets in the insertion area ensure that the king pin is guided accurately into the fifth wheel coupling (2).

    The recess on the patented lock jaw prevents dangerous false locking (3).

    The locking bar, supported on both sides, guarantees an extremely stable safety system (4).

    Plate mounting

    The fifth wheel coupling is fixed to the tractor chassis by means of a mounting plate. Various mounting plate and fifth wheel mounting heights are available to make an accurate match between the height of the fifth wheel and existing trailer systems possible.

    Further advantages

    The adjusting screw allows the lock to be subsequently adjusted continuously, resulting in lower wear.

    Wearing ring easy to replace without dismantling the fifth wheel coupling.

    Hybrid bearing – Model “H”

    The new hybrid bearing combines the advantages of the rubber and the pivot bearing. The rubber cushions are shock-absorbent and maintenance-free. Thanks to the plastic collars it protects the chassis due to its longitudinal elasticity (lateral movement).


    When choosing a fifth wheel coupling, you should especially take into consideration the requirements placed on bearing arrangements, mounting and maintenance. Basically, JOST fifth wheel couplings can be used universally.

    Pivot bearing – Model “K”

    The K-bearing moves especially easy and it is torsion proof and maintenance free. Protects the chassis due to its longitudinal elasticity (lateral movement).

    Rubber bearing – Model “C”

    Fifth wheel couplings with rubber mountings are particularly suitable for poor quality road surfaces. The rubber cushions are shock-absorbent and maintenance-free.

    Always safely coupled: sensor solutions

    A modern vehicle fleet places complex demands on operators and drivers. It is thus essential to make it as safe as possible to operate the vehicle, to keep down the standing time and to avoid accidents. JOST has therefore developed various systems that build on each other to automate or support manual procedures; they thereby not only increase safety, but also efficiency.

    All systems support the driver in the coupling process and / or in checking the fifth wheel coupling locking mechanism. This may be handled via an LED display on the coupling itself, driver assistance systems with remote display and / or remote operation in the driver‘s cab, or KKS, which automates the entire coupling process. Naturally, our sensor solutions can be combined with LubeTronic.

    More information on the sensor solutions in the Systems chapter.

    Pivot bearing – Model “D” and “E”

    The pivot bearing allows low mounting heights and is maintenance-free in the “E” version. It is particularly suitable for use in sliding and dual height fifth wheel systems.

    Chassis mounting

    The fifth wheel coupling is built onto either the chassis or sub-frame of the tractor. The JOST mounting instructions for fifth wheel couplings and mounting plates, as well as the respective mounting instructions supplied by the vehicle manufacturer must be observed when mounting or converting equipment.

    Cardan mounting – Model “G”

    The cardanic bearing is designed to allow roll between tractor and semi-trailer under off-road conditions. The lateral suspension can be disabled for on-road use.

    Optional accessories

    JOST Fleetmaster handle is a handle extension (250 mm longer than the standard handle) with spring clips. JOST Fleetmaster Handle facilitates the opening process particularly where access and space is restricted. It can be secured using the attached spring clips. This enables improved and more secure use of the fifth wheel coupling. JOST Fleetmaster handle is available with with the JSK 36 D fifth wheel coupling and the JSK SL or ProTech sliders.


    Everyone knows that regular, thorough maintenance is the most important factor in ensuring a long life span for a fifth wheel coupling. But lubrication causes downtimes, costs money and harms the environment. To improve the situation, there is a range of solutions that make lubrication easier or even entirely unnecessary for a period of time.

    „W“ Style

    The series JSK 37 CW/EW fifth wheel couplings and all the series JSK 42 fifth wheel couplings in version “W” are equipped with a skid plate on the mounting surface and a wearing ring with plastic insert in the locking mechanism. In conjunction with the maintenance-free rubber or pivot bearing, only one greasing point on the lock jaw needs local lubrication. All wearing parts can be replaced quickly and easily. Low-maintenance fifth wheel couplings therefore save both time and money, as well as conserving resources.

    „LubeTronic 1Point“ variant

    Thanks to the top plate liners, low-maintenance fifth wheel couplings (Series W) have to be lubricated on the lock jaw only, not on the coupling plate. The use of LubeTronic 1Point combined with a specially-coated lock jaw also eliminates this manual procedure. After activation the LubeTronic 1Point suupplies the lock jaw with the optimum amount of grease – guaranteed for 3 years. After this period, LubeTronic and the lock jaw need to be replaced.

    „LubeTronic 5Point“ variant

    LubeTronic 5Point was developed for fifth-wheel couplings without top plate liners. It is a lubrication system that is integrated into the fifth wheel coupling and ensures reliable lubrication of the fifth wheel coupling plate and lock jaw. (Design in accordance with Regulation R55-01, Attachment 7).

    Fifth wheel couplings and mounting plates

    Fifth wheel couplings and mounting plates

    Product overview

    The table below shows the standard versionsdependent on load, bearing and maintenance. Other models are available on request.

    Order No. Lock D value (kN) Imposed load U(t) Rubber bearing Slide bearing Cardan bearing Maintenance
    JSK 26 D 2" 50.0 6 X M
    JSK 34 2" 120.0 16 Z, W
    JSK 36 DA* 2" 152.0 20 X M
    JSK 36 DV 2" 152.0 20 X M
    JSK 37 C 2" 152.0 20 X M
    JSK 37 CW 2" 152.0 20 X W
    JSK 37 CZ 2" 152.0 20 X Z
    JSK 37 E 2" 152.0 20 X Z
    JSK 37 EW 2" 152.0 20 X W
    JSK 37 EA* 2" 152.0 20 X Z
    JSK 37 EAW* 2" 152.0 20 X W
    JSK 37 ER* 2" 152.0 20 X Z
    JSK 37 ERW* 2" 152.0 20 X W
    JSK 37 ME140 2" 126.0 15 X Z
    JSK 37 ME140W 2" 126.0 15 X W
    JSK 42 K0* 2" 152.0 20 X Z, W
    JSK 42 K2-K6* 2" 152.0 20 X Z, W
    JSK 42 K7* 2" 152.0 20 X Z, W
    JSK 42 K8* 2" 152.0 20 X Z, W
    JSK 42 MK 140 2" 126.0 15 X Z, W
    JSK 42 MK 162 2" 152.0 20 X Z, W
    JSK 38 C-1 3 1/2" 260.0 36 X M, Z
    JSK 38 C-1 2" 2" 170.0 28.0
    JSK 38 G-1 3 1/2" 260.0 36 X M, Z
    JSK 38 G-1 2" 2" 170.0 28 X M, Z
    JSK 38 MC 3 1/2" 260.0 36 X M, Z
    JSK 50 3 1/2" 300.0 50 X M


    X = Bearing design

    M = Manual lubrication

    Z = Prepared for connection to the central lubrication system on the tractor unit


    M, Z = Available either for manual lubrication or prepared for central lubrication

    W = Low-maintenance, lubrication only required on the lock jaw

    * = Chassis mountingBefore you use this fifth wheel coupling you must obtain approval from the tractor unit manufacturer



    Mounting and Operating Instructions
    FlashTronic 07/2012
    JSK - first greasing 05/2013
    JSK 26 D 05/2013
    JSK 36 / 37 08/2007
    JSK 36 / 37 07/2013
    JSK 37 - check list 08/2010
    JSK 37 ER 05/2004
    JSK 37 W Top plate liner 08/2003
    JSK 38 / 50 06/2015
    JSK 40 / 42 08/2008
    JSK 40 / 42 02/2013
    JSK 40/42 Connecting / Disconnecting 05/2013
    JSK 42 K7 06/2013
    LubeTronic 1Point mounting and operating instruction 10/2015
    LubeTronic 5Point mounting and operating instruction 07/2012
    SKS Sensor coupling system 01/2016
    Sensor coupling 09/2016
    Repair kits
    JSK 26 D 07/2013
    JSK 36 D 03/2011
    JSK 37 06/2007
    JSK 37 04/2012
    JSK 37 C Cabel guard plate JSK 37 C - Sensor 08/2013
    JSK 37 C Exchanging locking mechanism sensor JSK37C 07/2013
    JSK 38 / 50 06/2012
    JSK 40 / 42 06/2012
    LubeTronic 5Point Testing Instructions 12/2013
    LubeTronic 5Point Repair Manual 05/2012
    JSK 3-2 Technical Information 11/2008
    JSK 36DV Light-weight, Versatile, Proven 09/2014
    JSK 37CW / JSK 42W Now standard with LubeTronic 09/2016
    JSK 37CW LubeTronic 11/2006
    JSK 42 Features 09/2004
    JSK 42MK 04/2008
    JSK 52 Heavy Duty fith wheel coupling 07/2013
    LubeTronic 1Point 09/2016
    LubeTronic 5Point JOST High-Perfomance Lubricant 09/2016
    LubeTronic 5Point The central lubrication system for fifth wheel couplings 09/2016
    LubeTronic 5Point JOST High-Perfomance Lubricant 09/2014
    Original spare parts Better safe than sorry! 09/2014
    Original spare parts Better safe than sorry! 09/2016
    Repairkits Original spare parts 05/2016
    Repairkits Original spare parts 09/2016
    SKS Sensor coupling system 09/2016
    Safety and convenience Sensoric + LubeTronic 09/2016
    Sensor coupling 3-Sensor version 09/2016