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Ifor Williams StockMaster
Ifor Williams StockMaster
Ifor Williams StockMaster
Ifor Williams StockMaster

Introducing Ifor Williams’ largest trailer to date. The StockMaster has a maximum gross weight of 21 tonnes. The commercial axles and running gear make this trailer the most durable and robust trailer from our range.

With dimensions of 24’ by 8’ the StockMaster can be used as either a flat or a livestock trailer.

The trailer has an all over galvanised chassis and a one piece aluminium floor. An admirable feature of the StockMaster is its low ramp angle (20 degrees) and low bed height.

Our StockMaster trailers are built to last and should cost a lot less in the long run compared to trailers built to a lower specification.


  • 24′ x 8′ bed on a galvanised chassis
  • Available as four basic models: Cattle, Decks, Flat with livestock floor, Flat with resin-faced ply floor
  • Design gross trailer weight of 21 tonnes, actual GTW’s depend on current legislation and tyre options chosen.
  • Two Variants: FarmHigh Speed
  • Heavy duty (approved at 13 tonne) commercial S-cam braked axles fitted to all models and variants
  • Ifor Williams load-sharing 4-spring suspension
  • Excellent axle load equalization delivering the best possible braking adhesion – even in off-road operation.
  • Wear protection plates prevent springs rubbing galvanised chassis
  • Ifor Williams 50mm ring eye coupling manufactured from a very tough and wear resistant grade iron – can be unbolted and replaced if required.


High Speed Trailers and Brakes

High speed agricultural trailers are defined as trailers which need to travel at speeds in excess of 20mph. These high speed trailers are required to meet more stringent rules and regulations and are categorised as an O4 Trailer.

Braking for O4 trailers must achieve 45% braking as well as ABS whereas agricultural trailers travelling at less than 20mph are required to achieve 25% and are non ABS.

Two high speed braking systems are available – the first is based on a combination of air and hydraulics, currently used by several other manufacturers. The second is hydraulic ABS, which Ifor Williams will be the first to introduce.

High speed braking using hydraulic ABS gives the farmer the benefit of being able to use tractors with hydraulic braking and no air braking system.


We conducted a thorough reappraisal of every element of 4-spring suspension and came up with what we believe to be the best 4-spring suspension ever produced.

In particular, using our state of the art CAD system we have optimised load sharing over the full range of suspension travel, minimised load transfer under braking and dramatically reduced friction within the suspension which is a major source of poor brake performance.


The axle chosen is tested for loads up to 13 tonnes. This provides an enormous reserve of strength both for wheel bearings and axle beam when using the trailer. The brakes and wheel fixing suit both 19.5″ commercial and 18″ agricultural tyres.

Breakaway Protection

On the trailer is a lanyard which will pull the handbrake on the trailer up before the lanyard snaps, ensuring a safer trailer and peace of mind for the Farmer if something were to go wrong.


Traditionally, the coupling eye is welded directly to the drawbar. This is problematic should the eye ever become damaged or worn. For the StockMaster we have designed a bolt-on coupling which is produced from a high specification material which will dramatically reduce coupling wear and is easy to replace should the eye become damaged.


With 60,000 Livestock trailers in service, the Ifor Williams Livestock design is proved in the field. We have transferred as much as possible of the existing Livestock container design to the StockMaster.


Our StockMaster roof is curved which prevents ice forming and unlike other manufacturers we have kept the roof structures on the outside – we regard this as an essential feature to facilitate cleanliness and hygiene, and in keeping with our current design.


The cross-divisions are extremely strong as is the front bulkhead which will prove essential under high speed braking. Two cross-divisions, as opposed to one, serve the dual function of reducing compartment size and also allowing legal loading right down to very low loading density.

Powered Rear Deck Ramp

A hydraulically operated rear deck ramp for accessing the upper deck is provided. The ramp is powered directly from the tractor hydraulics and removes any manual labour from the loading process. Safety locks are provided to ensure the deck is safe and secure when sheep are being transported. When a decked trailer is required to carry cattle the rear ramp section can be hydraulically lifted and stowed securely in the roof.


We selected the 385/55R19.5 commercial tyre as the optimum combination of diameter and load capacity. (Ensuring we achieve the 20 degree ramp angle required for livestock). Coupled with a maximum 3 tonnes drawbar load these tyres will allow a maximum axle load of 9 tonnes and a gross trailer weight of 21000kg. Commercial tyres have approximately three times the tread depth of a conventional agricultural tyre and the benefit of considerable steel belting to aid puncture resistance.


We have chosen the ISO4107 8-stud 275pcd fixing as it is the most suitable for the 19.5″ and 18″ tyres. This is the most common wheel fitting on European trailers and is stronger than the 10 stud 225pcd alternative.

Flat Trailer

There are 2 floor options, a Livestock Floor (treated softwood planks, covered with a 1 piece aluminium treadplate sheet) or a 24mm thick resin coated ply floor.


Hay Raves / Ladder
Very easy one-man fitting and removal. Ladders weigh approx. 40kg which easily hook and click into the bracket on the front and rear.
Demount System
This kit allows easy container removal using your tractor and forks at home, for flat trailer work and greatly improved utilization.
Non-LED Lights
Interchangeable non-LED lights are available.
Sprung Drawbar Suspension
Using laminated rubber/metal springs which provide springing and damping. Can be converted from fixed to sprung at point of sale. This dampens the noise and absorbs vibrations inevitably created by travelling.
Spare Wheel
Stows in a cradle between the chassis beams at the rear with a winch to pull the wheel in and lift/lower the cradle.

Interested in an Ifor Williams StockMaster Trailer?

Give us a call today on 01832 272218, or email us at - we'll be happy to help!
Copyright © 2021 Barnwell Trailers Limited - Company Reg No. 04843197
Castle Farm, Barnwell, Nr. Oundle, Peterborough, PE8 5QD