Trailer Magazine

A ‘beefed up’ fifth wheel

A ‘beefed up’ fifth wheel

Boasting a considerably stronger design than its predecessor, JOST’s JSK37CX ball-race fifth wheel, fitted to prime movers and Byrne livestock trailers, has found favour with Stockmaster – a livestock haulage company owned by Robert Cavanagh operating from Tamworth and Inverell in northern New South Wales.

Experienced operators are multiskilled in terms of animal husbandry and heavy vehicle operation, with the latter taking place over a broad spectrum of conditions from rough dirt tracks to fast freeways.

This is a fact all too familiar to Robert Cavanagh, a bloke who in the past 20 years has gone from being a single truck owner operator working as a sub-contractor, to running a large fleet of trucks in a livestock haulage operation across NSW, Queensland and the Northern Territory.

Robert got his start in the livestock haulage game in 1985, driving for JT and HM Savage in Tamworth. The company, started by Jim and Helen Savage, later became known as Stockmaster.

He worked there for three years before striking out and buying his own truck – still doing the same work for Jim Savage, but now as a subcontractor with his own vehicle. Little did he realise at that stage that one day he would end up owning Stockmaster.

The Stockmaster trucks have advanced significantly since those early days, with the all-Kenworth fleet fitted with the latest technology equipment including satellite tracking. The operation also uses advanced fatigue management (AFM) to ensure the work is done in the safest and most efficient manner.

Yet it’s the inherent nature of the thoroughfares leading into properties where cattle are loaded that demands much of the various vehicular components, not least the device that keeps the prime mover and trailers connected, commonly called either a fifth wheel or turntable.  

Due to the number of forces acting upon it in different directions, the fifth wheel must be engineered and built to a high degree of strength and precision, with all units sold in Australia undergoing mandatory independent certification to ensure fitnessfor purpose.

Not surprisingly, units fitted to stock hauling combinations need to be at the higher end of the heavy-duty scale and preferably of the ball-race variety rather than fixed units.

As the name suggests, the ball-race fifth wheel is constructed of a top plate connected to the chassis via either a single- (low profile) or double-row ball-bearing slew ring which means the plate stays in the same position relative to the trailer as the vehicle articulates.

In a B-double combination with two ball-race fifth wheels, this allows unimpeded longitudinal oscillation of both trailers relative to each other and the lead trailer relative to the prime mover when turning over uneven terrain.
It also provides superior stability for high centre of gravity loads such as a full load of cattle on a double-deck stock crate.

As a specialist in ball-race fifth wheels, JOST continues to improve its designs to ensure they exceed the demanding expectations of operations like Stockmaster.

This can be seen in its latest offerings – the JSK37CX and CXW which are respective greasy plate and greaseless variants, the latter featuring non-metallic inserts fastened to the plate surface which prevent metal-to-metal contact. 

Stockmaster has been progressively replacing older ball-race units on its prime movers and lead trailers with the JSK37CX due to superior strength under arduous operating conditions. The company’s preferred stock crate builder, Byrne, is also fitting the units to all new Stockmaster lead crates.

With an imposed load rating of 24,000kg and a D-value of 240kN, the JSK37CX incorporates a number of features that enhance its robustness including a new wear ring secured by four bolts rather than the usual three.

It also has sturdier mounting options including weld-on or bolt-on pedestals with six bolts per side fastening the top plate to the pedestals compared to the usual four. In addition, the plate has been reinforced with extra webbing gussets on its underside and a slightly thicker profile.

The JSK37CX turntable is available in heights of 150mm, 170mm, 185mm, 220mm and 250mm. According to JOST, it is ideally suited to a variety of performance-based standards (PBS) applications as well as tanker, livestock and fridge van applications where a higher centre of gravity is inherent. 

“These new units are proving much better at bearing weight than the older turntables (fifth wheels) we were running on our B-double trailers,” says Nick Wiseman, Workshop Manager at Stockmaster.

“The extra two bolts per side holding the top plate to the pedestals and the four-bolt ‘horse shoe’ (wear ring) make a big difference in terms of durability,” he adds. “It simply means they can handle a lot more pressure.”

Nick also says the ball-race design allows more flexibility in movement between the lead and tag trailers in a B-double and a larger, more stable bearing area which helps  reduce the stresses on the assembly over rough terrain.

“We’re gradually replacing all our older fifth wheels with these new JOST ball-race units and all of the new Byrne stock crates we’re buying are fitted with JSK37CX fifth wheels at the factory,” Nick adds. “It’s a no-brainer for us because since we’ve been using the JSK37CX units we’ve had no fifth wheel issues whatsoever.

Fast Fact
JOST’s JSK37CX fifth wheel features six bolts per side instead of the standard four to mount the top plate to the pedestals and four-bolt mounting for the wear ring compared with the usual three.

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