Fifth wheel couplings and mounting plates

JOST submitted the patent application for the first cast steel fifth wheel coupling almost 60 years ago. Since then, JOST’s fifth wheel couplings have been a success story around the world. All renowned vehicle manufacturers put their trust in JOST’s expertise and performance.

The extensive product range and high quality are just as crucial for the customer’s trust as the company’s innovative skill and reliable global supply of finished and spare parts.

JOST provides fifth wheel couplings for any application. This includes weight-optimised pressed metal and robust cast steel couplings for imposed loads between 6 and 74 tonnes. Almost all variants are 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 up to 100 kg. Different sensory variants that build on one another guarantee secure operation under all conditions, while the automatic lubrication solutions brought together in the LubeTronic product family save time and money.



Design / features

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.

Excellent quality

  • Patented and reliable design
  • High-quality casting
  • Certification in accordance with ISO/TS 16949
  • Excellent corrosion protection

Wide range of products

  • 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

    Verified safety

    • High level of operating reliability
    • Regular inspections during series production in accordance with ECE R55
    • 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

      High operating comfort

      • 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

        Customer-oriented service

        • Global site and dealer network
        • Expert individual support by sales and customer services
        • Customer support during the planning phase based on CAD data
        • Extensive distribution and global supply of spare parts

          Very easy maintenance

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

              Type plate

              The fifth wheel type plate is attached, placed 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.



              Explanations of the abbreviations

              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
              LT 1P = Low-maintenance version with plastic 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

              oZ = Without drawing
              BH = Mounting height

              Design and components

              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).

              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.


              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.

              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.

              Pivot bearing – Model “K”

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

              Hybrid bearing – Model “H”

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

              Cardan mounting – Model “G”

              The cardanic bearing is designed to allow roll between tractor and semi-trailer under off-road conditions. Due to the high strains it is designed as pivot bearing with wear-resistant bearing bushings. The lateral suspension must be disabled for on-road use.

              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.

              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.


              Plate mounting

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

              Frame mounting

              The fifth wheel coupling is built onto either the frame 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.

              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 can be retrofitted 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. However, 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” version

              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” version

              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” version

              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).

              Did you know …

              … that low-maintenance fifth wheel couplings with plastc top plate liners (version W) can be lubricated, but do not require it? To prevent corrosion of the trailer plate, we recommend light, basic lubrication of the trailer plate within the scope of the maintenance intervals listed in the installation and operating instructions. The locking mechanism must be lubricated. Automatic lubrication systems (such as LubeTronic 1Point) can be installed, as the top plate liners on the lowmaintenance JOST fifth wheel couplings are made not from teflon, but from polyethylene (PE).

              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 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 02/2019
              JSK 26 D 05/2013
              JSK 34 Mounting and operating instructions 05/2019
              JSK 36 / 37 04/2019
              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 04/2017
              JSK 42 K7 06/2013
              LubeTronic 1Point mounting and operating instruction 10/2015
              LubeTronic 5Point mounting and operating instruction 06/2019
              SKS Sensor coupling system 01/2016
              Sensor coupling 05/2018
              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 38/50 Repair Manual 11/2018
              JSK 40 / 42 06/2012
              LubeTronic 5Point Testing Instructions Standard 02/2017
              LubeTronic 5Point Repair Manual 05/2012
              JOST High-performance-lubricant Bio 03/2019
              JSK 37CW / JSK 42W Now standard with LubeTronic 09/2016
              JSK 52 Heavy Duty fifth wheel coupling 07/2013
              LubeTronic 1Point 11/2017
              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 08/2016
              SKS Sensor coupling system 09/2016
              Safety and convenience Sensoric + LubeTronic 09/2016
              Sensor coupling 3-Sensor version 07/2016