If you believe you need beefy coil spring suspension under your caravan to cope with Australian conditions, you haven’t experienced AL-KO’s Independent Rubber Suspension (IRS). For a start, it’s compact, unobtrusive and fully-sealed. It occupies less space under a caravan or camper, allowing it to sit lower if it’s a blacktop cruiser. This makes it an obvious choice by many leading manufacturers of the lighter, compact caravans that Australians are gravitating towards, because they can require smaller tow cars, are more frugal on fuel and easier to store. Avan, Jurgens, Supreme, Bolwell (on its Air camper) and Karakampa are some of the manufacturers to factor fit it for all of the above reasons.
A COMPLETE SYSTEM
Another appealing feature of AL-KO IRS to these organisations is the system’s manufacturing precision.
The system was developed in Europe and after being fitted under more than 15 million caravans and trailers, it became the benchmark for fully independent trailer suspension. It has been tested rigorously for Australian conditions and is assembled locally at AL-KO’s Dandenong, Vic, plant.
Whereas conventional leaf-spring suspension systems depend on manual fitting and alignment and can distort and deflect under harsh Australian road conditions, AL-KO’s IRS is supplied as a complete, bolt-on system. This means it is perfectly aligned from the outset and maintains that correct alignment under harsh conditions and heavy loads.
What is surprisingly about the IRS axle is its simplicity. A hexagonal, German-made outer axle tube houses three rubber elements that are held in place by a triple-fluted inner tube axle. Road shocks are dampened through compression of these rubber elements via suspension movement between full bump and rebound, allowing the system to withstand three times its rating in shock load. The self-dampening characteristics of these rubber elements slow down the suspension rebound, ensuring a smooth ride over all types of road surfaces. Each individual IRS axle is manufactured to exact engineering standards, with AL-KO using the most advanced technology to test each axle for toe-in and camber, as well as load-rated deflection.
Another important feature of the IRS axle system that makes it attractive to Australian caravan manufacturers is its mounting flexibility. The standard axle can be bolted to a bracket that is fixed to the chassis, while in marine configurations it can be U-bolted onto the chassis rails to allow repositioning along the chassis. This provides optimum towball weight under situations where the load centre is varied.
Caravan manufacturers also like that it is available in half, single, tandem and tri-axle configurations, with a range of capacities and three ride heights. There are different stub axle lengths available, with hubs to suit electric, hydraulic or mechanical brakes, and most wheel types and sizes. This has allowed IRS to be used extensively in a range of applications and enables caravans and trailers of all styles to handle varying terrain and road conditions. Telescopic shock absorbers can be fitted optionally to provide better control, increased safety and reduced suspension rebound.
The central axle can be supplied galvanised for corrosion resistance and, with fewer moving parts, it requires less maintenance. AL-KO Australia even offers a ‘re-rubber’ service, if you decide you want to increase the suspension capacity. Finally, while the AL-KO IRS axle system costs more than leaf springs, it offers most of the benefits combined with lower maintenance costs than other independent trailing arm systems.
What’s not to like?
Want to read more about AL-KO products? Read about how AL-KO has revolutionised caravan towing safety.