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Independent Rubber Suspension (IRS)

AL-KO (IRS) Axles

Featured on over 8 million caravans and trailers around the world, the AL-KO I.R.S. axle system is now the benchmark for fully independent trailer suspension. The trend to independent suspension first revolutionised the passenger car, then four wheel drives and is now the choice for trailers too.

The AL-KO I.R.S. axle has been proven in tough Australian conditions – from dirt tracks to fast freeways, from mountain tracks to desert highways. The demands of marine trailer towing, with the additional affect of salt water, are also met with the AL-KO I.R.S. system.

Conventional suspension componentry can suffer on Australian roads leading to instability and dangerous snaking under heavy loads. AL-KO’s remarkable I.R.S. system makes towing instability thing of the past.

IRS

Here’s how it works

The AL-KO I.R.S. axle uses simple and effective engineering. The hexagonal axle tube houses three rubber elements held in place by a triple fluted inner tube. Suspension movement between bump and rebound compresses the rubber elements thus providing dampening of road shocks.

The unique self-dampening characteristics of the rubber elements slows down the rebound (as shown in figure 1). Every AL-KO I.R.S. axle is manufactured to exact engineering standards and tested for toe-in and camber as well as load rated deflection using state-of-the-art alignment technology. The AL-KO I.R.S. axles are also available in special configurations, such as half axles.

IRS ThumbClick to enlarge

Features and benefits

Some of the features and benefits of the AL-KO I.R.S. are listed below:

  • Suitable for all types of trailer construction
  • Independent suspension
  • Inherent dampening reduces suspension rebound
  • Absorbs shocks, provides better control for more safety
  • Fewer moving parts to wear, i.e. no springs or shackle bolts
  • Withstands 3 and ½ times its rating at shock load
  • Available in single, tandem & tri-axle
  • Each axle tested for toe-in and camber
  • Galvanised / zinc plated
  • Easy fitting
  • Backed by international company
  • Made in Australia for Australian conditions
  • Corrosion resistant for marine applications
  • Digital testing for optimum load rating
  • Can be fitted with different types of brakes
  • Robust “off road” model available

IRS Diagram Thumb

Click to enlarge

Capacity Tube size (T) (MM) Brake options** Stub length / profile (mm) Chassis to stub centre (mm) unloaded * “Nominal” – (H) Max wheel diameter
Highway
100 – 400 62 Unbraked 205 / LM 85 13″
401 – 850 80 10″ Electric 205 / LM 110 14″
851 – 1450 97 10″ Electric 205 or 235 / Slimline 130 14″
851 – 1600 110 10″ Electric 235 / Slimline / Parallel 145 16″
1601 – 2500 120 12″ Electric 255 / 2T 135 16″
“Off Road” (15″/16″ Wheels only)
851 – 1600 110 10″ Electric 235 / Slimline / Parallel 145 16″
1601 – 2500 120 12″ Electric 255 / 2T 135 16″
“Marine” (U-bolt fitted)
100 – 400 62 Mechanical Disc or Unbraked 205 / LM 85 13″
401 – 850 80 Hydraulic or Mech Disc 205 / LM 110 14″
851 – 1450 97 Hydraulic or Mech Disc 205 or 235 / Slimline 130 14″
851 – 1600 110 Hydraulic or Mech Disc 235 / Slimline / 1.5T 145 16″
1601 – 2500 120 Hydraulic or Mech Disc 255 / 2T 135 16″

** All axles are available unbraked or with the brake options as shown.

* “Unloaded” refers to the chassis being supported and suspension arms hanging free.

Figure 1

AL-KO produces a wide range axles for a variety of different needs.

Options available include:

  • Range of capacities (for definition of capacity see figure 1)
  • Zinc plated or galvanised
  • Bolt-on or u-bolt fixing
  • To suit most wheel types
  • To suit common brake types

AL-KO is also able to custom build axles. Please note that the lead time on these options will be longer than our standard 5 working days.

  • Available braked or unbraked
  • Multitude of brake options
  • Special stub axle lengths
  • Special shock absorber mountings on some models
  • Up to 3 ride heights
  • Please contact your nearest AL-KO sales office for a specification sheet to assist you with your axle requirements.