Alko Rubber Suspension Issues Explained

In this brief article we are going to discuss the different  Alko Rubber Suspension problems, what the causes are, and Troubleshooting Tips.

What are the most common Alko Rubber suspension issues? 

The most common Alko Rubber suspension issues are:

  • Rubber Rupture/ breakage
  • Bouncy Operation
  • Dirt Ingress

Alko Rubber Suspension

The Alko Rubber suspension is a specialized unique Rubber suspension setup meant for Two Axle Caravan Suspensions. The Effective ‘Rubber Spring’ element consists of 3 Torsional Rubber Rods parallel to the axle, that twist in resistance to suspension vertical movement.

The arrangement is done to have independent wheel movement at 4 corners of a twin axle caravan suspension set-up.

The axis of the Inner and outer axle tube is Offset from the caravan Wheel Spindle axis in such a way that a vertical movement of the wheel is converted to a twist about the axis of the inner-outer Rubber tube.

The big advantage with this type of suspension is its serviceability. Once the rubber tubes are worn out, the axle inner and outer tubes can be dismantled to replace the internal torsional rubber Rods.

Rubber Rupture / Breakage

  • The internal rubber tends to weather when sitting at rest for long months
  • After periods of idle, the rubber loses its elasticity and tends to rupture faster when resuming operation
  • In most branded axle products, the spares would be available for a replacement

Bouncy Operation

  • The general observation is that the Alko suspension rides bouncy
  • It feels like a primitive leaf spring suspension with no damping
  • The Alko Rubber suspension manufacturer claims that there is no need for external damping as the rubber would do the job
  • The trouble with using rubber for damping is that rubber’s ability to damp lies in a very narrow frequency range of road excitation
  • A conventional vehicle suspension hydraulic shock absorber overcomes the range limitation of rubber by having multiple valve settings that will vary the damping force over a wide range of frequencies.

Dirt Ingress

  • Because the rubber parly protrudes out from between the inner and outer tube, there is always a chance of dirt entering
  • Once mud or dust enters, there is no provision for it to exit
  • Dirt trapped inside will lead to the initiation of rusting of the inner/outer tubes of the axle

How do you know when a torsion axle is bad?

Torsion Axle’s spring element is the rubber chords that are totally concealed, so simple visual inspection of the rubber would not be practical. So you would need another wasuch ways to check for Torsion axle condition:

  • The first method is to check for Axle-Sag. If you had noted down the wheel center distance from the trailer bottom when the axles were new, that piece of information would be very valuable. 

But, in case this initial ride height measurement data is not available, then you could consult the AlKo representative to get a calculated reference value that corresponds to what your trailer’s ride height is supposed to be at. Compare the current measured value against the calculated value and see whether there is any difference. If needed, you could also show this comparison to the technician and ask for an expert opinion. If the measured value falls way below the reference then you need to remove and inspect the axle rubber cords and replace if necessary.

  • The second method to check for Axle rubber deterioration is to check if the axle moves down in reaction to removing weight. The way to do this is to first measure the distance from the axle tube to the trailer bottom reference surface. Now jack up the trailer till there is atleast 2 inches or more of ground clearance and allow the axle to drop down freely. Observe how much the axle is able to drop. For a properly functioning axle, the amount of drop must be at least 1.5 inches.

Conclusion

In this brief article we have discussed the different  Alko Rubber Suspension problems, what the causes are, and Troubleshooting Tips.

Frequently asked Questions

Can an Alko chassis ride heights be lowered?

Unfortunately, Alko does not provide any Ride height adjustment because of the square section of the axle tube. Had it been a spline arrangement, like in a Torsion bar suspension, then probably the rotational adjustment of the axle would have been possible.

How do I order a Torsion Axle?

If you are either building a new trailer or simply replacing the old axle suspension for a Torsion Axle suspension, it is important to select the right size and capacity of axle that is best suited to your trailer. This will ensure that the vibrations in the trailer are reduced.

The factors to consider while ordering a new Torsion axle are:

  • Axle Weight Capacity
  • Axle Bracket Spacing
  • Brakes
  • Ground Clearance Requirement

Do torsion axles need shock absorbers?

The short answer to the question is Yes. But shock absorbers are not essential for torsion axles since there is some amount of damping, as per what torsion axle manufacturers claim.

If you are looking to use your torsion axle trailer in a variety of terrain and road conditions, a shock absorber is definitely recommended. The Shock absorber can cater to the damping requirements to a wide frequency range of road unevenness.

Can you replace the rubber in a torsion axle?

Yes, it is possible to replace the rubber chords in the Alko Rubber Torsion Axle. This is easily done by a technician from the supplier end. It would be best to not use the help of an independent mechanic since he/she would not be accountable for any errors in fitment.

Which is better, a torsion axle or a spring axle?

If you look at the cost and ease of repair, the leaf spring would score over the torsion axle. Leaf Springs are common and it is easy to find mechanics who can service a leaf spring. The Rubber Torsion axles are specialized items that require a technician who has specific product servicing experience. So finding a repair facility in remote areas for the torsion axle could be a challenge. 

Since semi-elliptical leaf springs, the interleaf  friction does give a damping effect apart from a shock absorber that may be part of the axle. This one more area where the leaf spring scores over the torsion axle. The Rubber Torsion axles do tend to be a bit bouncier compared to steel leaf springs.

When it comes to durability, the Torsion axle scores over the steel leaf spring since the rubber chords are a specialized fiber that are designed for durability. The steel springs, on the other hand, undergo a serious amount of wear due to friction.

When comparing maintenance, the Torsion spring is maintenance free and does not require any kind of greasing or lubrication. In the leaf spring, regular lubrication is crucial for getting a proper service life. Also, the leaf spring is an assembly of moving parts that would need regular lubrication and greasing in positions like the eye bearing and inter-leaf areas.

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